- vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 36636] GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
by GCN Circulars 19 Dec '24

19 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38635 SUBJECT: GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits DATE: 24/12/19 14:52:37 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh(a)ynu.edu.cn> Xiangkun Liu, Yu Pan, Dezi Liu, Brajesh Kumar, Xianao Wang, Chenxi Shang, Xufeng Zhu, Xingzhu Zou, Xinlei Chen, Yuanpei Yang, Yehao Cheng, Tao Wang, Guowang Du, Yuan Fang, Jinghua Zhang (all SWIFAR, YNU), Xuhui Han, Pinpin Zhang, Liping Xin, Chao Wu (all NAOC), Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team: The field of GRB 241217A/EP241217B detected by SVOM/ECLAIRs (GCN 38594) and Einstein Probe (GCN 38606) was observed with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Simultaneous uvgriz band photometric observations were conducted starting from 17:09:14 2024/12/17 UT (~12 min after the SVOM/ECLAIRs trigger) and multiple frames with different exposure times were taken. We do not detect any uncatalogued sources in the stacked images within the SVOM/ECLAIRs error region and the 3 sigma upper limits are below. UT start band Exp LimMag (AB) 2024/12/17/T17:09:14 u 300s*3 >21.6 2024/12/17/T17:09:14 g 300s*2, 50s*3 >21.6 2024/12/17/T17:09:14 i 300s*2, 79s*2 >20.6 2024/12/17/T17:13:48 v 300s*3 >21.0 2024/12/17/T17:13:48 r 300s*2, 50s*3 >21.6 2024/12/17/T17:13:48 z 300s*2, 79s*2 >20.3 ------------------------------------------------------------------------------------------------- Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6-m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21. ------------------------------------------------------------------------------------------------- View this GCN Circular online at https://gcn.nasa.gov/circulars/38635. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36635] GRB 241218A: Swift/UVOT Upper Limits
by GCN Circulars 19 Dec '24

19 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38634 SUBJECT: GRB 241218A: Swift/UVOT Upper Limits DATE: 24/12/19 14:17:44 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18(a)psu.edu> M. H. Siegel (PSU) and M. Williams (PSU) report on behalf of the Swift/UVOTteam: The Swift/UVOT began settled observations of the field of GRB 241218A 152 s after the BAT trigger (Williams et al., GCN Circ. 38601). No optical afterglow consistent with the XRT position (D'Elia et al., GCN Circ. 38614) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 152 301 147 >20.7 u_FC 310 559 246 >19.8 white 152 1014 334 >21.0 v 640 1411 97 >18.5 b 565 1337 78 >18.7 u 310 1312 304 >19.8 w1 689 709 19 >21.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.024 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/38634. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36634] EP241217a: optical upper limit with the Liverpool Telescope
by GCN Circulars 19 Dec '24

19 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38633 SUBJECT: EP241217a: optical upper limit with the Liverpool Telescope DATE: 24/12/19 13:13:23 GMT FROM: Amit Kundu at Royal Holloway - UoL/ U of Warwick, UK <amitkundu515(a)gmail.com> A. Kumar, J. R. Maund (RHUL), N. C. Sun (UCAS), W. X. Li, Y. N. Wang (NAOC), and K. Wiersema (Herts) report: We observed the field of Einstein Probe and Swift-XRT detected transient EP241217a (Zhou et al., GCN 38586; Williams et al., GCN 38596) with the IO:O Imager at the 2m Liverpool telescope. We observed 200s x 3 frames in the r-band starting at 2024-12-19 UT 02:14:33.2 (~1.86 days post-trigger). Preliminary photometry on the stacked image was performed and calibrated against the SDSS catalogue stars. We do not detect any source at the location of the optical counterpart candidate of EP241217a (Levan et al., GCN 38587; Izzo & Malesani, GCN 38588; Fan et al. GCN 38592; Mohan et al., GCN 38612; Zhu et al., GCN 38613; Bochenek & Perle, GCN 38615; Brivio et al., GCN 38618) down to a limiting magnitude of > 22. This circular may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38633. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36633] GRB 241209B: EP-FXT afterglow detection
by GCN Circulars 19 Dec '24

19 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38632 SUBJECT: GRB 241209B: EP-FXT afterglow detection DATE: 24/12/19 09:28:48 GMT FROM: Damien Turpin at CEA-Saclay <dturpin-astro(a)hotmail.com> D. Turpin (CEA), Y. L. Wang, T. Zhao, M. J. Liu (NAOC, CAS), Z. Y. Liu, M. Q. Huang (USTC), H. W. Pan, W. Yuan (NAOC, CAS), D. Adrien, C. Plasse (CEA/irfu), J. Guan, C. K. Li, Y . Chen, S. M. Jia, W. W. Cui, D. W. Han, W. Li, C. Z. Liu, F . J. Lu, L. M. Song, J. Wang, J. J. Xu, J. Zhang, S. N. Zhang, H. S. Zhao, X. F . Zhao (IHEP , CAS), Y . Liu, C. C. Jin, C. Zhang, Z. X. Ling, J. Wang, L. P . Xin (NAOC,CAS), E. Kuulkers, A. Santovincenzo (ESA), P . O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA) on behalf of the SVOM and Einstein Probe teams We performed a follow-up observation of GRB 241209B (SVOM/ECLAIRs and GRM, Xie et al., GCN 38478) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The observation started at 2024-12-09T16:01:19 (T-TGRB ~ 12.1hr) for about 3ks of exposure in total and a second epoch was also performed at 2024-12-12T22:35:16 (T-TGRB ~ 3.8 days) for again about 3ks of exposure in total. In the first epoch, an uncatalogued X-ray source is detected by both FXT-A and FXT-B at the position (J2000) RA, DEC = 194.6388, 76.1747 (error=10", 90% C.L.), 5.75 arcminute away from the SVOM/ECLAIRs position (Xie et al., GCN 38478). This position is also consistent with the optical afterglow detected by SVOM/VT (Qiu et al., GCN 38516, GCN 38568) and Swift/XRT source 1 (Williams et al., GCN 38525). This source is no longer detected in the second epoch 3.8 days post GRB trigger time confirming it has significantly faded and is indeed the x-ray afterglow of GRB 241209B. The above observation was made with the EP-FXT instrument. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/38632. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36632] Konus-Wind detection of GRB 241204A (short/hard)
by GCN Circulars 19 Dec '24

19 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38631 SUBJECT: Konus-Wind detection of GRB 241204A (short/hard) DATE: 24/12/19 08:22:13 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> V. Panteleeva, D. Frederiks, A. Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The short-duration GRB 241204A (Fermi-LAT detection: Bissaldi et al., GCN 38436; Fermi-GBM detection: Godwin et al., GCN 38441) triggered Konus-Wind at T0=13159.909 s UT (03:39:19.909). The burst light curve shows a single pulse which starts at ~T0 and has a total duration of ~0.1 s. The emission is seen up to ~7 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB241204_T13159/ As observed by Konus-Wind, the burst had a fluence of 6.20(-1.01,+1.11)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.004 s, of 1.45(-0.34,+0.37)x10^-4 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.064 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.22(-0.11,+0.12) and Ep = 3550(-1308,+4267) keV (pgstat = 62/73 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -1.62 (pgstat = 62/72 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/38631. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36631] GRB 241218A: NOT optical upper limits
by GCN Circulars 19 Dec '24

