January 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 36937] GRB 250114A: LCO optical observations
by GCN Circulars 14 Jan '25

14 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38930 SUBJECT: GRB 250114A: LCO optical observations DATE: 25/01/14 08:41:29 GMT FROM: luca.izzo(a)inaf.it D. B. Malesani (DAWN/NBI and Radboud Univ.), and L. Izzo (INAF-OACn and DARK/NBI) report: We observed the field of GRB 250114A (Klingler et al., GCN #38927) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at the Cerro Tololo, Chile. Observations started on 2025 January 14 at 07:48:10 UT (14.85 minutes after the GRB trigger). We obtained a series of 3x180 s images in the SDSS-r filter. At the location of the Swift-UVOT afterglow, we detect a faint source. We measure a preliminary magnitude of r = 20.18 +/- 0.15 mag (AB), calibrated against nearby stars from the Pan-STARRS catalog. This value is consistent with TRT observations obtained at a similar epoch (An et al., GCN #38929). This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719. View this GCN Circular online at https://gcn.nasa.gov/circulars/38930. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36936] GRB 250114A: TRT optical observations
by GCN Circulars 14 Jan '25

14 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38929 SUBJECT: GRB 250114A: TRT optical observations DATE: 25/01/14 08:35:39 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> J. An (NAOC), S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), X. Liu, Z.P. Zhu, S.Y. Fu, S.Q. Jiang, D. Xu (NAOC) report on behalf of a large collaboration: We observed the field of GRB 250114A detected by Swift (Klingler et al., GCN 38927), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Cerro Tololo, Chile. Observations started at 07:46:08.50 UTC on 2025-01-14, i.e., 13 mins after the Swift trigger, and a series of R-band frames were obtained. The optical afterglow by Swift/UVOT (Klingler et al., GCN 38927) is clearly detected in the stacked images. Its brightness is decaying and has r ~ 20.2 mag at a median time 14.5 mins after the Swift trigger, calibrated with PanSTARRS and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38929. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36935] Swift GRB 250114A: Global MASTER-Net observations report
by GCN Circulars 14 Jan '25

14 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38928 SUBJECT: Swift GRB 250114A: Global MASTER-Net observations report DATE: 25/01/14 08:25:08 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 Swift GRB 250114A ( N. J. Klingler et al., GCN 38927) errorbox 18 sec after notice time and 63 sec after trigger time at 2025-01-14 07:34:22 UT, with upper limit up to 18.2 mag. The observations began at zenith distance = 18 deg. The sun altitude is -23.6 deg. The galactic latitude b = 41 deg., longitude l = 270 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2742671 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 68 | MASTER-OAFA | C | 10 | 18.2 | 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/38928. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36934] GRB 250114A: Swift detection of a burst with an optical counterpart
by GCN Circulars 14 Jan '25

14 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38927 SUBJECT: GRB 250114A: Swift detection of a burst with an optical counterpart DATE: 25/01/14 07:50:30 GMT FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk> N. J. Klingler (GSFC/UMBC/CRESSTII), R. Brivio (INAF-OAB), J. J. DeLaunay (PSU), K. L. Page (U Leicester), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB), M. H. Siegel (PSU) and A. Tohuvavohu (Caltech) report on behalf of the Neil Gehrels Swift Observatory Team: At 07:33:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250114A (trigger=1281241). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 166.590, -15.143 which is RA(J2000) = 11h 06m 22s Dec(J2000) = -15d 08' 34" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 50 sec. The peak count rate was ~875 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 07:35:27.7 UT, 128.3 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 166.57673, -15.11138 which is equivalent to: RA(J2000) = 11h 06m 18.42s Dec(J2000) = -15d 06' 41.0" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 122 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. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (5.06 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.9 (+3.65/-3.04) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 4.84e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 136 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 11:06:18.43 = 166.57679 DEC(J2000) = -15:06:41.7 = -15.11159 with a 90%-confidence error radius of about 0.74 arc sec. This position is 3.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 20.35 with a 1-sigma error of about 0.20. No correction has been made for the expected extinction corresponding to E(B-V) of 0.056. Burst Advocate for this burst is N. J. Klingler (noelklin AT umbc.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/38927. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36933] GRB 250101A: Terskol Zeiss-2000 optical observations
by GCN Circulars 14 Jan '25

