December 2024 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[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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