19 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38630 SUBJECT: GRB 241218A: NOT optical upper limits DATE: 24/12/19 02:10:25 GMT FROM: syfu(a)nao.cas.cn S.Y. Fu (NAOC), D. B. Malesani (DAWN/NBI and Radboud Univ.), Z.P. Zhu, X. Liu, D. Xu (NAOC), L. Cotter (UCD), A. Amanda Djupvik (NOT) report on behalf of a large collaboration: We observed the field of GRB 241218A detected by Swift (Williams et al., GCN 38601) using the StanCam instrument mounted on the Nordic Optical Telescope (NOT), 3 x 300 s in the Bessel R band and 5x200 s in the Sloan z band frames were obtained. Observations started at 04:37:19 UT on 2024-12-18, i.e., 4.5 hr after the trigger. No new source is detected in the stacked frames within the enhanced Swift/XRT error circle (Beardmore et al. GCN 38604), with the limiting magnitudes of R > ~ 21.7 (Vega, converted from r-band, Lupton 2005) and z > ~ 21.0 (AB), calibrated with nearby Pan-STARRS stars and without Galactic extinction correction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38630. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36630] GRB 241218A: Swift-BAT refined analysis
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38629 SUBJECT: GRB 241218A: Swift-BAT refined analysis DATE: 24/12/18 22:02:20 GMT FROM: Mike Moss at NASA GSFC <mikejmoss3(a)gmail.com> R. Gupta (GSFC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU), M. A. Williams (PSU) (i.e. the Swift-BAT team): Using the data set from T-520 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 241218A (trigger #1275005) (M. A. Williams, et al., GCN Circ. 38601). The BAT ground-calculated position is RA, Dec = 185.687, 29.984 deg which is RA(J2000) = 12h 22m 44.8s Dec(J2000) = +29d 59' 04.2" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 52%. The mask-weighted light curve shows a single pulse of emission lasting 40 seconds with a possible second pulse at T+70 seconds. The T90 (15-350 keV) is 23.31 +- 4.19 sec (estimated error including systematics). The time-averaged spectrum from T-1.82 to T+26.16 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.31 +- 0.26. The fluence in the 15-150 keV band is 5.5 +- 1.0 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+16.64 sec in the 15-150 keV band is 0.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1275005 View this GCN Circular online at https://gcn.nasa.gov/circulars/38629. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36629] GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38628 SUBJECT: GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits DATE: 24/12/18 21:51:30 GMT FROM: Thomas Hussenot-Desenonges at IJCLab <thomas.hussenot(a)ijclab.in2p3.fr> T. Hussenot-Desenonges (IJCLAB), F.Colas (Obs-Paris), L. De Almeida, W. Corradi, N. Sasaki, F. Navarete (LNA), H. Peng (THU), H. Lau Jun Xian (Tsinghua Univ.), S. Antier (OCA), C. Andrade (UMN), S. Karpov (FZU), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), N. Guessoum (AUS), A. Klotz (IRAP), D. Turpin (CEA-Saclay/Irfu) on behalf of the GRANDMA collaboration: We observed the field of GRB 241217A / EP241217B, detected by SVOM/ECLAIRs (GCN 38594) and Einstein Probe (GCN 38606), using T1MPicduMidi, starting 5 hours after T0. We obtain the following optical 5-sigma upperlimit at the SVOM/VT position (GCN 38600): | Tstart (UTC) | Telescope | Exposure | Filter | Magnitude | | 2024-12-17T22:09:50 | T1MPicduMidi | 126x60s | r | >21.46 (AB) | We also do not detect any uncatalogued sources within the SVOM/ECLAIRs error region, down to a 5-sigma upper limit of r > 21.35 (AB). All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022), and calibrated with the Pan-STARRS DR1 catalogue. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). View this GCN Circular online at https://gcn.nasa.gov/circulars/38628. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36628] EP 241217a: NIR detection with P200/WIRC
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38627 SUBJECT: EP 241217a: NIR detection with P200/WIRC DATE: 24/12/18 21:10:18 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197(a)gmail.com> Viraj Karambelkar (Caltech), Tomas Ahumada (Caltech), and Mansi Kasliwal (Caltech) report: We observed the location of EP 241217a (Zhou et al., GCN 38586;) in the NIR J-band and Ks-band with the Wide-Field Infrared Camera (WIRC, Wilson et al. 2003) on the 200-inch Hale telescope at Palomar Observatory. Observations began on 2024-12-18 01:40:00 UT (approx. 20 hours after the EP detection), and comprise a series of 36 x 45 s exposures in the J-band and 17 x 30 s in the K-band. We detect a possible source at the Gemini counterpart location (Levan et al., GCN 38587; Fan et al. GCN 38592; Levan et al. GCN 38593). We measure a brightness of J ~ 20.7 +/- 0.1 mag (AB) and K ~ 19.3 +/- 0.1 mag (AB). We thank Héctor Arce and the P200 staff for granting the observations. We subsequently observed this transient with NIRES (Wilson et al. 2004) on the Keck II telescope starting 2024-12-18 05:00:00 UT. We thank Michael Lui, and the Keck staff for facilitating the observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/38627. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36627] EP 241217a: Possible J-band detection with WINTER
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38626 SUBJECT: EP 241217a: Possible J-band detection with WINTER DATE: 24/12/18 20:08:50 GMT FROM: Tomas Ahumada Mena at Caltech <tahumada(a)caltech.edu> Tomás Ahumada (Caltech), Viraj Karambelkar (Caltech), Geoffrey Mo (MIT), Benjamin Schneider (LAM), Danielle Frostig (CfA), Robert Stein (UMD), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report: We automatically observed the field of EP 241217a (Zhou et al., GCN 38586;) in the near-infrared J-band with the Palomar 1-m telescope, equipped with the 1-square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024). Observations were triggered automatically and began at 2024-11-17T11:51:46 UTC (~6.25 hours after the EP event), consisting of 30 x 120 s exposures. The images were processed using the WINTER data reduction pipeline (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565) using images from the UKIRT Hemisphere survey (Dye et al. 2018) as references for image subtraction. We detect a possible source at the Gemini counterpart location (Levan et al., GCN 38587; Fan et al. GCN 38592; Levan et al. GCN 38593). This source is near the threshold of our stacked image, and we measure a brightness of J ~ 18 +/- 0.4 mag (AB). No source is present at this location in the reference UKIRT images to a depth of ~21 mag (AB). We caution that our detection is close to the image's limiting magnitude, and we strongly encourage further observations to confirm the source as real and to assess its NIR brightness. WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/38626. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36626] GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38625 SUBJECT: GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection DATE: 24/12/18 18:49:05 GMT FROM: rhamburg(a)usra.edu M. E. Ravasio (Radboud Univ.), P. Veres (UAH), R. Hamburg (USRA), E. Burns (LSU) and P.G. Jonker (Radboud Univ.) report on behalf of the Fermi-GBM Team: Fermi-GBM had full spatial and temporal coverage of the transient GRB 241217A/EP241217B detected by SVOM and EP (GCN 38594; GCN 38606). There was no Fermi-GBM onboard trigger around the SVOM trigger time T0=2024-12-17T16:57:13 UTC or the EP trigger time at T0+53 s (16:58:04 UTC). Fermi-GBM had exited SAA approximately 7 mins before T0, and given the rapidly decreasing background, on-board triggering was difficult during this time. The GBM Targeted Search [1], the most sensitive, coherent search for GRB-like signals in GBM identified a transient most significantly at T0+156 s (16:59:48 UTC) on a 32 s timescale with a false alarm rate of 6.5e-05 Hz. The localization is consistent with the SVOM and EP locations. The transient was best-fit with a "soft" spectrum (i.e., a Band function with Epeak = 70 keV, alpha = -1.9, beta = -3.7) for a GRB. The full GBM light curve consists of multiple peaks and the time-averaged spectrum from T0-44 s (16:56:29 UTC) to T0+190 s (17:00:23 UTC) is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.68 +/- 0.21 and the cutoff energy, parameterized as Epeak, is 36 +/- 2 keV. The event fluence (10-1000 keV) in this time interval is (1.24 +/- 0.05)E-05 erg/cm^2. The spectral analysis results presented above are preliminary. [1] Goldstein et al. 2019 arXiv:1903.12597 View this GCN Circular online at https://gcn.nasa.gov/circulars/38625. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36625] EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38624 SUBJECT: EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations DATE: 24/12/18 16:30:33 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> H. Zhou (PMO, CAS), S.-F. Zhu (USTC), M. H. Zhang (NAO, CAS), H. Sun (NAO, CAS), C. C. Jin (NAO, CAS) report on behalf of the Einstein Probe team: Since 2024-12-17T05:34:10 (UTC, about 113 seconds before the trigger time), EP241217a (Zhou et al., GCN 38586) was detectable for with the Wide-field X-ray Telescope (WXT) at low significance and peaked at about 52 seconds before the trigger. The mean and peak WXT count rate of the EP241217a before the slewing of EP is about 0.3 cnt/s and 1 cnt/s, respectively. The average 0.5-4 keV spectrum can be fitted with an absorbed power law with a photon index of 1.93 (-0.59, +0.71) (with a fixed Milky Way equivalent hydrogen column density of 1.88 x 10^21 cm^-2). The derived average unabsorbed 0.5-4 keV flux is (7.3+/-2.7) x 10^-10 erg/s/cm^2. In addition to the autonomous follow-up observation, we performed two follow-up observations of EP241217a with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The first observation began at 2024-12-17T13:21:55 (UTC, 7.64 h after the trigger of EP241217a), and the exposure time is about 3ks. The second observation began at 2024-12-18T09:57:58 (UTC, 28.37 h after the trigger), but the telemetry data has not been received yet. Preliminary results of the autonomous (Zhou et al., GCN 38586) and the first follow-up observations are summarized: +--------------------------------------------------------------------------------+ T_Start [UTC] | T_mid - T0 [h] | Exp [s] | Flux (0.5-10 keV) [erg/s/cm^2] +--------------------------------------------------------------------------------+ 2024-12-17T05:38:53 | 1.02 | 3132 | (6.23+/-0.46) x 10^-12 * 2024-12-17T13:21:55 | 8.18 | 2966 | (1.35+/-0.22) x 10^-12 +--------------------------------------------------------------------------------+ All fluxes are observed values derived with FXT-A data. * The autonomous follow-up observation lasts for about 6ks with effective exposure time of 3.1ks. The X-ray flux decays quickly in the autonommous follow-up observation, for the first 911s exposure segment, the mid time is about 10.4 min after the trigger and the 0.5-10keV flux is about 2 x 10^-11 erg/s/cm^2. The derived temporal decay index is about 0.73+/-0.35, and the estimated flux at the Swift-XRT epoch is (1.52+/-0.27) x 10^-12 erg/s/cm^2, which is consistent with the value reported by Swift-XRT (Williams et al., GCN 38596). Considering the shallow decay observed in the optical band (Izzo et al., GCN 38588; Levan et al., GCN 38587; Fan et al., GCN 38592; Jin et al., GCN 38607; Mohan et al., GCN 38612; Zhu et al., GCN 38613; Bochenek et al., GCN 38615), more follow-up observations are encouraged to monitor the X-ray transient EP241217a with a moderate redshift of 4.59 (Levan et al., GCN 38593). The time-averaged FXT spectra of the autonomous and the first follow-up observations are fitted by the absorbed powerlaw model with the fixed Milky Way equivalent hydrogen column density nH of 1.88 x 10^21 cm^-2. The best-fitted model shows that the intrinsic absorption is negligible, and the photon index is 1.76+/-0.11 (1.96+/-0.17) for the autonomous (the first) follow-up observation. Our fitting results are consistent with the Swift-XRT results (Williams et al., GCN 38596). Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/38624. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36624] GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38623 SUBJECT: GRB 241217A / EP241217b: Nanshan/HMT optical upper limit DATE: 24/12/18 15:03:31 GMT FROM: Zipei Zhu at NAOC <zpzhu(a)nao.cas.cn> Z.P. Zhu, X. Liu, S.Y. Fu, J. An, S.Q. Jiang, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report on behalf of a large collaboration: We observed the field of GRB 241217A/EP241217b detected by SVOM (Marius et al., GCN 38594) and Einstein Probe (Zhou et al., GCN 37492), using the HMT-0.5m telescope located at Nanshan, Xinjiang, China. Observations started at 17:18:54 UT on 2024-12-17, i.e. 21.7 mins after the trigger. The reported optical afterglow (Qiu et al., GCN 38600) is not detected in our stacked image, down to a 5-sigma limiting magnitude of ~ 18.5 mag (AB) at 0.84 hr post-burst, calibrated against G-band of Gaia DR3 and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38623. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36623] GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38622 SUBJECT: GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission. DATE: 24/12/18 14:58:26 GMT FROM: Diego Gotz at CEA <diego.gotz(a)cea.fr> D. Götz, H. Goto, P. Ferrando, A. Meuris, M. Moita, C. Plasse, A. Sauvageon (CEA), P. Maggi, L. Michel (ObAS), C. van Hove, F. Robinet, N. Leroy (IJCLab), A. Fort, J. Joubert, K. Mercier, S. Crepaldi (CNES) on behalf of the MXT Commissioning Team, SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Olivier Godet (IRAP), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shaolin Xiong (IHEP), Bing Zhang (UNLV), M. Brunet (IRAP) report on behalf of the SVOM team: GRB 241217A (Brunet et al. GCN 38594, Zhou et al. GCN 38606) was observed by SVOM/MXT after an automatic SVOM slew starting at 17:01:09 UT for 12.8 ks (3.5 hr) after the slew. Its position measured with the full MXT dataset is consistent with the one reported by SVOM/VT (Qiu et al. GCN 38600) and Swift/XRT (Williams et al. GCN 38599). After an initial decrease lasting about 300 s, possibly related to the end of the prompt emission, the X-ray light curve enters a bright long lasting emission phase (average 0.5-10 keV flux 8.5e-10 erg/cm2/s) with a superimposed flaring activity up to the end of the observation. If the initial decay is indeed related to the prompt emission, the duration of the GRB would be about 550 s (assuming the trigger time of 16:57:13 UTC, GCN 38594). If we consider the X-ray long lasting emission being part of the prompt emission, GRB 241217A would qualify as an ultra-long GRB, as also suggested by the EP/WXT light curve (Zhou et al. GCN 38606), or potentially as a jetted TDE. Further X-ray observations are planned. The average spectrum of the X-ray emission can be well fit by an absorbed single power law model with a power law photon index of 1.38+/-0.05 and an NH value of 0.12+/-0.01 x 1e22 /cm2. Follow-up observations at other wavelengths are encouraged. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. MXT was developed jointly by CEA, CNES, University of Leicester, IJCLab and MPE. The SVOM point of contact for this burst is: Brunet Marius (marius.brunet(a)irap.omp.eu) View this GCN Circular online at https://gcn.nasa.gov/circulars/38622. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36622] GRB 241217A / EP241217b: NOT optical upper limits
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38621 SUBJECT: GRB 241217A / EP241217b: NOT optical upper limits DATE: 24/12/18 14:57:47 GMT FROM: Zipei Zhu at NAOC <zpzhu(a)nao.cas.cn> Z.P. Zhu, X. Liu, D. Xu (NAOC), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. Amanda Djupvik (NOT), Laura Cotter, Antonio Martin-Carrillo (UCD), Jesse Palmerio (CEA/Irfu) and Susanna D. Vergani (GEPI / Obs. de Paris) report on behalf of a large collaboration: We observed the field of GRB 241217A / EP241217b detected by SVOM (Marius et al., GCN 38594) and Einstein Probe (Zhou et al., GCN 37492), using the StanCam and NOTCam instruments mounted on the Nordic Optical Telescope (NOT), with 9x200s in the SDSS-z band and 18x60 s photometry in the J band. Observations started at 23:09:34 UT on 2024-12-17, i.e. 6.2 hr after the trigger. The optical afterglow (Qiu et al., GCN 38600) is not detected in any of the stacked images, down to the following 5-sigma upper limits: T_mid (UT) | T_mid (hr) | filter | Exposue|5-sigma U.L. (AB) 2024-12-17T23:20:59 | 6.396 | J | 18x60s | 19.5 2024-12-18T01:05:01 | 8.130 | z | 9x200s | 21.3 calibrated with nearby Pan-STARRS and 2MASS stars, and not accounting for any Galactic extinction correction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38621. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36621] GRB 241218A: REM optical upper limit
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38620 SUBJECT: GRB 241218A: REM optical upper limit DATE: 24/12/18 13:54:03 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R. Brivio, M. Ferro, P. D’Avanzo (INAF-OAB), D. B. Malesani (DAWN/NBI and Radboud Univ.) S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 241218A detected by Swift (Williams et al., GCN 38601) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z bands, starting on 2024 December 18 at 08:05:53 UT (i.e. 8.0 hours after the Swift trigger), and lasting for about 1 hour. From preliminary photometry we do not detect any optical counterpart at the XRT enhanced position (Beardmore et al., GCN 38604) down to the following 3sigma magnitude upper limits: r > 19.2 (AB; calibrated against the Pan-STARRS catalogue) at a mid-time of t - t0 = 8.4 hr after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/38620. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36620] GRB 241217A/EP241217b: REM optical/NIR upper limits
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38619 SUBJECT: GRB 241217A/EP241217b: REM optical/NIR upper limits DATE: 24/12/18 13:52:17 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> M. Ferro, R. Brivio, P. D’Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 241217A detected by SVOM (Brunet et al., GCN 38594), also detected by Swift-XRT (Williams et al., GCN 38599) and EP-WXT (Zhou et al., GCN 38606) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2024 December 18 at 03:02:28 UT (i.e. 10.1 hours after the SVOM trigger), and lasting for about 1.5 hour. From preliminary photometry we do not detect any optical or NIR counterpart at the XRT position down to the following 3sigma magnitude upper limits: r > 20.9 (AB; calibrated against the Pan-STARRS catalogue) at a mid-time of t - t0 = 10.9 hr after the trigger, H > 16.6 (Vega; calibrated against the 2MASS catalogue) at a mid-time of t - t0 = 10.8 hr after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/38619. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36619] EP241217a: REM optical/NIR upper limits
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38618 SUBJECT: EP241217a: REM optical/NIR upper limits DATE: 24/12/18 13:50:59 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R. Brivio, M. Ferro, P. D’Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of EP241217a (Zhou et al., GCN 38586), also detected by Swift-XRT (Williams et al., GCN 38596) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2024 December 18 at 00:45:27 UT (i.e. 19.1 hours after the EP-WXT trigger), and lasting for about 1 hour. From preliminary photometry we do not detect any counterpart in the optical and NIR images at the position of the optical afterglow (Levan et al., GCN 38587; Izzo & Malesani, GCN 38588; Fan et al. GCN 38592; Mohan et al., GCN 38612; Zhu et al., GCN 38613; Bochenek & Perle, GCN 38615) down to the following 3sigma magnitude upper limits: r > 20.8 (AB; calibrated against the Pan-STARRS catalogue) at a mid-time of t - t0 = 19.6 hr after the trigger, H > 16.6 (Vega; calibrated against the 2MASS catalogue) at a mid-time of t - t0 = 19.5 hr after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/38618. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36618] GRB 241218a: Liverpool Telescope optical follow-up
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38617 SUBJECT: GRB 241218a: Liverpool Telescope optical follow-up DATE: 24/12/18 13:28:21 GMT FROM: A. Bochenek at Liverpool John Moores University <a.m.bochenek(a)2023.ljmu.ac.uk> A. Bochenek and D. A. Perley (LJMU) report: We observed the Gamma-Ray Burst GRB 241218a (Williams et al., GCN 38601) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 3x200s exposures with the SDSS r’ and SDSS i’ filters starting at 2024-12-18 03:33:56 UT, approximately 3.4 hours after the trigger. We do not detect any new sources at the Swift/XRT enhanced position (Beardmore et al., GCN 38604). The 3-sigma limiting magnitudes on the stacked images are r > 20.9 mag and i > 21.0 mag, calculated using the nearby PanSTARRS secondary standards as reference. The photometry was not corrected for extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38617. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36617] GRB 241217a: Liverpool Telescope optical follow-up
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38616 SUBJECT: GRB 241217a: Liverpool Telescope optical follow-up DATE: 24/12/18 13:21:40 GMT FROM: A. Bochenek at Liverpool John Moores University <a.m.bochenek(a)2023.ljmu.ac.uk> A. Bochenek and D. A. Perley (LJMU) report: We observed the field of GRB 241217a (Marius et al., GCN 38594) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 4x200s exposures with the SDSS r’ and SDSS i’ filters starting at 2024-18-09 01:09:11 UT, approximately 8.2 hours after the trigger. We do not detect any new sources at the Swift/XRT afterglow position (Williams et al. GCN 38599) nor within the SVOM/VT error circle (Qiu et al. GCN 38600). The 3-sigma limiting magnitudes on the stacked images are r > 21.7 mag and i > 22.0 mag. The photometry was obtained using nearby PanSTARRS secondary standards and was not corrected for extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38616. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36616] EP241217a: Liverpool Telescope optical follow-up
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38615 SUBJECT: EP241217a: Liverpool Telescope optical follow-up DATE: 24/12/18 12:28:22 GMT FROM: A. Bochenek at Liverpool John Moores University <a.m.bochenek(a)2023.ljmu.ac.uk> A. Bochenek and D. A. Perley (LJMU) report: We observed the field of the fast X-ray transient EP241217a (Zhou et al., GCN 38586) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 6x100s exposures in the SDSS i’ filter starting at 2024-12-17 21:03:57 UT, approximately 15.5 hours after the trigger. We report a detection of the optical counterpart in the stacked images of i = 20.26 ± 0.09 mag, at a position consistent with Levan et al., GCN 38587, Williams et al., GCN 38596. This is in line with i-band decay observations from Mohan et al., GCN 38612. The inferred red r-i colour (by comparison with values reported by Izzo et al., GCN 38588, Fan et al., GCN 38592, Jin et al., GCN 38607, Zhu et al., GCN 38613) is consistent with the high spectroscopic redshift of z~4.6 reported by Levan et al., GCN 38593. The photometry was obtained using nearby PanSTARRS standards and was not corrected for extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38615. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36615] GRB 241218A: Swift-XRT refined Analysis
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38614 SUBJECT: GRB 241218A: Swift-XRT refined Analysis DATE: 24/12/18 11:32:21 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), C. Salvaggio (INAF-OAB), M. A. Williams (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 6.1 ks of XRT data for GRB 241218A, from 131 s to 23.9 ks after the BAT trigger. The data comprise 19 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=2.7 (+0.4, -0.3). At T+539 s the decay flattens to an alpha of -1.5 (+0.0, -0.7) before breaking again at T+972 s to a final decay with index alpha=1.52 (+0.19, -0.15). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.72 (+0.22, -0.12). The best-fitting absorption column is consistent with the Galactic value of 2.2 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.8 x 10^-11 (3.9 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.2 (+/-4.5) x 10^20 cm^-2 Galactic foreground: 2.2 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.72 (+0.22, -0.12) If the light curve continues to decay with a power-law decay index of 1.52, the count rate at T+24 hours will be 4.1 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.5 x 10^-14 (1.6 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01275005. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38614. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36614] EP241217a: NOT optical observations
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38613 SUBJECT: EP241217a: NOT optical observations DATE: 24/12/18 10:46:03 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> Z.P. Zhu, X. Liu, D. Xu (NAOC), J.P.U. Fynbo (DAWN/NBI), A. Amanda Djupvik (NOT) report on behalf of a large collaboration: We observed the field of EP241217a detected by Einstein Probe (EP, Zhou et al., GCN 38586), using the StanCam instrument mounted on the Nordic Optical Telescope (NOT), with 9 x 180 s in the R band. Observations started at 19:14:21 UT on 2024-12-17, i.e. 13.6 hr after the trigger. The previously reported optical counterpart (Levan et al., GCN 38587 & 38593; Izzo et al., GCN 38588; Fan et al., 38592; Jin et al., GCN 38607) is clearly detected in our stacked image, with a preliminary magnitude of R ~ 20.5 mag (AB), calibrated with nearby PanSTARRS stars and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38613. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36613] EP241217a: GROWTH-India Telescope optical observations
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38612 SUBJECT: EP241217a: GROWTH-India Telescope optical observations DATE: 24/12/18 10:29:05 GMT FROM: V. Swain at IIT Bombay <vishwajeet.s(a)iitb.ac.in> T. Mohan, V. Swain, R. Kumar, A.P. Saikia, D. Eappachen, A. Balasubramanian, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team: We observed the field of EP241217a reported by EP-WXT (Zhou et al., GCN 38586) with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2024-12-17T15:31:11 UT, i.e., 9.9 hours after trigger time. We obtained multiple exposures of 360 seconds in the r', i' and z' filters. We detected the source in i'-band at the coordinates given by Gemini North (Levan et al., GCN 38587). The obtained photometry are as follow: | MJD (mid)| tmid-t0 (in hours) | Filter | Total Exposure (s) | Magnitude (AB) | Lim Mag (5-sigma) | -------------|----- | ------ | ------------------ | -------------- | ---- | | 60661.77892 |13.09| r' | 5x360 | - | 20.8 | | 60661.69600 | 11.10| i' | 3x360 | 19.53 +/- 0.10 | 20.4 | | 60661.75717 |12.57 | i' | 5x360 | 19.92 +/- 0.11 | 20.4 | | 60661.73551 |12.05 | z' | 5x360 | - | 19.2 | The measurement is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. The i band flux at the epoch of our observation is higher than the reported r and z band fluxes at earlier epochs in other optical detections (Levan et al., GCN 38587, Izzo et al., GCN 38588, Fan et al., GCN 38592, Jin et al., GCN 38607). We note that there is a WISE source present [WISEA J030746.09+305548.3](https://vizier.cds.unistra.fr/viz-bin/VizieR-S?WISEA%20J030746.09%2b305548.3s://) at the location, with a W1 band magnitude 17.591 +- 0.2. Further observations are necessary to determine the nature of the source and presence of any variability. The GROWTH India Telescope (GIT; Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/. View this GCN Circular online at https://gcn.nasa.gov/circulars/38612. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36612] GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38611 SUBJECT: GRB 241218A: NUTTelA-TAO / BSTI Optical Limits DATE: 24/12/18 10:05:41 GMT FROM: Zhanat Maksut at Nazarbayev University <zhanat.maksut(a)nu.edu.kz> Z. Maksut (NU), B. Grossan (UCB, NU), T. Komesh (NU), Z. Abdullayev (NU), M. Krugov (FAI) and E. Abdikamalov (NU) report on behalf of the Energetic Cosmos Laboratory: The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) observed the field of GRB 241218A, 12 seconds after receipt of an automated GCN / BAT position alert, in Sloan g' and r' bands, with the Burst Simultaneous Three-Channel Imager (Grossan, Kumar & Smoot 2019, JHEA, 32, 14). We started observations of GRB 241218A (Williams et al., GCN 38601; Strausbaugh et al., GCN 38605) at UT 00:13:43 on 2024-12-18, 292 seconds after the BAT trigger. Observations were made in clear conditions. We report the following upper limit results: start time t_m-t0(s) end time UL g' UL r' exposure_time (image x s) ----------------------------------------------------------------------- 00:26:30 1191 00:29:30 19.51 19.57 3 x 60 The start and end time is in UT. t_m is the middle time, t0 is the BAT trigger time, t_m-t0 is given in seconds. UL gives the 5 sigma upper limit sensitivity in magnitudes, for images co-added to the given exposure time. Calibration was done with 4 Pan-STARRS catalog stars on our images. No color corrections were applied to the values above. ---------------------------------- NU = Nazarbayev University, Astana, Kazakhstan UCB = University of California, Berkeley, USA FAI = Fesenkov Astrophysical Institute, Kazakhstan View this GCN Circular online at https://gcn.nasa.gov/circulars/38611. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36611] EP241119a: 7DT Optical upper limits
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38610 SUBJECT: EP241119a: 7DT Optical upper limits DATE: 24/12/18 08:33:49 GMT FROM: Gregory Paek at Seoul National University <gregorypaek94(a)gmail.com> Gregory S.H. Paek (SNU ARC/SNU), Myungshin Im (SNU ARC/SNU), Hyeonho Choi (SNU ARC/SNU), Seo-Won Chang (SNU ARC/SNU), and Ji Hoon Kim (SNU ARC/SNU) report on behalf of the 7-Dimensional Telescope collaboration We searched for the optical counterpart of the bright X-ray flare, EP241119a (Zhang et al., GCN #38281) using the 7-Dimensional Telescopes (7DT). Approximately 13.6 hours following the initial detection (2024-11-19T17:53:20 UTC), we targeted the localization center provided by the Wide-field X-ray Telescope (WXT) and confirmed by the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission at RA, Dec = 84.1062 deg, 3.8404 deg with an uncertainty of 10 arcsecs. Observations were made with thirteen 7DT units in twenty medium-band filters, denoted as m400, m425, then through m875, in which the numeric values indicate their central wavelengths in nanometers. Each medium-band filter has a bandwidth of 25nm. Observations for two broad-band filters were also carried out. In the preliminary result, no significant transient event was identified. Photometric flux calibration was performed using synthetic photometries derived from the Gaia DR3 XP catalog (Gaia Collaboration et al. 2022) within the AB magnitude system. The 5-sigma upper limits (AB) range from 16.8 to 19.3 mag in the medium-band filters, reaching 20.1 mag in the g-band and 19.9 mag in the r-band. Observations were conducted under suboptimal conditions, potentially limiting our search sensitivity. ------ Filter Date-obs[UT] Exp.time[s] Depth(5sigma) m400 2024-11-20T07:34:48 300 18.767 m425 2024-11-20T07:34:47 300 18.977 m450 2024-11-20T07:29:19 300 19.008 m475 2024-11-20T07:34:49 300 18.947 m500 2024-11-20T07:29:17 300 19.280 m525 2024-11-20T07:34:46 300 19.228 m550 2024-11-20T07:29:19 300 18.866 m575 2024-11-20T07:34:49 300 18.892 m600 2024-11-20T07:29:23 300 19.166 m625 2024-11-20T07:35:00 300 18.964 m650 2024-11-20T07:29:20 300 18.466 m675 2024-11-20T07:34:48 300 18.537 m700 2024-11-20T07:29:18 300 18.382 m725 2024-11-20T07:34:47 300 18.159 m750 2024-11-20T07:29:18 300 18.215 m775 2024-11-20T07:34:48 300 17.981 m800 2024-11-20T07:29:19 300 17.748 m825 2024-11-20T07:34:47 300 17.491 m850 2024-11-20T07:29:18 300 17.214 m875 2024-11-20T07:34:54 300 16.784 g 2024-11-20T07:29:19 300 20.120 r 2024-11-20T07:34:47 300 19.922 The 7-Dimensional Telescope (7DT), comprising 20 wide-field telescopes equipped with 40 medium-bandwidth (~25nm) filters located in Chile, aims to detect optical counterparts of GW sources and conduct the 7-Dimensional Sky Survey (7DS) of the Southern Hemisphere. Further information about the 7DT is available at http://gwuniverse.snu.ac.kr/. View this GCN Circular online at https://gcn.nasa.gov/circulars/38610. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36610] EP241217b: Global MASTER-Net observations report
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38609 SUBJECT: EP241217b: Global MASTER-Net observations report DATE: 24/12/18 07:36:23 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP241217b ( EP Team et al., GCN 38606) errorbox 313 sec after notice time and 48497 sec after trigger time at 2024-12-18 06:26:21 UT, with upper limit up to 19.7 mag. The observations began at zenith distance = 28 deg. The sun altitude is -29.0 deg. The galactic latitude b = -26 deg., longitude l = 229 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2713458 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 48527 | 2024-12-18 06:26:21 | MASTER-OAFA | (05h 36m 52.07s , -25d 04m 22.7s) | C | 60 | 19.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38609. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36609] GRB 241209A: ATCA radio follow-up observations
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38608 SUBJECT: GRB 241209A: ATCA radio follow-up observations DATE: 24/12/18 07:11:43 GMT FROM: Tao An at SHAO, CAS <antao(a)shao.ac.cn> Tao An, Yuanqi Liu (SHAO), Jinjun Geng (PMO), and Xuefeng Wu (PMO) report on behalf of the Einstein Probe radio follow-up team: Following the detection of GRB 241209A by Fermi and Swift (Hamburg et al. 2024, GCN 38502; Evans et al. 2024, GCN 38523), we conducted radio follow-up observations using the Australia Telescope Compact Array (ATCA). We observed the VLT position [RA(J2000) = 10:21:35.14, Dec(J2000) = +06:19:44.5] during UTC 16:00:00-22:00:00 on December 14, 2024. No significant emission was detected at either 5.5 GHz or 9 GHz, yielding 3σ upper limits of 51 microJy and 36 microJy, respectively. We thank the ATCA team for their rapid scheduling and support. View this GCN Circular online at https://gcn.nasa.gov/circulars/38608. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36608] EP241217a: Xinglong optical follow-up observations
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38607 SUBJECT: EP241217a: Xinglong optical follow-up observations DATE: 24/12/18 07:04:57 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Junjie-Jin (NAOC), Yiming-Mao(NAOC), Zheng-Jie (NAOC), Haiyang-Mu(NAOC), Yinan-Zhu (NAOC), Qi-Zhao (NAOC), Feng-Xiao (NAOC), Zhou-Fan (NAOC), Hong-Wu (NAOC) report: We observed the field of the X-ray transient, EP 241217a by the Xinglong 0.8-m and 216 telescope located at Xinglong, Hebei, China. We obtained 6 x 600 s clear-band by 0.8-m telescop with a median time of 2024-12-17T10:12:27 , i.e., 5.5 hr after the EP trigger. We detected no optical object with the upper limit ～21 mag. Then we performed photometry on the Xinglong 2.16-m telescope located at Xinglong, Hebei, China, and obtained 6x600s clear-band frames with a median time of 2024-12-17T16:50:08 , i.e., 12 hr after the EP trigger. The optical object reported by Levan et al. (GCN #38587) is weakly detected in our image. We measure a preliminary magnitude of r = 21.4 +/- 0.14 mag (AB), calibrated against nearby stars from the Pan-STARRS catalog. We summarize our observation results as follows: Obs. No. | Time (UTC) | Exposure Time (s) | Filter | Apparent mag (AB) | Telescope Name 1 | 2024-12-17 10:12:27 | 6x600 s | Clear |> 21.0 | Xinglong 80-cm Telescope 2 | 2024-12-17 16:50:08 | 6x600 s | Clear | 21.4 +/- 0.14 | Xinglong 2.16-m Telescope View this GCN Circular online at https://gcn.nasa.gov/circulars/38607. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36607] EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38606 SUBJECT: EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion DATE: 24/12/18 06:20:25 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion H. Zhou (PMO, CAS), S.-F. Zhu (USTC), M. H. Zhang (NAO, CAS), C. C. Jin (NAO, CAS) report on behalf of the Einstein Probe team: We report on the detection of an X-ray transient by the Einstein Probe (EP), designated as EP241217b (Trigger ID: 01709129080). About 10 seconds after the trigger of GRB 241217A (GCN 38594), the Einstein Probe (EP) began to observe the scheduled field which happened to cover GRB 241217A. EP241217b triggered the on-board processing unit of the Wide-field X-ray Telescope (WXT) at 2024-12-17T16:58:04.349 (UTC), i.e., about 53 seconds after the trigger of GRB 241217A. The WXT position of the X-ray source is R.A. = 84.167 deg, Dec. = -25.281 deg, with an uncertainty of 2.8 arcmin (90%). About 134 seconds after the trigger of the GRB, the Follow-up X-ray Telescope (FXT) onborad EP performed an autonomous follow-up observation, and found an uncatalogued X-ray source, located at R.A., Dec. = 84.1499, -25.3003 deg with an uncertainty of about 20 arcsec (90%). The FXT position is consistent with the X-ray/optical afterglow positions of GRB 241217A (GCN 38594, 38599, 38600). EP241217b was detected by the WXT at the begining of the scheduled observation, i.e., 10 seconds after the GRB trigger. The WXT light curve (including the follow-up observation) clearly shows 2 pulses seperated in time. The first one lasts from 10 to 620s, and it is composed of two short pulses peaked at 150s and 260s, respectively (from 53 to 134 seconds, EP was slewing, the possiblity there could be other pulses in this period can not be ruled out). The second one lasts from 1000 to 1500s. The similar temporal behavior is also seen in the FXT light curve. The time averaged WXT spectrum (about 134 to 2000 seconds after the trigger of the GRB) was fitted by an absorbed powerlaw model with the fixed Milky Way equivalent hydrogen column density of 1.79 x 10^20 cm^-2 and an intrinsic absorber assuming the redshift of the absorper is 1.195 (the Legacy Survey dr9 photo-z of the extended source overlayed with EP241217b/GRB 241217A). The best fitted model shows the equivalent hydrogen column density of the intrinsic absorption is 1.42(-0.46, +0.51) x 10^22 cm^-2, the spectral index is 1.57(-0.21, +0.22) and the unabsorbed 0.5-4 keV flux is (1.19+/-0.10) x 10^-9 erg/s/cm^2. The FXT-A spectrum (about 134 to 7800 seconds after the triger of the GRB) is extracted with an annular region to mitigate the potential pile-up effect. The FXT spectrum is then fitted using the same model as the WXT spectrum. The best-fit intrinsic nH is 0.85(+/-0.06) x 10 ^ 22 cm^-2, with a power-law photon index of 1.58(+/-0.04). The unabsorbed 0.5-10 keV flux is measured at 1.1 x 10 ^-9 erg/s/cm^2. A further FXT follow-up observation has been arranged. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/38606. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36606] GRB 241218A: LCOGT Optical Upper Limit
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38605 SUBJECT: GRB 241218A: LCOGT Optical Upper Limit DATE: 24/12/18 04:35:43 GMT FROM: Robert Strausbaugh at Eastern Illinois University <rstrausbaugh(a)eiu.edu> R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the Swift GRB 241218A field (Williams et al., GCN 38601) with the LCOGT 1-meter Sinistro instrument at the Teide Tenerife site, on December 18, from 03:45 to 04:17 UT (corresponding to 3.62 to 4.15 hours after the GRB trigger time) with the sdss r and i filters. We performed a series of 3x300s exposures in i-band and r-band. We do not detect a source within the Swift XRT enhanced error region (Beardmore et al., GCN 38604) in either band. The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference: r > 21.2 i > 20.9 These magnitudes are not corrected for galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38605. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36605] GRB 241218A: Enhanced Swift-XRT position
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38604 SUBJECT: GRB 241218A: Enhanced Swift-XRT position DATE: 24/12/18 03:21:43 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 1225 s of XRT Photon Counting mode data and 2 UVOT images for GRB 241218A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 185.68168, +29.97318 which is equivalent to: RA (J2000): 12h 22m 43.60s Dec (J2000): +29d 58' 23.5" with an uncertainty of 2.4 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38604. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36604] EP241217a: Global MASTER-Net observations report
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38603 SUBJECT: EP241217a: Global MASTER-Net observations report DATE: 24/12/18 03:18:36 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP241217a ( EP Team et al., GCN 38586) errorbox 26048 sec after notice time and 70566 sec after trigger time at 2024-12-18 01:12:09 UT, with upper limit up to 20.0 mag. The observations began at zenith distance = 63 deg. The sun altitude is -17.7 deg. The galactic latitude b = -23 deg., longitude l = 155 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2712866 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 70597 | 2024-12-18 01:12:09 | MASTER-OAFA | (03h 07m 45.73s , +30d 58m 27.8s) | C | 60 | 15.7 | 70657 | 2024-12-18 01:12:09 | MASTER-OAFA | (03h 07m 45.73s , +30d 58m 27.6s) | C | 180 | 18.3 | Coadd 70798 | 2024-12-18 01:15:31 | MASTER-OAFA | (03h 07m 46.25s , +30d 56m 36.0s) | C | 60 | 18.1 | 71479 | 2024-12-18 01:26:51 | MASTER-OAFA | (03h 07m 45.08s , +30d 57m 01.2s) | C | 60 | 18.0 | 71678 | 2024-12-18 01:30:10 | MASTER-OAFA | (03h 07m 48.27s , +30d 58m 57.0s) | C | 60 | 17.3 | 71738 | 2024-12-18 01:30:10 | MASTER-OAFA | (03h 07m 48.28s , +30d 58m 57.0s) | C | 180 | 18.3 | Coadd 72347 | 2024-12-18 01:41:19 | MASTER-OAFA | (03h 07m 47.62s , +30d 59m 09.1s) | C | 60 | 16.8 | 72549 | 2024-12-18 01:44:42 | MASTER-OAFA | (03h 07m 50.77s , +30d 59m 13.3s) | C | 60 | 18.4 | 73299 | 2024-12-18 01:57:11 | MASTER-OAFA | (03h 07m 43.89s , +30d 59m 05.1s) | C | 60 | 18.1 | 73359 | 2024-12-18 01:57:11 | MASTER-OAFA | (03h 07m 43.89s , +30d 59m 05.0s) | C | 180 | 19.5 | Coadd 74047 | 2024-12-18 02:09:39 | MASTER-OAFA | (03h 07m 42.54s , +31d 00m 30.4s) | C | 60 | 19.0 | 74252 | 2024-12-18 02:13:05 | MASTER-OAFA | (03h 07m 42.12s , +30d 58m 38.0s) | C | 60 | 18.8 | 74845 | 2024-12-18 02:22:57 | MASTER-OAFA | (03h 07m 48.62s , +30d 59m 56.1s) | C | 60 | 19.6 | 74905 | 2024-12-18 02:22:57 | MASTER-OAFA | (03h 07m 48.62s , +30d 59m 56.1s) | C | 180 | 20.0 | Coadd 75177 | 2024-12-18 02:28:30 | MASTER-OAFA | (03h 07m 48.54s , +30d 59m 10.1s) | C | 60 | 19.1 | 75669 | 2024-12-18 02:36:42 | MASTER-OAFA | (03h 07m 42.11s , +31d 00m 20.4s) | C | 60 | 19.0 | 76004 | 2024-12-18 02:42:16 | MASTER-OAFA | (03h 07m 47.92s , +31d 00m 30.0s) | C | 60 | 19.1 | 76064 | 2024-12-18 02:42:16 | MASTER-OAFA | (03h 07m 47.92s , +31d 00m 30.0s) | C | 180 | 19.8 | Coadd 76821 | 2024-12-18 02:55:53 | MASTER-OAFA | (03h 07m 43.45s , +31d 00m 04.7s) | C | 60 | 19.2 | 77238 | 2024-12-18 03:02:51 | MASTER-OAFA | (03h 07m 40.33s , +31d 02m 00.4s) | C | 60 | 19.2 | 77567 | 2024-12-18 03:08:20 | MASTER-OAFA | (03h 07m 38.60s , +31d 00m 08.7s) | C | 60 | 18.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38603. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36603] EP241217a: Global MASTER-Net observations report
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38603 SUBJECT: EP241217a: Global MASTER-Net observations report DATE: 24/12/18 03:18:36 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP241217a ( EP Team et al., GCN 38586) errorbox 26048 sec after notice time and 70566 sec after trigger time at 2024-12-18 01:12:09 UT, with upper limit up to 20.0 mag. The observations began at zenith distance = 63 deg. The sun altitude is -17.7 deg. The galactic latitude b = -23 deg., longitude l = 155 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2712866 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 70597 | 2024-12-18 01:12:09 | MASTER-OAFA | (03h 07m 45.73s , +30d 58m 27.8s) | C | 60 | 15.7 | 70657 | 2024-12-18 01:12:09 | MASTER-OAFA | (03h 07m 45.73s , +30d 58m 27.6s) | C | 180 | 18.3 | Coadd 70798 | 2024-12-18 01:15:31 | MASTER-OAFA | (03h 07m 46.25s , +30d 56m 36.0s) | C | 60 | 18.1 | 71479 | 2024-12-18 01:26:51 | MASTER-OAFA | (03h 07m 45.08s , +30d 57m 01.2s) | C | 60 | 18.0 | 71678 | 2024-12-18 01:30:10 | MASTER-OAFA | (03h 07m 48.27s , +30d 58m 57.0s) | C | 60 | 17.3 | 71738 | 2024-12-18 01:30:10 | MASTER-OAFA | (03h 07m 48.28s , +30d 58m 57.0s) | C | 180 | 18.3 | Coadd 72347 | 2024-12-18 01:41:19 | MASTER-OAFA | (03h 07m 47.62s , +30d 59m 09.1s) | C | 60 | 16.8 | 72549 | 2024-12-18 01:44:42 | MASTER-OAFA | (03h 07m 50.77s , +30d 59m 13.3s) | C | 60 | 18.4 | 73299 | 2024-12-18 01:57:11 | MASTER-OAFA | (03h 07m 43.89s , +30d 59m 05.1s) | C | 60 | 18.1 | 73359 | 2024-12-18 01:57:11 | MASTER-OAFA | (03h 07m 43.89s , +30d 59m 05.0s) | C | 180 | 19.5 | Coadd 74047 | 2024-12-18 02:09:39 | MASTER-OAFA | (03h 07m 42.54s , +31d 00m 30.4s) | C | 60 | 19.0 | 74252 | 2024-12-18 02:13:05 | MASTER-OAFA | (03h 07m 42.12s , +30d 58m 38.0s) | C | 60 | 18.8 | 74845 | 2024-12-18 02:22:57 | MASTER-OAFA | (03h 07m 48.62s , +30d 59m 56.1s) | C | 60 | 19.6 | 74905 | 2024-12-18 02:22:57 | MASTER-OAFA | (03h 07m 48.62s , +30d 59m 56.1s) | C | 180 | 20.0 | Coadd 75177 | 2024-12-18 02:28:30 | MASTER-OAFA | (03h 07m 48.54s , +30d 59m 10.1s) | C | 60 | 19.1 | 75669 | 2024-12-18 02:36:42 | MASTER-OAFA | (03h 07m 42.11s , +31d 00m 20.4s) | C | 60 | 19.0 | 76004 | 2024-12-18 02:42:16 | MASTER-OAFA | (03h 07m 47.92s , +31d 00m 30.0s) | C | 60 | 19.1 | 76064 | 2024-12-18 02:42:16 | MASTER-OAFA | (03h 07m 47.92s , +31d 00m 30.0s) | C | 180 | 19.8 | Coadd 76821 | 2024-12-18 02:55:53 | MASTER-OAFA | (03h 07m 43.45s , +31d 00m 04.7s) | C | 60 | 19.2 | 77238 | 2024-12-18 03:02:51 | MASTER-OAFA | (03h 07m 40.33s , +31d 02m 00.4s) | C | 60 | 19.2 | 77567 | 2024-12-18 03:08:20 | MASTER-OAFA | (03h 07m 38.60s , +31d 00m 08.7s) | C | 60 | 18.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38603. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36602] GRB 241217A: GMG Optical Upper Limit
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38602 SUBJECT: GRB 241217A: GMG Optical Upper Limit DATE: 24/12/18 02:36:17 GMT FROM: Rui-Zhi Li at Yunnan Observatories, CAS <liruizhi(a)ynao.ac.cn> R.-Z. Li, B.-T. Wang, F.-F. Song, J. Mao, H.-C. Feng and J.-M. Bai (YNAO, CAS) report: We observed the field of GRB 241217A (Marius et al., GCN 38594, T0 at 2024-12-17T16:57:13) using the GMG-2.4m telescope at the Lijiang Observatory. The observation began at 2024-12-17T17:30:55, about 0.56 hours after the trigger. No new uncataloged optical source was detected within the SVOM/VT error circle (GCN 38600). The preliminary analysis results are shown as follows: +----------------+------------+----------+----------------+ | Tmid-T0 [hr] | Exp. [s] | Filter | 5-sigma U.L. | +================+============+==========+================+ | 0.65 | 600 | r | 20.6 | +----------------+------------+----------+----------------+ The given magnitudes are derived based on calibrating against Pan-STARRS1 field stars. View this GCN Circular online at https://gcn.nasa.gov/circulars/38602. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36601] GRB 241218A: Swift detection of a burst
by GCN Circulars 18 Dec '24

18 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38601 SUBJECT: GRB 241218A: Swift detection of a burst DATE: 24/12/18 00:58:22 GMT FROM: Boris Sbarufatti at INAF-OAB <boris.sbarufatti(a)inaf.it> M. A. Williams (PSU), R. Gupta (NASA GSFC), N. P. M. Kuin (UCL-MSSL), B. Sbarufatti (INAF-OAB) and A. Tohuvavohu (Caltech) report on behalf of the Neil Gehrels Swift Observatory Team: At 00:08:51 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 241218A (trigger=1275005). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 185.682, +29.991 which is RA(J2000) = 12h 22m 44s Dec(J2000) = +29d 59' 27" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 25 sec. The peak count rate was ~896 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 00:11:15.6 UT, 144.5 seconds after the BAT trigger. The position determined from promptly downlinked data differs significantly from the on-board position, suggesting that the XRT may have centroided on a cosmic ray; the initial XRT position notice should be treated with caution. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 185.68146, 29.97303 which is equivalent to: RA(J2000) = 12h 22m 43.55s Dec(J2000) = +29d 58' 22.9" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 64 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.23 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 151 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.023. Burst Advocate for this burst is M. A. Williams (mjw6837 AT psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/38601. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36600] GRB 241217A : SVOM/VT optical afterglow detection
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38600 SUBJECT: GRB 241217A : SVOM/VT optical afterglow detection DATE: 24/12/17 23:42:59 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Y. L. Qiu, H. L. Li, L. P. Xin (NAOC), D. B. Malesani (DAWN/NBI and Radboud Univ.), S. D. Vergani (Obs.Paris), J. T. Palmerio (CEA), M. Brunet (IRAP), D. Turpin (CEA),C. Wu, X. H. Han, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. Deng, L. Lan, X. M. Lu, R. S. Zhang (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM), H. Zhou (PMO)，R. Z. Li (YNAO) report on behalf of the SVOM team: GRB 241217A (Brunet et al., GCN circular 38594) was observed by on-board SVOM/VT after the automatic slew of the satellite. The VT conducted observations in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously. With the downlinked X band data an uncatalogued optical source was detected in stacked images in both VT_B and VT_R bands within the error box of SVOM/ECLAIRs (6.8 arcmin radius at 90% C.L.), SVOM/MXT (25 arcsec radius at 90% C.L.), compared to the DESI Dr10 catalog. The source is located at RA, Dec = 84.1513626, -25.2970374, which is equivalent to: RA (J2000) : 05:36:36.327 Dec (J2000): -25:17:49.33 with an uncertainty of 0.5 arcsec. This source overlaps a faint extended source visible in archival DESI images of the field. This position is consistent with the X-ray counterpart position of Swift/XRT reported by Williams et al. (GCN 38599). The light curve of the counterpart in VT_R decayed from 240 s to 500 s after the burst and then a re-brightening occurred with a maximum at around 1000 s and then re-decayed. The magnitude was VT_B=22.4, VT_R=21.4 mag in AB magnitude about 300 seconds after the trigger. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC),CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/38600. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36599] GRB 241217A: Swift-XRT afterglow detection
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38599 SUBJECT: GRB 241217A: Swift-XRT afterglow detection DATE: 24/12/17 23:30:07 GMT FROM: Maia Williams at PSU <mjw6837(a)psu.edu> M. A. Williams (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), S. Dichiara (PSU), J.A. Kennea (PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected burst GRB 241217A. We searched for X-ray sources in 1.4 ks of Photon Counting (PC) mode data. The total exposure at the position of the afterglow (see below) is 1.4 ks, obtained between T0+2.2 ks and T0+7.6 ks. An uncatalogued X-ray source is detected within the estimated 3-sigma SVOM/ECLAIRs error region (6.8 arcmin) and is above the RASS 3-sigma upper limit at this position and fading with 5.3 sigma significance, and is therefore likely the GRB afterglow. Using 1404 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 84.15110, -25.29680 which is equivalent to: RA (J2000): 05h 36m 36.26s Dec(J2000): -25d 17' 48.5" with an uncertainty of 2.5 arcsec (radius, 90% confidence). This position is 1.7 arcmin from the SVOM/ECLAIRs position. The peak count rate is 36 (±6) ct s^-1 (0.3 - 10 keV). View this GCN Circular online at https://gcn.nasa.gov/circulars/38599. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36598] GRB 241217A: LCO optical upper limit
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38598 SUBJECT: GRB 241217A: LCO optical upper limit DATE: 24/12/17 21:41:05 GMT FROM: Damien Turpin at CEA-Saclay <dturpin-astro(a)hotmail.com> D. Turpin, J. T. Palmerio (CEA/Irfu), S. Vergani (GEPI/Obs. de Paris), A. Saccardi (CEA/Irfu), S. Basa (UAR Pytheas, OHP, LAM), E. Le Floc'h (CEA Paris-Saclay, DAp/AIM), L.-P Xin (NAOC) on behalf of a larger collaboration. We observed the field of GRB 241217A detected by SVOM (Brunet et al., GCN 38594) with the LCO 1.0m telescope at the Sutherland Observatory (SAAO) equipped with the Sinistro instrument. Our observation started at 2024-12-17 19:17:34.013 UTC (T - TGRB ~ 2.3 h) with 4 x 180s exposure using the sdss-r filter. Despite good weather conditions, we note a slightly loss of telescope tracking during our single exposures which reduced a bit our image quality. We did not detect any uncatalogued optical source inside the refined SVOM/MXT afterglow candidate position (Brunet et al., GCN 37594). In our first image, we derived the preliminary following upper limit (3 sigma, AB system) calibrated with the PanSTARRS DR1 catalog and not corrected from the galactic extinction E(B-V): 0.03: Tmid-T0 | mag (AB) | filter | ------------------------------ 2.36h |21.6 (U.L.)| sdssr | This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101004719 View this GCN Circular online at https://gcn.nasa.gov/circulars/38598. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36597] GRB 241217A: GRANDMA/TAROT optical upperlimits
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38597 SUBJECT: GRB 241217A: GRANDMA/TAROT optical upperlimits DATE: 24/12/17 21:12:07 GMT FROM: Thomas Hussenot-Desenonges at IJCLab <thomas.hussenot(a)ijclab.in2p3.fr> T. Hussenot-Desenonges (IJCLAB), L. De Almeida, W. Corradi, N. Sasaki, F. Navarete (LNA), H. Peng (THU), H. Lau Jun Xian (Tsinghua Univ.), A. Klotz (IRAP), S. Antier (OCA), C. Andrade (UMN), S. Karpov (FZU), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), N. Guessoum (AUS), on behalf of the GRANDMA collaboration: We observed the field of GRB 241217A, detected by SVOM/ECLAIRs (GCN 38594) using TAROT/TRE. Observations (unfiltered) began at 2024-12-17T17:22:00UTC, 19 min after T0 and continued up to 45 min after T0. We did not detect any optical afterglow candidate in our stacked images within a 5-sigma upper limit of r > 18.1 (AB magnitude, calibrated with PanSTARRS). All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). View this GCN Circular online at https://gcn.nasa.gov/circulars/38597. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36596] EP241217a: Swift-XRT Detection
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38596 SUBJECT: EP241217a: Swift-XRT Detection DATE: 24/12/17 18:53:37 GMT FROM: Maia Williams at PSU <mjw6837(a)psu.edu> M. A. Williams (PSU), M. H. Siegel (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), S. Dichiara (PSU), and P.A. Evans (U. Leicester) report on behalf of the Swift team: Swift-XRT has performed follow-up observations of the Einstein Probe/WXT-detected X-ray transient EP241217a. We searched for X-ray sources in 1.6 ks of Photon Counting (PC) mode data. The total exposure at the position of the transient (see below) is 1.537 ks, obtained between T0+24.2 ks and T0+25.7 ks. An uncatalogued X-ray source is detected within the estimated 90% EP/FXT error region (20 arcsec) and is believed to be associated with the EP source (GCN Circ. 38586). Using 1537 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 46.94156, +30.92977 which is equivalent to: RA (J2000): 03h 07m 45.98s Dec(J2000): +30d 55' 47.2" with an uncertainty of 4.1 arcsec (radius, 90% confidence). This position is 0.091 arcmin from the EP/FXT position and 3.2 arcsec from the optical counterpart reported by Levan et al. (GCN Circ. 38587). The peak count rate is 0.039 (+0.007, -0.006) ct s-1 (0.3 — 10 keV), which suggests fading from the EP/WXT detection. The observed 0.3-10 keV flux is 1.5 (+0.7, -0.3) × 10-12 erg cm-2 s-1. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.7 (+0.5, -0.4). The best-fitting absorption column is 1.9 x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.89 × 10^-11 (4.99 × 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic column: 1.9 x 10^21 cm^-2 Photon index: 1.7 (+0.5, -0.4) The Swift/UVOT began settled observations of the field of EP 241217a 24.3 ks after the EP trigger. A 1639s image taken in the u filter shows no optical transient at the XRT position down to a limit of u=20.83. We show no source consistent with that reported by Levan et al. (GCN Circ. 38587), Izzo et al. (GCN Circ. 38588), and Fan et al. (GCN Circ 38592). The lack of UVOT detection would be consistent with the redshift of z=4.6 reported by Levan et al. (GCN Circ. 38593). View this GCN Circular online at https://gcn.nasa.gov/circulars/38596. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36595] EP241217A: Non-detection from Fermi-GBM Observations
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38595 SUBJECT: EP241217A: Non-detection from Fermi-GBM Observations DATE: 24/12/17 18:40:57 GMT FROM: mariaedvige.ravasio(a)ru.nl M. E. Ravasio (Radboud Univ.), E. Burns (LSU), and P.G. Jonker (Radboud Univ.) report on behalf of the Fermi-GBM Team: The location of the EP-WXT event EP241217A (Zhou et al., GCN 38586) was occulted by the Earth at the EP trigger time T0=2024-12-17T05:36:03 UTC. There was no Fermi-GBM onboard trigger around the EP-WXT trigger time. The location becomes visible at around ~T0+104 s. The GBM targeted search [1], the most sensitive, coherent search for GRB-like signals, was run in the time interval [-50;+500] s from the EP trigger time, seeking signals between 64 ms and 32.768 s in duration. A long soft transient was found around T0-42 s, but its localization is not consistent with the EP transient’s one (which is still covered by the Earth at that time). No signal consistent both temporally and spatially is identified, as confirmed by visual inspection of the data. [1] Goldstein et al. 2019 arXiv:1903.12597 View this GCN Circular online at https://gcn.nasa.gov/circulars/38595. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36594] GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38594 SUBJECT: GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate DATE: 24/12/17 17:43:20 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Brunet Marius, Fortin Francis (IRAP), Turpin Damien, Stéphane Schanne, Clara Plasse (CEA), Frédéric Piron (LUPM), Shi-Jie Zheng (IHEP) report on behalf of the SVOM team: During the commissioning phase, the SVOM/ECLAIRs telescope triggered and located the long duration GRB 241217A (sb24121704) starting at 2024-12-17T16:57:13 UTC (Tb). The following trigger information was received on the ground with low-latency by the SVOM VHF Alert Network. The burst was detected by both the on-board Count-Rate Trigger (CRT) and Image Trigger (IMT) and 9 alerts were received. The best detection is obtained by IMT with a signal-to-noise ratio of 11.9 in the 8-120 keV energy band over a time window of 82 s starting at Tb. The light light curve shows multiple broad peaks in 5-50 keV in ECLAIRs and below 550 keV in GRM. The localization of the best Alert is RA, Dec = 84.160, -25.324 (J2000). The statistical uncertainty on this position is 6.8 arcminutes, which includes a systematic uncertainty of 2 arcminutes in quadrature. SVOM slewed automatically on this burst. MXT began observing the field at 2024-17-12T17:01:36, 263 seconds after Tb. Using onboard processed data we found one very bright uncatalogued X-ray source located at RA, Dec 84.152, -25.295 degrees with a 90% C.L. radius of 25 arcsec (statistic + systematic), corresponding to: R.A. = 05h 36m 36s Dec = -25° 17' 42'' This location is 1.8 arcminutes from the ECLAIRs onboard position. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. The SVOM point of contact for this burst is: Brunet Marius (marius.brunet(a)irap.omp.eu) View this GCN Circular online at https://gcn.nasa.gov/circulars/38594. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36593] GRB 241217A : SVOM/ECLAIRs detection of a long burst with bright X-ray afterglow candidate
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38594 SUBJECT: GRB 241217A : SVOM/ECLAIRs detection of a long burst with bright X-ray afterglow candidate DATE: 24/12/17 17:43:20 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Brunet Marius, Fortin Francis (IRAP), Turpin Damien, Stéphane Schanne, Clara Plasse (CEA), Frédéric Piron (LUPM), Shi-Jie Zheng (IHEP) report on behalf of the SVOM team: During the commissioning phase, the SVOM/ECLAIRs telescope triggered and located the long duration GRB 241217A (sb24121704) starting at 2024-12-17T16:57:13 UTC (Tb). The following trigger information was received on the ground with low-latency by the SVOM VHF Alert Network. The burst was detected by both the on-board Count-Rate Trigger (CRT) and Image Trigger (IMT) and 9 alerts were received. The best detection is obtained by IMT with a signal-to-noise ratio of 11.9 in the 8-120 keV energy band over a time window of 82 s starting at Tb. The light light curve shows multiple broad peaks in 5-50 keV in ECLAIRs and below 550 keV in GRM. The localization of the best Alert is RA, Dec = 84.160, -25.324 (J2000). The statistical uncertainty on this position is 6.8 arcminutes, which includes a systematic uncertainty of 2 arcminutes in quadrature. SVOM slewed automatically on this burst. MXT began observing the field at 2024-17-12T17:01:36, 263 seconds after Tb. Using onboard processed data we found one very bright uncatalogued X-ray source located at RA, Dec 84.152, -25.295 degrees with a 90% C.L. radius of 25 arcsec (statistic + systematic), corresponding to: R.A. = 05h 36m 36s Dec = -25° 17' 33" This location is 1.8 arcminutes from the ECLAIRs onboard position. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. The SVOM point of contact for this burst is: Brunet Marius (marius.brunet(a)irap.omp.eu) View this GCN Circular online at https://gcn.nasa.gov/circulars/38594. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36592] EP241217a: Gemini-North spectroscopic redshift z = 4.59
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38593 SUBJECT: EP241217a: Gemini-North spectroscopic redshift z = 4.59 DATE: 24/12/17 16:27:32 GMT FROM: Andrew Levan at Radboud University <a.levan(a)astro.ru.nl> A. J. Levan (Radboud/Warwick), J. A. Quirola-Vasquez (Radboud), J. C. Rastinejad (Northwestern), D. B. Malesani (DAWN/NBI & Radboud), P. G. Jonker (Radboud), A. Martin-Carrillo (UCD) report for a larger collaboration: Following the detection of EP241217a (Zhou et al. GCN 38586) and its optical counterpart (Levan et al., GCN 38587; Izzo & Malesani, GCN 38588, Fan et al. GCN 38592) we obtained 1600 s of optical spectroscopy with GMOS-N on Gemini-N and the R400 grating. Spectra cover the range ~5500-9500 AA. A preliminary reduction of the data shows a bright continuum with a strong break at ~6820 AA, along with several narrow absorption lines, which we interpret as due to Si II, C II, weak C IV, Fe II, Al II, all at a common redshift of z = 4.59 (based on a provisional wavelength calibration). We suggest this is the redshift of EP241217a. We thank the staff of Gemini-North for the rapid execution of these observations. This work made use of the GRBspec database at http://grbspec.eu (de Ugarte Postigo et al. 2014, doi:10.1117/12.2055774). View this GCN Circular online at https://gcn.nasa.gov/circulars/38593. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36591] EP241217a: Kinder optical follow-up observations
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38592 SUBJECT: EP241217a: Kinder optical follow-up observations DATE: 24/12/17 16:21:16 GMT FROM: Janet Chen at National Central University <janetstars(a)gmail.com> L. L. Fan (HNAS), A. Aryan, T.-W. Chen, H.-Y. Hsiao (all NCU), A. K. H. Kong (NTHU), J. Gillanders (Oxford), K. W. Smith, S. J. Smartt (Oxford/QUB), A. Sankar.K, Y.-H. Lee, H.-Y. Miao, Y. J. Yang, M.-H. Lee, W.-J. Hou, C.-C. Ngeow, Y.-C. Pan, C.-H. Lai, H.-C. Lin, C.-S. Lin, J.-K. Guo (all NCU), Z. N. Wang, S. Yang, G. H. Sun (all HNAS), H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, L. Rhodes (all Oxford), M. Nicholl, M. Fulton, T. Moore, C. Angus, A. Aamer (all QUB), A. Schultz and M. Huber (both IfA, Hawaii) report: We observed the field of the fast X-ray transient EP241217a (Zhou et al., GCN 38586) using the Lulin One-meter Telescope (LOT) at Lulin Observatory in Taiwan as part of the Kinder collaboration (Chen & Yang et al., 2024; arXiv:2406.09270). The first LOT epoch of observations started at 12:56 UT on the 17th of December 2024 (MJD 60661.539), 7.34 hr after the EP trigger. We utilized the astroalign (Beroiz et al., 2020, A&C, 32, 100384) and astropy (Astropy Collaboration et al., 2022, ApJ, 935, 167) packages to align and stack the individual frames. In the stacked frame, we clearly detected the optical counterpart candidate proposed by Levan et al. (GCN 38587), and also observed by Izzo et al. (GCN 38588). Further, we utilized the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform PSF photometry on our stacked frames. The details of the observations and measured PSF magnitudes (in the AB system) of the possible counterpart of EP241217a are as follows: Telescope | Filter | MJD (start) | t-t0 (hr) | Exposure (s) | Magnitude | avg. Seeing | med. Airmass LOT | r | 60661.539 | 7.34 | 300 * 15 | 21.24 +/- 0.33 | 1".55 | 1.01 The presented magnitude was calibrated using the field stars from the Pan-STARRS1 catalog and was not corrected for the expected Galactic foreground extinction corresponding to a reddening of A_r = 0.52 mag in the direction of the burst (Schlafly & Finkbeiner 2011). View this GCN Circular online at https://gcn.nasa.gov/circulars/38592. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36590] GRB 241214A: GRBAlpha detection
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38591 SUBJECT: GRB 241214A: GRBAlpha detection DATE: 24/12/17 15:42:28 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 241214A (SVOM/GRM detection: GCN 38578; Swift/BAT-GUANO detection: GCN 38582; Konus/Wind detection trigger at 2024-12-14 03:24:37.630 UTC; INTEGRAL/SPI-ACS peak detection at 2024-12-14 ~03:24:32 UTC) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2024-12-14 03:24:33.5 UTC. The T90 duration measured by GRBAlpha is 2.5 s and the overall significance during T90 reaches 11 sigma. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB241214A_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. View this GCN Circular online at https://gcn.nasa.gov/circulars/38591. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36589] GRB 241213A (EP241213a): GRBAlpha detection
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38590 SUBJECT: GRB 241213A (EP241213a): GRBAlpha detection DATE: 24/12/17 15:41:39 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 241213A (Swift/BAT detection: GCN 38547; EP/WXT detection: GCN 38554; INTEGRAL/SPI-ACS detection: GCN 38556; Konus/Wind detection: GCN 38581) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2024-12-13 02:19:00.5 UTC. The T90 duration measured by GRBAlpha is 4.5 s and the overall significance during T90 reaches 7.6 sigma. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB241213A_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. View this GCN Circular online at https://gcn.nasa.gov/circulars/38590. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36588] GRB 241209D: GRBAlpha detection
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38589 SUBJECT: GRB 241209D: GRBAlpha detection DATE: 24/12/17 14:24:14 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 241209D (Fermi/GBM detection: GCN 38488; Swift/BAT detection: GCN 38489; AstroSat/CZTI detection: GCN 38518; Konus/Wind detection: GCN 38526; CALET/CGBM detection: GCN 38569) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2024-12-09 10:59:45.2 UTC. The T90 duration measured by GRBAlpha is 52 s and the overall significance during T90 reaches 11 sigma. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB241209D_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. View this GCN Circular online at https://gcn.nasa.gov/circulars/38589. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36587] EP241217A: LCO optical observations
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38588 SUBJECT: EP241217A: LCO optical observations DATE: 24/12/17 11:17:46 GMT FROM: luca.izzo(a)inaf.it L. Izzo (INAF-OACn and DARK/NBI), and D. B. Malesani (DAWN/NBI and Radboud Univ.) report: We observed the field of EP241217A (Zhou et al., GCN #38586) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at the MacDonald Observatory, TX, USA. Observations started on 2024 December 17 at 06:37 UT (1.02 hr after the EP trigger). We obtained a series of 3x180 s images in the SDSS-r filter. The optical object reported by Levan et al. (GCN #38587) is weakly detected in our image. We measure a preliminary magnitude of r = 20.99 +/- 0.21 mag (AB), calibrated against nearby stars from the Pan-STARRS catalog. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719. We also acknowledge the use of the ECSnoopy package by E. Cappellaro. View this GCN Circular online at https://gcn.nasa.gov/circulars/38588. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36586] EP241217a: Gemini-North detection of the likely optical counterpart
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38587 SUBJECT: EP241217a: Gemini-North detection of the likely optical counterpart DATE: 24/12/17 11:04:54 GMT FROM: Andrew Levan at Radboud University <a.levan(a)astro.ru.nl> A. J. Levan (Radboud/Warwick), J. C. Rastinejad (Northwestern), D. B. Malesani (DARK/NBI & Radboud), P. G. Jonker (Radboud), J. A. Quirola-Vasquez (Radboud) report for a larger collaboration: We obtained observations of EP241217a (Zhou et al., GCN 38586) with the GMOS instrument on the Gemini North telescope. Observations in the z band began at 08:04 UT, approximately 2.5 hr after the EP-WXT detection. Within the EP-FXT error circle (Zhou et al., GCN 38586) we clearly identify a new source, not present in the Pan-STARRS imaging of the field, with an approximate magnitude of z ~ 19.9 and a position of RA(J2000) = 03:07:46.20 DEC(J2000) = +30:55:45.9 with an uncertainty of <0.5". We suggest this is the optical counterpart of EP241217a. We thank the staff of Gemini for rapidly obtaining these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/38587. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36585] EP241217a: EP detection of an X-ray transient
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38586 SUBJECT: EP241217a: EP detection of an X-ray transient DATE: 24/12/17 08:50:44 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> H. Zhou (PMO, CAS), R. D. Liang (NAO, CAS), S.-F. Zhu (USTC), Z. X. Ling (NAO, CAS) report on behalf of the Einstein Probe team: We report on the detection of an X-ray transient by the Einstein Probe (EP), designated as EP241217a (Trigger ID: 01709129076). The source triggered the on-board processing unit of the Wide-field X-ray Telescope (WXT) at 2024-12-17T05:36:03 (UTC). The WXT position of the transient is R.A. = 46.957 deg, Dec. = 30.901 deg, with an uncertainty of 2.8 arcmin (90%). No previously known bright X-ray sources are found within the error circle around the transient position. The Follow-up X-ray Telescope (FXT) onborad EP performed an autonomous follow-up observation and found an uncatalogued X-ray source, located at R.A., Dec. = 46.9398, 30.9299 deg with an uncertainty of about 20 arcsec (90%). More information will be updated when the telemetry data is received. The ZTF and PANSTARR images show there are one point source and an extended source within the 90% unceratinty of the localization, and the distances to the FXT position are about 18.9" and 9.7", respectively. Further observations are encouraged to explore the origin of EP241217a. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/38586. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36584] The EP-WXT trigger 01709129023 is likely a flaring star
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38585 SUBJECT: The EP-WXT trigger 01709129023 is likely a flaring star DATE: 24/12/17 08:24:58 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> S.-F. Zhu (USTC), H. Zhou (PMO, CAS), R. D. Liang (NAO, CAS), Z. X. Ling (NAO, CAS) report on behalf of the Einstein Probe team: The EP-WXT trigger (ID 01709129023) on 2024-12-16T09:39:05 (UTC) is likely a stellar flare associated with an eruptive variable UCAC4 797-019583. The estimated flux of the flare is around 1.8 x 10^-10 erg/s/cm^2 in 0.5-4 keV, corresponding to an X-ray luminosity of around 6 x 10^31 erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with onboard X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/38585. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36583] EP241107a: VLA Radio Observation
by GCN Circulars 17 Dec '24

17 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38584 SUBJECT: EP241107a: VLA Radio Observation DATE: 24/12/17 05:50:15 GMT FROM: Arvind Balasubramanian <arvind6895(a)gmail.com> A. Balasubramanian (IIA), D. Eappachen (IIA), G.C. Anupama (IIA), V. Bhalerao (IITB) and D. K. Sahu (IIA) report: We observed the field of the fast X-ray transient EP241107a (Zhou et al., GCN 38112) with Karl G. Jansky Very Large Array (VLA) under the DDT (PI: A. Balasubramanian, 24B-492) on 1st December 2024 in band C (6 GHz) for about 30 minutes starting at 00:38 hours UTC. We detect a point radio source at 02h20m02.4s +03d20m01.6s. We used 3C147 for the flux calibration and J0239-025 for complex gain and phase calibration. The CASA-VLA calibration and imagining pipeline 6.5.4.9 was used for data calibration and imaging. We compute the flux density of the radio source to be 207±7 µJy. There is no previously reported source in the radio catalogues at the position of this source. We thank the TAC and operations team of VLA for making these observations possible. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. View this GCN Circular online at https://gcn.nasa.gov/circulars/38584. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36582] GRB 241213A: Swift-BAT refined analysis
by GCN Circulars 16 Dec '24

16 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38583 SUBJECT: GRB 241213A: Swift-BAT refined analysis DATE: 24/12/16 20:57:10 GMT FROM: Takanori Sakamoto at AGU <tsakamoto(a)phys.aoyama.ac.jp> T. Sakamoto (AGU), S. D. Barthelmy (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 241213A (trigger #1274039) (Gupta, et al., GCN Circ. 38547). The BAT ground-calculated position is RA, Dec = 116.163, 35.269 deg which is RA(J2000) = 07h 44m 39.2s Dec(J2000) = +35d 16' 06.7" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 44%. The mask-weighted light curve shows a single bright episode that starts at ~T-11 s, peaks at ~T+1 s and ends at ~T+16 s. T90 (15-350 keV) is 10.3 +- 3.1 sec (estimated error including systematics). The time-averaged spectrum from T-10.79 to T+16.54 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.26 +- 0.06. The fluence in the 15-150 keV band is 4.1 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.24 sec in the 15-150 keV band is 10.3 +- 0.5 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1274039 View this GCN Circular online at https://gcn.nasa.gov/circulars/38583. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36581] GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
by GCN Circulars 16 Dec '24

16 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38582 SUBJECT: GRB 241214A: Swift/BAT-GUANO localization skymap of a burst DATE: 24/12/16 17:57:32 GMT FROM: Jimmy DeLaunay at Penn State <delauj2(a)gmail.com> James DeLaunay (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (Caltech), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT did not localize GRB 241214A onboard (T0: 2024-12-14T03:24:32.90 UTC, SVOM/GRM trig sb24121401 GCN 38578) The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 90 seconds of BAT event-mode data from [-45,+45] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 30.1 in a 2.048 s analysis time bin, starting at T0 - 1.536 s. Using the NITRATES analysis, parameter estimation was performed to obtain the localization of this burst in the form of a HEALPIX Multi-Order Coverage (MOC) skymap. This localization accounts for both statistical and systematic errors. More details in the creation and calibration of these maps will soon be published (DeLaunay et al. 2025. in prep) The 90% credible area is 1,216 deg2 and the 50% credible area is 377 deg2. The integrated probability inside the coded field of view is <1%. A plot of the probability skymap can be viewed here: [skymap_plot](https://guano.swift.psu.edu/trigger_report?id=755839508/#:~:te… The probability skymap file can be downloaded from the link here [skymap_fits_file](https://guano.swift.psu.edu/files/755839508/0_n_PROBMAP) Instructions on how to read and manipulate this map can be found here: https://guano.swift.psu.edu/documentation More details about this burst can be found on the trigger report page here: https://guano.swift.psu.edu/trigger_report?id=755839508 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ View this GCN Circular online at https://gcn.nasa.gov/circulars/38582. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36580] Konus-Wind detection of GRB 241213A (EP 241213a)
by GCN Circulars 16 Dec '24

16 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38581 SUBJECT: Konus-Wind detection of GRB 241213A (EP 241213a) DATE: 24/12/16 15:00:39 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB 241213A (Swift-BAT detection: Gupta et al., GCN 38547; INTEGRAL-SPI-ACS detection: Barria et al., GCN 38556), associated with the fast X-ray transient EP241213a (Zhou et al., GCN 38554; Barria et al., GCN 38556), triggered Konus-Wind at T0=8344.058 s UT (02:19:04.058). The burst light curve shows a single pulse, which starts at ~T0-3.1 s and has a total duration of ~7.6 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB241213_T08344/ As observed by Konus-Wind, the burst had a fluence of 1.04(-0.07,+0.07)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.056 s, of 4.78(-1.05,+1.06)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.88(-0.17,+0.18) and Ep = 236(-24,+30) keV (chi2 = 74/77 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.6 (chi2 = 73/76 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/38581. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36579] GRB 241215A: Mondy AZT-33IK optical observations
by GCN Circulars 16 Dec '24

16 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38580 SUBJECT: GRB 241215A: Mondy AZT-33IK optical observations DATE: 24/12/16 12:34:55 GMT FROM: Nicolai Pankov at HSE, IKI RAS <colinsergesen(a)gmail.com> N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP) report on behalf of IKI-GRB-FuN: We performed optical observations of the field of GRB 241215A (Mereghetti et. al, GCN 38573; Mohan et. al, GCN 38574; Leonini et. al, GCN 38575; Liu et. al, GCN 38576) in the R filter with AZT-33IK of Sayan (Mondy) observatory. The observations began on 2024-12-15 14:27 UT, i.e. ~1.08 hr since INTEGRAL trigger. We have covered the entire localization area assessed by the INTEGRAL team (Mereghetti et. al, GCN 38573). No candidate transients were found using image subtraction with ```apex_subtract``` pipeline against the PS1 template image. The preliminary upper limit of the stacked image is given below: | Date | UTstart | t-T0 (mid, days) | Exptime (n*s) | Filter | Magnitude | UL (3sigma) | | ---------- | -------- | ---------------- | ------------- | ------ | --------- | ----------- | | 2024-12-15 | 14:27:52 | 0.044875 | 30*120 | R | n/d | 21.3 | The magnitudes were calibrated using nearby stars from USNO-B1.0 (R2 magnitudes) and are not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38580. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36578] GRB 241212A: Swift-XRT observations
by GCN Circulars 16 Dec '24

16 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38579 SUBJECT: GRB 241212A: Swift-XRT observations DATE: 24/12/16 06:42:41 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), D.N. Burrows (PSU), M. A. Williams (PSU), S. Dichiara (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected burst GRB 241212A, collecting 2.3 ks of Photon Counting (PC) mode data between T0+257.0 ks and T0+297.7 ks. No X-ray sources have been detected within the estimated 3-sigma SVOM/ECLAIRs error region (118 arcsec). The 3-sigma upper limit in the field is 0.004 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.4e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). An uncatalogued was detected, however this was too far from the GRB position to be the afterglow. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021740. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38579. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36577] GRB 241214A: SVOM/GRM observation
by GCN Circulars 16 Dec '24

16 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38578 SUBJECT: GRB 241214A: SVOM/GRM observation DATE: 24/12/16 04:28:43 GMT FROM: zhangjinpeng(a)ihep.ac.cn SVOM/GRM team: Jin-Peng Zhang, Chen-Wei Wang, Shi-Jie Zheng, Yong-Wei Dong, Jiang-Tao Liu, Jian-Chao Sun, Yue Huang, Jiang He, Min Gao, Hao-Xuan Guo, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming Song, You-Li Tuo, Wen-Long Zhang, Wen-Jun Tan, Yue Wang, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Ping Wang, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Lin Xiong, Jian-Ying Ye, Yi-Tao Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zhang, Shuang-Nan Zhang, Yan-Qiu Zhang, Yan-Ting Zhang, Shu-Min Zhao, Xiao-Yun Zhao, Chao Zheng (IHEP), Maria-Grazia Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Tais Maiolino (LUPM), Frédéric Piron (LUPM), Stéphane Schanne (CEA), Jingwei Wang (IAP), JeanLuc Attéia (IRAP) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) Report on behalf of the SVOM team: During the commissioning phase, the SVOM/GRM was triggered in-flight by GRB 241214A (SVOM trigger reference: sb24121401) at 2024-12-14T03:24:32.900 UT (T0). The real-time alert data and light curves of SVOM/GRM were downlinked to the ground through the VHF system with low latency. With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple pulses, with a T90 of 5.98 +2.07/-0.94 s. The GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb241214A.png The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Jin-Peng Zhang (IHEP)(zhangjinpeng(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/38578. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36576] The EP-WXT trigger 01709128948 is likely a flaring star
by GCN Circulars 16 Dec '24

16 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38577 SUBJECT: The EP-WXT trigger 01709128948 is likely a flaring star DATE: 24/12/16 02:51:52 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> M. Q. Huang, Z. Y. Liu (USTC), Q. C. Shui (IHEP, CAS), H. N. Yang, Y. Liu (NAO, CAS) report on behalf of the Einstein Probe team: The EP-WXT trigger (ID 01709128948) on 2024-12-15 20:23:50 (UTC) is likely a stellar flare associated with a young stellar object candidate ATO J079.4052-07.5576. The estimated flux of the flare is around (1.05 +- 0.02) x 10^-10 erg/s/cm^2 in 0.5-10.0 keV, corresponding to an X-ray luminosity of around (1.74 +- 0.03) x 10^33 erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with onboard X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/38577. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36575] GRB 241215A: Nanshan/HMT optical upper limit
by GCN Circulars 16 Dec '24

16 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38576 SUBJECT: GRB 241215A: Nanshan/HMT optical upper limit DATE: 24/12/16 01:31:20 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> X. Liu, S.Q. Jiang, J. An, S.Y. Fu, Z.P. Zhu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report on behalf of a large collaboration: We observed the field of GRB241215A detected by INTEGRAL/IBIS (Mereghetti et al., GCN 38573) using the HMT-0.5m telescope located at Nanshan, Xinjiang, China. Observations started at 2024-12-15T16:09:56.00, i.e., ~ 2.28 hrs after the INTEGRAL trigger and consisted of 15 x 90 s frames without any filter. No uncatalogued optical source is detected in our stacked images within the INTEGRAL/IBIS 2.5 arcmin error circle (Mereghetti et al., GCN 38573), down to a 3 sigma upper limit of r ~ 19.8, calibrated with nearby Pan-STARRS stars and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38576. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36574] GRB 241215A: Montarrenti Observatory optical upper limit
by GCN Circulars 15 Dec '24

15 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38575 SUBJECT: GRB 241215A: Montarrenti Observatory optical upper limit DATE: 24/12/15 23:46:31 GMT FROM: Simone Leonini at Montarrenti Observatory (Siena, Italy) <s.leonini(a)iol.it> S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy, part of UAI/SSV-GRB section), M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy) and K. Kalinowski (Aarhus University, Department of Physics and Astronomy) report: We performed follow-up observations of the field of GRB 241215A with the automated and remoted 0.53m Ritchey-Chretien telescope at Montarrenti Observatory (Siena, Italy, IAU code C88). Observations were started at 2024-12-15 17:34:42 UT, 3.83 hours after burst (Mereghetti et al., GCN 38573) stacking 80x40s Rc-band CCD images. In our preliminary analysis, we have not found any optical transient candidate within the error-box (2.5 arcmin.) of The INTEGRAL Burst Alert System position (RA 00h 42m 20.66s, Dec. +32d 31m 7.68s - J2000) down to the following 3-sigma optical upper limits: MJD Exp. Filter UL (3-sigma) 60660.2680 80x40s Rc > 20.3 Magnitude was calibrated with the nearby PanSTARRS stars converted using Lupton (2005) equations. No correction for galactic dust extinction was applied. The upper limit is consistent with other already reported (Lipunov et al., GCN 38572; Mohan et al., GCN 38574). View this GCN Circular online at https://gcn.nasa.gov/circulars/38575. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36573] GRB 241215A: GROWTH-India telescope optical upper limit
by GCN Circulars 15 Dec '24

15 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38574 SUBJECT: GRB 241215A: GROWTH-India telescope optical upper limit DATE: 24/12/15 19:47:09 GMT FROM: V. Swain at IIT Bombay <vishwajeet.s(a)iitb.ac.in> T. Mohan, A.P. Saikia, V. Swain, R. Kumar, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team: We observed the field of the GRB 241215A (Mereghetti et al., GCN 38573) with the 0.7m GROWTH-India Telescope (GIT). Observation started at 2024-12-15T15:27:41 UT, about 1.57 hours after the trigger. We responded to the coordinates reported in GCN notices (trigger No 11001, RA = 10.5810 deg, DEC = 32.4791 deg) and obtained multiple images of 300s in r' filter. With current FOV of 7.5 x 11 arcmin and scale: 0.2 arcsec/pixel, we covered 71 percent of the localization centered around refined coordinates given in GCN 38573. The obtained upper limit in our stacked image is: | MJD (mid) | Filter | Exposure (s) | Limiting Magnitude (AB) | | ----------- | ------ | ------------ | ----------------------- | | 60659.65319 | r' | 5x300 | 19.9 | | The upper limit is consistent with Lipunov et el., GCN 38572. The magnitude is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. The GROWTH India Telescope (GIT, Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/. View this GCN Circular online at https://gcn.nasa.gov/circulars/38574. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36572] GRB 241215A: A long GRB detected by INTEGRAL
by GCN Circulars 15 Dec '24

15 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38573 SUBJECT: GRB 241215A: A long GRB detected by INTEGRAL DATE: 24/12/15 15:02:10 GMT FROM: Sandro Mereghetti at IASF-Milano/INAF <sandro.mereghetti(a)inaf.it> S.Mereghetti (INAF, IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC, Versoix) and J.Borkowski (CAMK, Torun) report: a gamma ray burst lasting about 30 s has been detected by IBAS in the IBIS/ISGRI data at 13:53:15 UT of 2024 December 15. The refined coordinates (J2000) are: R.A.= 10.5861 deg DEC.= +32.5190 deg with an uncertainty of 2.5 arcmin (90% c.l.). The burst had a peak flux of 0.5 ph/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 4e-7 erg/cmq. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html View this GCN Circular online at https://gcn.nasa.gov/circulars/38573. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36571] Integral GRB241215.58: Global MASTER-Net observations report
by GCN Circulars 15 Dec '24

15 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38572 SUBJECT: Integral GRB241215.58: Global MASTER-Net observations report DATE: 24/12/15 14:19:47 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Integral GRB241215.58 (trigger No 11001,00h 42m 22.96s , +32d 29m 29.4s, R=0.0483333) errorbox 26 sec after notice time and 53 sec after trigger time at 2024-12-15 13:54:21 UT, with upper limit up to 17.5 mag. The observations began at zenith distance = 27 deg. The sun altitude is -44.6 deg. The galactic latitude b = -30 deg., longitude l = 121 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2710514 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 55 | MASTER-Tunka | C | 1 | 16.6 | 60 | MASTER-Tunka | C | 1 | 16.7 | 66 | MASTER-Tunka | C | 1 | 16.7 | 73 | MASTER-Tunka | C | 5 | 17.5 | 82 | MASTER-Tunka | C | 5 | 17.5 | 90 | MASTER-Tunka | C | 5 | 17.3 | 99 | MASTER-Tunka | C | 5 | 17.4 | 107 | MASTER-Tunka | C | 5 | 17.5 | 116 | MASTER-Tunka | C | 5 | 17.4 | 125 | MASTER-Tunka | C | 5 | 17.5 | 134 | MASTER-Tunka | C | 5 | 17.4 | 142 | MASTER-Tunka | C | 5 | 17.3 | 151 | MASTER-Tunka | C | 5 | 17.4 | 160 | MASTER-Tunka | C | 5 | 17.4 | 168 | MASTER-Tunka | C | 5 | 17.4 | 177 | MASTER-Tunka | C | 5 | 17.4 | 186 | MASTER-Tunka | C | 5 | 17.3 | 195 | MASTER-Tunka | C | 5 | 17.4 | 204 | MASTER-Tunka | C | 5 | 17.4 | 212 | MASTER-Tunka | C | 5 | 17.3 | 221 | MASTER-Tunka | C | 5 | 17.4 | 230 | MASTER-Tunka | C | 5 | 17.5 | 238 | MASTER-Tunka | C | 5 | 17.4 | 247 | MASTER-Tunka | C | 5 | 17.4 | 255 | MASTER-Tunka | C | 5 | 17.4 | 264 | MASTER-Tunka | C | 5 | 17.5 | 272 | MASTER-Tunka | C | 5 | 17.5 | 281 | MASTER-Tunka | C | 5 | 17.5 | 290 | MASTER-Tunka | C | 5 | 17.4 | 298 | MASTER-Tunka | C | 5 | 17.3 | 307 | MASTER-Tunka | C | 5 | 17.4 | 316 | MASTER-Tunka | C | 5 | 17.4 | 324 | MASTER-Tunka | C | 5 | 17.4 | 341 | MASTER-Tunka | C | 5 | 17.4 | 350 | MASTER-Tunka | C | 5 | 17.4 | 359 | MASTER-Tunka | C | 5 | 17.4 | 368 | MASTER-Tunka | C | 5 | 17.5 | 376 | MASTER-Tunka | C | 5 | 17.4 | 385 | MASTER-Tunka | C | 5 | 17.4 | 393 | MASTER-Tunka | C | 5 | 17.4 | 402 | MASTER-Tunka | C | 5 | 17.5 | 410 | MASTER-Tunka | C | 5 | 17.5 | 426 | MASTER-Tunka | C | 5 | 17.5 | 437 | MASTER-Tunka | C | 5 | 17.5 | 445 | MASTER-Tunka | C | 5 | 17.4 | 454 | MASTER-Tunka | C | 5 | 17.4 | 463 | MASTER-Tunka | C | 5 | 17.5 | 471 | MASTER-Tunka | C | 5 | 17.4 | 482 | MASTER-Tunka | C | 5 | 17.5 | 491 | MASTER-Tunka | C | 5 | 17.5 | 500 | MASTER-Tunka | C | 5 | 17.5 | 509 | MASTER-Tunka | C | 5 | 17.4 | 518 | MASTER-Tunka | C | 5 | 17.4 | 526 | MASTER-Tunka | C | 5 | 17.4 | 535 | MASTER-Tunka | C | 5 | 17.4 | 543 | MASTER-Tunka | C | 5 | 17.3 | 552 | MASTER-Tunka | C | 5 | 17.4 | 571 | MASTER-Tunka | C | 5 | 17.3 | 583 | MASTER-Tunka | C | 5 | 17.3 | 593 | MASTER-Tunka | C | 5 | 17.4 | 602 | MASTER-Tunka | C | 5 | 17.4 | 611 | MASTER-Tunka | C | 5 | 17.4 | 620 | MASTER-Tunka | C | 5 | 17.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38572. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36570] The EP-WXT trigger 01709128921 is likely a flaring star
by GCN Circulars 15 Dec '24

15 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38571 SUBJECT: The EP-WXT trigger 01709128921 is likely a flaring star DATE: 24/12/15 10:01:09 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> A. Li (BNU), M. Q. Huang, Z. Y. Liu (USTC), W. J. Zhang, Y. Liu (NAO,CAS) report on behalf of the Einstein Probe team: The EP-WXT trigger (ID 01709128921) on 2024-12-15 08:43:05.749 (UTC) is likely a stellar flare associated with a double or multiple star RX J0413.4-0139. The estimated flux of the flare is around 2.0 x 10^-10 erg/s/cm^2 in 0.5-4 keV, corresponding to an X-ray luminosity of around 1.7 x 10^31 erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with onboard X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/38571. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36569] GRB 241213B: Swift-XRT observations
by GCN Circulars 14 Dec '24

14 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38570 SUBJECT: GRB 241213B: Swift-XRT observations DATE: 24/12/14 17:30:10 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> A.P. Beardmore (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), J.A. Kennea (PSU), D.N. Burrows (PSU), M. A. Williams (PSU), J.P. Osborne (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 241213B in a series of observations tiled on the sky. The total exposure time is 2.2 ks, distributed over 7 tiles; the maximum exposure at a single sky location in the tiling was 822 s. The data were collected between T0+54.1 ks and T0+60.2 ks, and are entirely in Photon Counting (PC) mode. One uncatalogued X-ray source has been detected, it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below: Source 1: RA (J2000.0): 331.7177 = 22:06:52.25 Dec (J2000.0): +4.0971 = +04:05:49.6 Error: 9.0 arcsec (radius, 90% conf.) Count-rate: 0.0185 [+0.0089, -0.0068] ct s^-1 Distance: 1169 arcsec from MAXI position. Flux: (1.21 [+0.59, -0.44])e-9 erg cm^-2 s^-1 (observed, 0.3-10 keV) The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00130. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38570. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36568] GRB 241209D: CALET Gamma-Ray Burst Monitor detection
by GCN Circulars 14 Dec '24

14 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38569 SUBJECT: GRB 241209D: CALET Gamma-Ray Burst Monitor detection DATE: 24/12/14 09:21:25 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo(a)phys.aoyama.ac.jp> A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The long GRB 241209D (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ 38488; Swift detection of a burst: Parsotan et al., GCN Circ 38489; Fermi GBM Observation: Malacaria et al., GCN Circ 38507; AstroSat CZTI detection: Tembhurnikar et al., GCN Circ 38518; Konus-Wind detection: Ridnaia et al., GCN Circ 38526) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 10:59:46.760 UTC on 9 December 2024 (https://cgbm.calet.jp/cgbm_trigger/flight/1417777157/index.html). The burst signal was seen by only the SGM detector. Because of a problem with the ground alert processing script, the GCN notice was not distributed automatically for this event. The burst light curve shows a single pulse that starts at T-4.0 sec, peaks at T+0.6 sec, and ends at T+6.7 sec. The T90 and T50 durations measured by the SGM data are 9.2 +/- 0.7 sec and 4.6 +/- 0.4 sec (40-1000 keV), respectively. The ground-processed light curve is available at https://cgbm.calet.jp/cgbm_trigger/ground/1417777157/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at Waseda University. View this GCN Circular online at https://gcn.nasa.gov/circulars/38569. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36567] GRB 241209B: SVOM/VT optical continuous fading
by GCN Circulars 14 Dec '24

14 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38568 SUBJECT: GRB 241209B: SVOM/VT optical continuous fading DATE: 24/12/14 06:11:47 GMT FROM: Chao Wu at NAOC <cwu(a)nao.cas.cn> SVOM/VT commissioning team: Y. L. Qiu, H. L. Li, L. P. Xin, C. Wu, X. H. Han, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. Deng, L. Lan, X. M. Lu, R. S. Zhang, D. H. Zhao (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM), H. Zhou (PMO), C. Plasse (CEA) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) report on behalf of the SVOM team: SVOM/VT revisited GRB 241209B（Xie et al., GCN 38478）since 2024-12-10T15:07:15 UT with a total exposure time of 8750 seconds. The optical counterpart (Qiu et al. GCN 38516) was continuously fading, reaching a magnitude of 23.70 +/-0.30 in VT_R. Nothing was seen down to limiting magnitude of 23.80 (3 sigma) in simultaneous channel VT_B. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC),CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/38568. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36566] EP trigger ID 01709128824 is not a real source
by GCN Circulars 14 Dec '24

14 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38567 SUBJECT: EP trigger ID 01709128824 is not a real source DATE: 24/12/14 06:00:09 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> D.-F. Hu (PMO, CAS), X.-Y. Zhou (PRIC), R.-Z. Li (YNAO, CAS), S.-X. Wen, H.-W. Pan (NAO, CAS) report on behalf of the Einstein Probe team: WXT trigger ID: 01709128824 is not a real source. It is a trigger caused by the arm of the point spread function of a bright known source on the detector image. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/38567. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36565] GRB 241213A: SVOM/VT optical candidate
by GCN Circulars 14 Dec '24

14 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38566 SUBJECT: GRB 241213A: SVOM/VT optical candidate DATE: 24/12/14 04:24:28 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> SVOM/VT commissioning team: Y. L. Qiu, H. L. Li (NAOC), Y. Wang (PMO), R.-Z. Li (YNAO), L. P. Xin, C. Wu, X. H. Han, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. Deng, L. Lan, X. M. Lu, R. S. Zhang, D. H. Zhao (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) report on behalf of the SVOM team: The SVOM/VT conducted follow-up observations of the Swift-triggered GRB 241213A (Gupta et al., GCN 38547) in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously, from 10.636 hours to 15.7 hours after the burst. With the X band downlinked data, an uncatalogued optical source was detected within the errorbox of XRT (Osborne et al., GCN 38552) in VT_R stacked image, compared to the PanSTARRS catalog. The brightness of the source was estimated to be 23.8 ± 0.3 mag in AB magnitude in VT_R image at the mid time of 13.6 hours post the burst, with a total exposure time of 135*50 seconds. The source can not be detected in VT_B stacked image with 3 sigma upper limit of ~24.0 mag in AB magnitude. The source is located at RA, Dec = 116.17031, 35.27805, which is equivalent to: RA (J2000) : 07:44:40.87 Dec (J2000): +35:16:40.99 with an uncertainty of 0.5 arcsec. We proposed that this source is the candidate for the gamma-ray burst. Further follow-ups with SVOM/VT are scheduled to confirm the nature of the source. More deep follow-ups are encouraged. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/38566. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36564] GRB 241213B: Tiled Swift observations
by GCN Circulars 14 Dec '24

14 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38565 SUBJECT: GRB 241213B: Tiled Swift observations DATE: 24/12/14 03:58:22 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the MAXI GRB 241213B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00130 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the MAXI event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38565. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36563] GRB 241213A: Swift/UVOT Upper Limits
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38564 SUBJECT: GRB 241213A: Swift/UVOT Upper Limits DATE: 24/12/13 22:54:19 GMT FROM: Sam Shilling at Lancaster University <shilling.sam(a)gmail.com> S.P.R. Shilling (Lancaster) and R. Gupta (NASA GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 241213A 106 s after the BAT trigger (Gupta et al., GCN Circ. 38547). No optical afterglow consistent with the enhanced XRT position (Osborne et al., GCN Circ. 38552) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 106 256 147 >20.6 u_FC 318 568 246 >19.8 white 106 945 259 >20.7 v 648 4786 236 >19.2 b 573 766 39 >19.0 u 318 742 265 >19.9 w1 698 5045 67 >18.7 m2 673 4991 216 >19.5 w2 624 4581 236 >19.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.060 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/38564. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36562] GRB 241213B: CALET Gamma-Ray Burst Monitor detection
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38563 SUBJECT: GRB 241213B: CALET Gamma-Ray Burst Monitor detection DATE: 24/12/13 16:50:42 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo(a)phys.aoyama.ac.jp> P. S. Marrocchesi (U of Siena), A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), and the CALET collaboration: The GRB 241213B (MAXI/GSC detection: Negoro et al., GCN Circ. 38555) was detected in the ground analysis of the CALET Gamma-ray Burst Monitor (CGBM) data around 12:56:30 on 13 December 2024 (referenced to the MAXI detection: GCN Circ. 38555). (https://cgbm.calet.jp/cgbm_trigger/flight/1418129753/index.html). The burst signal was seen by all CGBM detectors. The burst light curve shows a single pulse that starts at T+1.8 sec, peaks at T+2.4 sec, and ends at T+4.5 sec. The T90 and T50 durations measured by the SGM data are 2.4 +/- 0.5 sec and 1.2 +/- 0.4 sec (7-100 keV), respectively. The ground-processed light curve is available at https://cgbm.calet.jp/cgbm_trigger/ground/1418129753/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at Waseda University. View this GCN Circular online at https://gcn.nasa.gov/circulars/38563. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36561] GRB 241213A: Swift-XRT refined Analysis
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38562 SUBJECT: GRB 241213A: Swift-XRT refined Analysis DATE: 24/12/13 16:21:52 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: We have analysed 4.5 ks of XRT data for GRB 241213A, from 106 s to 33.0 ks after the BAT trigger. The data comprise 275 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The light curve can be modelled with an initial power-law decay with an index of alpha=0.59 (+0.07, -0.08), followed by a break at T+680 s to an alpha of 1.20 (+0.16, -0.06). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.89 (+/-0.10). The best-fitting absorption column is 3.3 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 6.7 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.85 (+/-0.14) and a best-fitting absorption column of 3.9 (+0.8, -0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.3 x 10^-11 (6.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.9 (+0.8, -0.7) x 10^21 cm^-2 Galactic foreground: 6.7 x 10^20 cm^-2 Excess significance: 7.4 sigma Photon index: 1.85 (+/-0.14) If the light curve continues to decay with a power-law decay index of 1.20, the count rate at T+24 hours will be 0.014 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.9 x 10^-13 (8.5 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01274039. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38562. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36560] GRB 241212A: Fermi GBM detection
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38561 SUBJECT: GRB 241212A: Fermi GBM detection DATE: 24/12/13 15:43:11 GMT FROM: Joe Mangan at IJCLab <joseph.mangan(a)ijclab.in2p3.fr> J. Mangan (CNRS/IJCLab) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 09:21:48.66 UT on 12 December 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241212A (trigger 755688113 / 241212390), which was also detected by, SVOM-GRM (Zhang Li et al. 2024, GCN 38541), and for which there is a possible optical counterpart (P.A. Evans et al. 2024, GCN 38559). The Fermi GBM Final Real-time Localization is reported in GCN 38540. The angle from the Fermi LAT boresight at the GBM trigger time is 40 degrees. The GBM light curve consists of a single emission with a duration (T90) of about 39 s (50-300 keV). The time-averaged spectrum from T0-0 s to T0+34 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.1 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 304.8 +/- 59.1 keV. The event fluence (10-1000 keV) in this time interval is (5.8 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+4.4 s in the 10-1000 keV band is 2.8 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/38561. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36559] EP241208a: NOT optical upper limits
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38560 SUBJECT: EP241208a: NOT optical upper limits DATE: 24/12/13 15:33:41 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> X. Liu, J. An, S.Q. Jiang, S.Y. Fu, Z.P. Zhu, D. Xu (NAOC), J.P.U. Fynbo (DAWN/NBI), A.H. de la Fuente, A.G. Theil (NOT) report: We observed the field of EP241208a detected by EP-WXT (Wang et al., GCN 38477) and SVOM/ECLAIRs (Atteia et al., GCN 38557) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations started at 02:48:15.84 UT on 2024-12-09, i.e., ~ 10.20 hrs after the EP-WXT trigger, and 5 x 200 s Sloan r- and z- band images were obtained, respectively. No new optical source is found within the ~ 10 arcsec EP-FXT error circle (Wang et al., GCN 38513) after performing image differencing using the DESI Legacy Survey as template, down to the following 3-sigma limits: Filter Tmid-T0 (hr) UL (AB) ------------------------------------------- r 10.35 >23.2 z 10.67 >21.7 calibrated with nearby Pan-STARRS stars and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38560. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36558] GRB 241212A: Swift ToO observations
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38559 SUBJECT: GRB 241212A: Swift ToO observations DATE: 24/12/13 15:26:28 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the SVOM/ECLAIRs GRB 241212A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021740 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the SVOM/ECLAIRs event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38559. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36557] GRB 241213A: LCOGT Optical Upper Limits
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38558 SUBJECT: GRB 241213A: LCOGT Optical Upper Limits DATE: 24/12/13 14:28:54 GMT FROM: Robert Strausbaugh at Eastern Illinois University <rstrausbaugh(a)eiu.edu> R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the Swift GRB 241213A field (Gupta et al., GCN 38547) with the LCOGT 1-meter Sinistro instrument at the McDonald Observatory USA site, on December 13, from 06:49 to 07:19 UT (corresponding to 4.50 to 5.00 hours after the GRB trigger time) with the sdss r and i filters. We performed a series of 3x300s exposures in i-band and 2x300s in r-band. We do not detect a source within the Swift XRT enhanced error region (Osborne et al., GCN 38552) in either band, consistent with other optical upper limits (Lipunov et al., GCN 38548; Spiridonova et al., GCN 38550; Brivio et al., GCN 38553). The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference: r > 21.2 i > 21.5 These magnitudes are not corrected for galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38558. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36556] EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38557 SUBJECT: EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs DATE: 24/12/13 14:10:43 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> SVOM/ECLAIRs Commissioning Team: Jean-Luc Atteia, Laurent Bouchet, Marius Brunet, Sebastien Guillot, Juliette Alaux, Hui Yang (IRAP), Stéphane Schanne, Damien Turpin, Nicolas Dagoneau, Frédéric Chateau, Hervé Le Provost (CEA), Wenjin Xie, Donghua Zhao (NAOC), Floriane Cangemi (APC), Tais Maiolino (LUPM), Karine Mercier, Marie-Claire Charmeau, Stefano Crepaldi (CNES) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Olivier Godet (IRAP), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (UNLV) report on behalf of the SVOM team: During the commissioning phase, the SVOM/ECLAIRs telescope detected and localized the long soft transient EP241208A, also detected by Einstein Probe (GCN circular [https://gcn.nasa.gov/circulars/38477](38477)) at 2024-12-08T16:35:50.016 UTC (Tb) through an offline search with the event-by-event data downloaded through the X-band ground station. The burst was detected by several methods and within several energy ranges and timescales. The best detection is obtained by the image trigger with a signal-to-noise ratio of 6.1 within 4-8 keV over a time window of 10.24 seconds starting at Tb. The lightcurve shows a single peak of duration of about 10s. No emission has been detected above 20 keV. The localization of the best Alert is RA, Dec = 127.785, 48.861 (J2000) which is consistent with EP one.The statistical uncertainty on this position is 13 arcminutes, to which we recommend adding 2 arcminutes of systematic uncertainty in quadrature. Spectral analysis is ongoing and will be published in a future circular. ECLAIRs did not detect this burst onboard because its significance was below the onboard trigger Alert threshold. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. ECLAIRs was developed jointly by APC, CEA, CNES, and IRAP. The SVOM point of contact for this burst is: Marius Brunet (IRAP) marius.brunet(a)irap.omp.eu View this GCN Circular online at https://gcn.nasa.gov/circulars/38557. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36555] EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38556 SUBJECT: EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart DATE: 24/12/13 13:46:38 GMT FROM: Aishwarya L Thakur at INAF-IAPS, Rome <aishth(a)outlook.com> Patrizia Barria(a,b), Giulia Gianfagna(a), James Craig Rodi(a), Aishwarya Linesh Thakur(a), Luigi Piro(a), Lorenzo Natalucci(a,b) report: The fast X-ray transient, EP241213a, was discovered by the Einstein Probe/WXT (GCN 38554). This transient appears to be spatially coincident with GRB 241213A (BAT: GCN 38547, XRT: GCN 38552), as the XRT coordinates are consistent with the 2.8 arcmin WXT error circle. There is a temporal delay of ~ 100 s between the BAT and WXT detections. We searched for any corresponding emission in the INTEGRAL/SPI-ACS data. In a light curve above 80 keV, we find a pulse temporally coincident with the BAT detection (thus occurring ~ 100 s after the EP/WXT detection, assuming they are the same event), with an approximate duration of 10 sec. The approximate peak count rate is 80000 cts/s over a median background rate of 62500 cts/s. This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany. ----- (a) INAF/IAPS-Rome (b) ICSC National Research Centre for High-Performance Computing View this GCN Circular online at https://gcn.nasa.gov/circulars/38556. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36554] GRB 241213B: MAXI/GSC detection
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38555 SUBJECT: GRB 241213B: MAXI/GSC detection DATE: 24/12/13 13:30:39 GMT FROM: Hitoshi Negoro at Nihon University/MAXI team <negoro.hitoshi(a)nihon-u.ac.jp> H. Negoro (Nihon U.), M. Serino, Y. Kawakubo (AGU), W. Iwakiri (Chiba U.), M. Nakajima, Y. Kudo, H. Shibui, K. Takagi, H. Takahashi, K. Tatano, H. Nishio (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, S. Wang, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, Y. Kondo, S. Sasao, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.), M. Shidatsu, Y. Niida (Ehime U.), I. Takahashi, M. Niwano, N. Higuchi, Y. Yatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA), Y. Ueda, Y. Okada, K. Fujiwara (Kyoto U.), M. Yamauchi, Y. Otsuki, T. Hasegawa, M. Nishio (Miyazaki U.), K. Yamaoka (Nagoya U.), and M. Sugizaki (Kanazawa U.) The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient source at 12:56:30 UT on 2024 December 13. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (331.450 deg, 4.282 deg) = (22 05 48, +04 16 55) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.16 deg and 0.15 deg, respectively. The roll angle of the long axis from the north direction is 141.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 465 +- 58 mCrab (4.0-10.0keV, 1 sigma error). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners: (R.A., Dec) = (331.162, 4.788) deg = (22 04 38, +04 47 16) (J2000) (R.A., Dec) = (330.936, 4.585) deg = (22 03 44, +04 35 05) (J2000) (R.A., Dec) = (331.900, 3.518) deg = (22 07 35, +03 31 04) (J2000) (R.A., Dec) = (332.126, 3.721) deg = (22 08 30, +03 43 15) (J2000) There was no significant excess flux in the previous transit at 11:23 UT with an upper limit of 20 mCrab. View this GCN Circular online at https://gcn.nasa.gov/circulars/38555. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36553] EP241213a: EP detection of An X-ray Transient
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38554 SUBJECT: EP241213a: EP detection of An X-ray Transient DATE: 24/12/13 12:12:13 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> X.-Y. Zhou (PRIC), R.-Z. Li (YNAO, CAS), D.-F. Hu (PMO, CAS), S.-X. Wen, H.-W. Pan (NAO, CAS) report on behalf of the Einstein Probe team: We report on the detection of an X-ray transient by the Einstein Probe (EP), designated as EP241213a. The source was first detected by the Wide-field X-ray Telescope (WXT) on board EP in a single pointing observation (with an exposure time of 1.6 ks) at 2024-12-13T02:17:15 (UTC). The position of the transient is R.A. = 116.182 deg, Dec. = 35.271 deg, with an uncertainty of 2.8 arcmin. No previously known bright X-ray sources are found within the error circle around the transient position. The WXT spectrum of the observation can be fitted by an absorbed power law with a photon index of 2.2+/-1.4, with the NH of (5.9+/-4.8) e21 cm^-2. The derived absorbed flux in 0.5-4 keV is ~5.2e-11 ergs/s/cm^2. A Swift-XRT ToO proposal was submitted to observe the transient. Multi-wavelength follow-up observaitons are encouraged. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/38554. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36552] GRB 241213A: REM optical/NIR upper limits
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38553 SUBJECT: GRB 241213A: REM optical/NIR upper limits DATE: 24/12/13 12:02:01 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R.Brivio, M. Ferro, P. D’Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 241213A detected by Swift/BAT (Gupta et al., GCN 38547) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2024 December 13 at 03:50:29 UT (i.e. 1.5 hours after the Swift trigger), and lasting for about 1 hour. From preliminary photometry we do not detect any counterpart in the optical and NIR images at the enhanced Swift-XRT position (Osborne et al., GCN 38552) down to the following 3sigma magnitude upper limits: r > 19.5 (AB; calibrated against the PanSTARRS catalogue) at a mid-time of t - t0 = 2.1 hr after the trigger, J > 17.8 (Vega; calibrated against the 2MASS catalogue) at a mid-time of t - t0 = 2.2 hr after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/38553. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36551] GRB 241213A: Enhanced Swift-XRT position
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38552 SUBJECT: GRB 241213A: Enhanced Swift-XRT position DATE: 24/12/13 11:28:36 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 433 s of XRT Photon Counting mode data and 1 UVOT images for GRB 241213A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 116.16998, +35.27882 which is equivalent to: RA (J2000): 07h 44m 40.80s Dec (J2000): +35d 16' 43.8" with an uncertainty of 3.4 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38552. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36550] GRB241212A: OHP/T193 optical observations
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38551 SUBJECT: GRB241212A: OHP/T193 optical observations DATE: 24/12/13 10:32:53 GMT FROM: Christophe Adami at LAM <christophe.adami(a)lam.fr> C. Adami (LAM/Pytheas/AMU), J. Schmitt (OHP/Pytheas/AMU), S. Basa (LAM/OHP/Pytheas/AMU) report on behalf of a larger collaboration: We observed the field of GRB241212A (Fermi GBM team, GCN 38540; Zhang Li et al., GCN 38541; Joshi et al., GCN 38544; Qiu et al., GCN 38545; Zhe Kang et al., GCN 38546) using the T193cm telescope at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. Six exposures were obtained in the Y-band (6x300s) with the MISTRAL red mode during technical time from 2024 12 December 18:43 UT to 2024 12 December 19:15 UT (~+9.5h after detection). The moon was at an illumination of ~92% and at a distance of 13deg from target. We do not detect the SVOM VT GRB counterpart provided by Qiu et al. (GCN 38545). The combined frame has a detection upper limit of Y~19.25+/-0.6 (5sigma limit). The photometric calibration was performed using objects from the PanSTARRS catalog. The magnitude is not corrected for Galactic extinction. We acknowledge the excellent support from Observatoire de Haute-Provence, in particular Jean Pierre Troncin and the SOPHIE observers Guillaume Hebrard and Florian Destriez. View this GCN Circular online at https://gcn.nasa.gov/circulars/38551. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36549] GRB 241213A: SAO RAS optical upper limit
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38550 SUBJECT: GRB 241213A: SAO RAS optical upper limit DATE: 24/12/13 09:16:58 GMT FROM: Moskvitin Alexander at SAO RAS <mosk(a)sao.ru> O. I. Spiridonova and A. S. Moskvitin (SAO RAS), report on behalf of the GRB follow-up team. We observed the field of GRB 241213A (Gupta et al. GCN Circ. 38547) with the 1-m telescope of SAO RAS, Zeiss-1000 + CCD-photometer on December 12, 02:30:40--02:52:17 UT (t_mid - T0 = 1349 sec.), observations started 700 seconds after the trigger. We obtained 4 x 300 sec images in Rc band under poor seeing and weather conditions. Inside the XRT error circle we did not detect any significant object (as well as Lipunov et al., GCN Circ. 38548) down to the limiting magnitude of R_lim = 21.0, calibrated against nearby PS1 stars (magnitudes were converted with the Lupton 2005 equations and not corrected for the MW extinction). View this GCN Circular online at https://gcn.nasa.gov/circulars/38550. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36548] LIGO/Virgo/KAGRA S241210fu: Updated Sky localization
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38549 SUBJECT: LIGO/Virgo/KAGRA S241210fu: Updated Sky localization DATE: 24/12/13 08:58:43 GMT FROM: Marie Anne Bizouard at ARTEMIS/CNRS <marieanne.bizouard(a)oca.eu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S241210fu (GCN Circular 38521). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S241210fu For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 3326 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3603 +/- 1378 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 View this GCN Circular online at https://gcn.nasa.gov/circulars/38549. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36547] Swift GRB 241213A: Global MASTER-Net observations report
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38548 SUBJECT: Swift GRB 241213A: Global MASTER-Net observations report DATE: 24/12/13 02:56:33 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 241213A ( R. Gupta et al., GCN 38547) errorbox 1183 sec after notice time and 1208 sec after trigger time at 2024-12-13 02:39:08 UT, with upper limit up to 17.8 mag. The observations began at zenith distance = 38 deg. The sun altitude is -20.1 deg. The galactic latitude b = 26 deg., longitude l = 185 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2708197 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 1289 | MASTER-Kislovodsk | P- | 160 | 17.6 | 1469 | MASTER-Kislovodsk | P- | 520 | 17.8 | Coadd 1467 | MASTER-Kislovodsk | P- | 180 | 16.9 | 1667 | MASTER-Kislovodsk | P- | 180 | 16.4 | The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38548. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36546] GRB 241213A: Swift detection of a burst
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38547 SUBJECT: GRB 241213A: Swift detection of a burst DATE: 24/12/13 02:39:47 GMT FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk> R. Gupta (NASA GSFC), C. Gronwall (PSU), K. L. Page (U Leicester) and T. Sakamoto (AGU) report on behalf of the Neil Gehrels Swift Observatory Team: At 02:19:00 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 241213A (trigger=1274039). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 116.148, +35.280 which is RA(J2000) = 07h 44m 35s Dec(J2000) = +35d 16' 49" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a bright peak with a duration of about 15 sec. The peak count rate was ~9500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 02:25:36.0 UT, 395.9 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 116.17145, 35.27944 which is equivalent to: RA(J2000) = 07h 44m 41.15s Dec(J2000) = +35d 16' 46.0" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 68 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (6.66 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 5 (+2.07/-1.84) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 250 seconds with the U filter starting 318 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.060. Burst Advocate for this burst is R. Gupta (rahulbhu.c157 AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/38547. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36545] GRB 241212A : SVOM/C-GFT optical upper limit at early phase
by GCN Circulars 13 Dec '24

13 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38546 SUBJECT: GRB 241212A : SVOM/C-GFT optical upper limit at early phase DATE: 24/12/13 00:58:36 GMT FROM: Chao Wu at NAOC <cwu(a)nao.cas.cn> SVOM/C-GFT team: Zhe Kang (CHO), Chao WU (NAOC), Liping Xin(NAOC), Xuhui Han(NAOC), Pinpin Zhang (NAOC), Xiaomeng Lu (NAOC), Zhenwei Li (CHO), You Lv (CHO), Ruosong Zhang (NAOC), Yujie Xiao(NAOC) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC),Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) We observed the field of GRB 241212A (Zhang et. al, GCN 38541; Fermi team GCN 38540;Joshi et al. GCN 38544) starting at 2024-12-12T09:22:45 UT, ~53 sec after the burst trigger with C-GFT. A series of g, r and i band images were obtained with exposure time of 10s. Due to bad observation condition(not good weather, low altitude and ~13.8 deg to the moon), the optical counterpart reported by Qiu et al. (GCN 38545) was not detected in the images. The upper limit at early phase are, (T-T0)_mid(sec) limiting_mag(3sigma) ------------------------------------- 58 15.80 91 16.80 The photometry was calibrated with nearby stars in ucac4. We thank the observation assistant Bowen Li and Chunlei Guo at Jilin observatory for their excellent support. Chinese Ground Follow-up Telescope of SVOM mission is located at Jilin, Changchun Observatory, National Astronomical Observatories, CAS. It has FOV of 1.28 deg x 1.28 deg with a 4k*4k CMOS detector mounted on the primary focus of 1.2-meter-aperure telescope. View this GCN Circular online at https://gcn.nasa.gov/circulars/38546. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36544] GRB 241212A : SVOM/VT bright optical afterglow
by GCN Circulars 12 Dec '24

12 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38545 SUBJECT: GRB 241212A : SVOM/VT bright optical afterglow DATE: 24/12/12 20:40:17 GMT FROM: Liping Xin at NAOC, SVOM <xlp(a)nao.cas.cn> SVOM/VT commissioning team: Y. L. Qiu, H. L. Li, L. P. Xin, C. Wu, X. H. Han, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. Deng, L. Lan, X. M. Lu, R. S. Zhang, J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM), H. Zhou (PMO), Li Zhang (IHEP) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) report on behalf of the SVOM team: The GRB 241212A (Zhang et al., GCN 38541; Fermi GBM team et al., GCN 38540) was observed by on-board SVOM/VT after the automatic slew of the platform. The VT conducted observations in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously. With the X band downlinked data, an uncatalogued optical source was detected in VT_B and VT_R band images within the errorbox in both Eclairs and MXT (Zhang et al., GCN 38541) compared to the Desi D10 catalog. The source is located at RA, Dec = 45.08033, 6.71682, which is equivalent to: RA (J2000) : 03:00:19.28 Dec (J2000): +06:43:00.56 with an uncertainty of 0.2 arcsec. Its brightness was fading for 1.1 magnitude in both of VT_B and VT_R images from 0.7 hours to 4.8 hours after the burst. The magnitude was VT_B = 20.60 mag and VT_R = 19.88 mag in AB magnitude,about 1.15 hr post the trigger. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC),CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/38545. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36543] GRB 241212A: AstroSat CZTI detection
by GCN Circulars 12 Dec '24

12 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38544 SUBJECT: GRB 241212A: AstroSat CZTI detection DATE: 24/12/12 15:45:53 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in> J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 241212A which was also detected by Fermi/GBM (Fermi-GBM Team, GCN Circ. 38540), and SVOM/ECLAIRs (Li et al., GCN Circ. 38541). The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-12-12 09:21:49.4 UTC. The measured peak count rate associated with the burst is 238 (+71, -38) counts/s above the background in the combined data of all quadrants, with a total of 1473 (+319, -369) counts. The local mean background count rate was 1331 (+6, -7) counts/s. We measure a T90 of 14 (+1, -6) s from the cumulative Veto light curve. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grbs View this GCN Circular online at https://gcn.nasa.gov/circulars/38544. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36542] GRB 241209B: GRANDMA/TRT upper limit
by GCN Circulars 12 Dec '24

12 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38543 SUBJECT: GRB 241209B: GRANDMA/TRT upper limit DATE: 24/12/12 15:00:34 GMT FROM: marion.pillas(a)ligo.org M. Pillas (ULiege), M. Tanasan, K. Noysena (NARIT), S. Antier (OCA), O. Pyshna (Caltech), N. Guessoum (AUS), A. Klotz (IRAP), C. Andrade (UMN) S. Karpov (FZU), M. Coughlin (UMN), , P. Hello (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/IPHC), D.Turpin (CEA-Saclay/Irfu), on behalf of the GRANDMA collaboration: We observed the field of GRB 241209B, detected by SVOM/ECLAIRs and GRM (GCN 38478) using TRT-SRO. Observations began 0.209 days after ECLAIRs T0. We didn't detect any optical afterglow candidate with an upper limit of 22 mag in Johnson-R (3 sigma, Vega Mag) Further analysis is required to check consistency with the afterglow candidate of SVOM/VT (GCN 38516). All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/). View this GCN Circular online at https://gcn.nasa.gov/circulars/38543. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36541] GRB 241207A: TSHAO Zeiss-1000 optical observations
by GCN Circulars 12 Dec '24

12 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38542 SUBJECT: GRB 241207A: TSHAO Zeiss-1000 optical observations DATE: 24/12/12 14:19:10 GMT FROM: Nicolai Pankov at HSE, IKI RAS <colinsergesen(a)gmail.com> N. Pankov (HSE, IKI), I. Reva (FAI), M. Krugov (FAI), A. Pozanenko (IKI) report on behalf of IKI-GRB-FuN: We performed optical observations of GRB 241207A (Fermi GBM team, GCN 38454; V.Lipunov et. al, GCN 38459; McKenna et. al, GCN 38536) in the R filter with 1-meter Zeiss-1000 telescope of Tien-Shan observatory (TSHAO). The observations began on 2024-12-07 13:04:43 UT, i.e. ~0.17 days since trigger. Using STDWeb (Karpov, 2024) ZOGY-based image subtraction against ZTF DR7 we did not find an optical candidate transient in the median stacked images of the fields: FieldID RA Dec Width Height (hr) (deg) (arcmin) 1 19:15:05 +42:01:05 19.03 19.03 2 19:09:58 +42:29:55 19.03 19.03 The preliminary upper limits are as follows: Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) FieldID (mid, days) (s) 2024-12-07 13:04:43 0.176087 4*90 R n/d n/d 20.3 1 2024-12-07 13:15:56 0.206782 48*90 R n/d n/d 20.8 2 The magnitudes were calibrated using nearby stars from USNO-B1.0 (R2 magnitudes) and are not corrected for the Galactic extinction towards the GRB 241207A. View this GCN Circular online at https://gcn.nasa.gov/circulars/38542. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36540] GRB 241212A: SVOM detection of a bright long burst
by GCN Circulars 12 Dec '24

12 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38541 SUBJECT: GRB 241212A: SVOM detection of a bright long burst DATE: 24/12/12 10:40:13 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Zhang Li (IHEP), Wenjin Xie (NAOC), Nicolas Dagoneau, Stéphane Schanne (CEA), Maria-Grazia Bernardini (INAF, LUPM), Clara Plasse (CEA), Shaolin Xiong (IHEP) report: At 2024-12-12T09:21:49 (Tb) SVOM/ECLAIRs triggered on GRB 241212A (SVOM burst-id sb24121201), also detected by Fermi GBM (GCN Circular 38540). The following trigger information was received on the ground with low-latency by the SVOM VHF Alert Network. A total of 12 Alerts were received from Count-Rate Trigger (CRT) and Image Trigger (IMT). The best Alert was produced by CRT with a signal-to-noise ratio of 35.5 in the 8-120 keV energy band over a time window of 20.48 s starting at Tb. The light curve shows a single broad peak of duration of about 40 s. The localization of the best Alert is RA, Dec = 45.119, 6.701 (J2000) with a 90% C.L. radius of 2.9 arcmin (including a systematic error of 2 arcmin added in quadrature). GRM light curve showed a broad peak structure with a T90 duration of about 40 s. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb241212A.png SVOM slewed automatically to the burst. MXT began observing the field at 2024-12-12T09:24:05, 133 seconds after Tb, during an exposure of 6 seconds, before SAA entry. Using onboard processed data we found one uncatalogued X-ray source located at RA, Dec 45.087, 6.719 degrees with a 90% C.L. radius of 70 arcseconds, corresponding to: RA = 03h 00m 21s Dec = 06° 43' 08" This location is 2.2 arcminutes from the ECLAIRs onboard position. VT began observing the field after the slew. The analysis of the recorded images will be published in a future circular on the follow-up of the SVOM optical instruments. Burst Advocate for this burst is Zhangli (zhangli(a)ihep.ac.cn). Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst. View this GCN Circular online at https://gcn.nasa.gov/circulars/38541. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36539] GRB 241212A: Fermi GBM Final Real-time Localization
by GCN Circulars 12 Dec '24

12 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38540 SUBJECT: GRB 241212A: Fermi GBM Final Real-time Localization DATE: 24/12/12 09:32:08 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 09:21:48 UT on 12 Dec 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241212A (trigger 755688113.6612 / 241212390). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 44.3, Dec = 6.5 (J2000 degrees, equivalent to J2000 02h 57m, 6d 30'), with a statistical uncertainty of 3.6 degrees. The angle from the Fermi LAT boresight is 40.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241212390/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241212390/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241212390/… View this GCN Circular online at https://gcn.nasa.gov/circulars/38540. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36538] GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
by GCN Circulars 12 Dec '24

12 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38539 SUBJECT: GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations DATE: 24/12/12 06:24:33 GMT FROM: Nicolai Pankov at HSE, IKI RAS <colinsergesen(a)gmail.com> N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), R. Ya. Inasaridze (AbAO) report on behalf of IKI-GRB-FuN: We performed optical observations of GRB 241209B (Xie et. al, GCN 38478; Evans, GCN 38494; Perez-Garcia et. al, GCN 38499; Qiu et. al, GCN 38516; Williams et. al, GCN 38525; DeLaunay et. al, GCN 38528; Dafcikova et. al, GCN 38534; Ridnaia et. al, GCN 38537) in the R-filter with 1.5-meter AZT-33IK telescope of Sayan observatory (Mondy) and 0.7-meter AS-32 telescope of Abastumani observatory (AbAO). The observations began at Mondy on 2024-12-10 18:11:43 UT, i.e. ~1.6 days since trigger. The optical counterpart (Xie et. al, GCN 38478) is not detected in the stacked images from both telescopes. The preliminary upper limits are given below: Date UTstart t-T0 Exp. Filter OT Err. UL Telescope (mid, days) (s) (3sigma) 2024-12-10 18:11:43 1.621802 40*120 R n/d n/d 22.1 AZT-33IK 2024-12-10 21:27:04 1.759885 87*60 R n/d n/d 20.9 AS-32 2024-12-11 20:35:13 2.722143 41*120 R n/d n/d 21.8 AZT-33IK The magnitudes were calibrated using nearby stars from USNO-B1.0 (R2 magnitudes) and are not corrected for the Galactic extinction towards the GRB 241209B. View this GCN Circular online at https://gcn.nasa.gov/circulars/38539. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36537] GRB 241209A: Chandra X-ray Detection
by GCN Circulars 11 Dec '24

11 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38538 SUBJECT: GRB 241209A: Chandra X-ray Detection DATE: 24/12/11 19:27:31 GMT FROM: Peter Blanchard at Harvard <peter.blanchard(a)cfa.harvard.edu> Peter K. Blanchard and Edo Berger (Harvard) report on behalf of a larger collaboration: We observed the short GRB 241209A (GCNs 38474, 38476) with Chandra/ACIS (Program 25500091, PI: Berger) starting at UT 2024-12-10 13:47:26 with an exposure time of 19.8 ks (mid-time of 38.4 hr post-burst). We detect a source consistent with the enhanced Swift/XRT position (GCN 38486) at the following coordinates: RA (J2000): 10:21:35.207 Dec (J2000): +06:19:42.73 with a one sigma uncertainty of 0.3” in RA and Dec. The X-ray source is closer (~0.6” away) to the fainter galaxy of the two identified by de Ugarte Postigo et al. (GCN 38484), which has a redshift of z=1.490 (GCN 38487). The source is ~2” away from the infrared source identified by Schneider et al. (GCN 38506). We thank the Chandra team for rapidly scheduling these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/38538. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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