14 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38926 SUBJECT: GRB 250101A: Terskol Zeiss-2000 optical observations DATE: 25/01/14 06:25:40 GMT FROM: Nicolai Pankov at HSE, IKI RAS <colinsergesen(a)gmail.com> E. Mazaeva (IKI), N. Pankov (HSE, IKI), A. Pozanenko (IKI), N. Kapitanov (INASAN), A. Moskvitin (SAO RAS) report on behalf of the IKI-GRB-FuN collaboration: We performed optical observations of the field of GRB 250101A (Page et. al, GCN 38752; Li et. al, GCN 38753; Mohan et. al, GCN 38754; Zhu et. al, GCN 38755; Budnev et. al, GCN 38756; Wu et. al, GCN 38758; Zhu et. al, GCN 38759; Goad et. al, GCN 38761; Moskvitin et. al, GCN 38762; Odeh et. al, GCN 38763; Hu et. al, GCN 38764; Moskvitin et. al, GCN 38765; D'Avino et. al, GCN 38768; Escudero-Coca et. al, GCN 38769; Leonini et. al, GCN 38771; Dichiara et. al, GCN 38773; Zhang et. al, GCN 38774; Siegel, GCN 38775; Li et. al, GCN 38776; Komesh et. al, GCN 38777; Ghosh et. al, GCN 38779; Moskvitin et al., GCN 38780; Krimm et. al, GCN 38782; Komesh et. al, GCN 38790; Méndez-Lapido et. al, GCN 38810; Gupta et. al, GCN 38818; Ferro et. al, GCN 38831; Lin et. al, GCN 38837; Pankov et. al., GCN 38869; Pankov et. al, GCN 38890) in the R filter with the 2-meter Zeiss-2000 telescope of the Terskol observatory starting on 2025-01-01 17:27 UT, i.e. ~4.8 hours since trigger. The preliminary photometry of the optical afterglow is as follows: Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2025-01-01 17:27:31 0.19926 38*120 R 20.11 0.04 22.4 2025-01-01 21:37:20 0.35498 30*60 R 19.40 0.05 21.5 2025-01-02 14:57:45 1.07870 57*30 R 22.13 0.33 22.1 2025-01-02 21:44:44 1.35811 39*30 R 21.93 0.28 22.1 2025-01-03 18:02:09 2.22881 90*60 R n/d n/d 22.7 The photometry is based on nearby stars from the PS1 catalog (Lupton 2005 transformations). No correction has been made for the Galactic extinction. The obtained results confirm the re-brightening visible in other observations (Moskvitin et. al, GCN 38765; Pankov et. al, GCN 38890). View this GCN Circular online at https://gcn.nasa.gov/circulars/38926. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36932] EP250108a / AT 2025kg: SAO RAS optical observations
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38925 SUBJECT: EP250108a / AT 2025kg: SAO RAS optical observations DATE: 25/01/13 21:42:08 GMT FROM: Moskvitin Alexander at SAO RAS <mosk(a)sao.ru> A. S. Moskvitin and O. I. Spiridonova (SAO RAS), report on behalf of the GRB follow-up team. We observed the field of X-ray transient EP250108a detected by EP-WXT (Li et al. GCN 38861) with the SAO RAS 1-m telescope Zeiss-1000 on January 11, 17:34:02--18:47:16 UT (t_mid - T0 = 3.2362 days). We obtained 8 x 300 sec images in Rc band. The OT (Eyles-Ferris, GCN 38878; Zhu et al., GCN 38885; Malesani et al., GCN 38902; Kumar et al., GCN 38907; Zhu et al., GCN 38908, Levan et al., GCN 38909; Izzo, GCN 38912; Zou et al., GCN 38914) is marginally detected in our stacked image with the brightness of R = 20.56 +/- 0.27 (calibrated anainst nearby USNO-B1 stars and not corrected for the MW extinction). View this GCN Circular online at https://gcn.nasa.gov/circulars/38925. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36931] EP241021a: SMA radio observation
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38924 SUBJECT: EP241021a: SMA radio observation DATE: 25/01/13 15:44:13 GMT FROM: Amar Aryan at National Central University, Institute of Astronomy (NCUIA) <amararyan941(a)gmail.com> Amar Aryan (Graduate Institute of Astronomy, National Central University, Taiwan),Giorgos Michailidis (Aristotle University of Thessaloniki, Greece), Sourya Ranjan Das (Indian Institute of Space Science and Technology, India), Bhushan Kayastha (University of Chinese Academy of Sciences, China), Garrett K. Keating (Center for Astrophysics | Harvard & Smithsonian, Cambridge, USA), and Joshua Bennett Lovell (Center for Astrophysics | Harvard & Smithsonian, Cambridge, USA) report: We observed the field of the fast X-ray Transient EP 241021a (Hu et al. GCN 37834) with the Submillimeter Array (SMA) under program 2024B-S052 (PI: G. Keating) starting on 2024 Dec 25 at 03:13:33 UTC (64.92 days after the EP trigger) for 8.63 hours. Our observations were performed in “dual receiver mode”. We use "Uranus" as flux calibrator, "3c84" as bandpass calibrator and "0224+069" as gain calibrator. We did not find statistically significant emission at the position of the optical counterpart discovered by Fu et al. (GCN 37840, 37842), and the corresponding radio counterpart reported by Ricci et al. (GCN 37949), Carotenuto et al. (GCN 38014) and Schroeder et al. (GCN 38640). Thus, we estimate a 3-sigma upper limit of ~ 0.8 mJy at 235 GHz. We thank the the organizers of 2025 Submillimeter Array Interferometry School and the SMA observing staffs for scheduling and executing these observations. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. We recognize that Maunakea is a culturally important site for the indigenous Hawaiian people; we are privileged to study the cosmos from its summit. View this GCN Circular online at https://gcn.nasa.gov/circulars/38924. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36930] GRB 250113A: SVOM/GRM observation of a long burst
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38923 SUBJECT: GRB 250113A: SVOM/GRM observation of a long burst DATE: 25/01/13 14:04:20 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> SVOM/GRM team: Chen-Wei Wang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) report on behalf of the SVOM team: During the commissioning phase, SVOM/GRM was triggered in-flight by a long burst GRB 250113A (SVOM trigger reference: sb25011303) at 2025-01-13T06:24:36.900 UTC (T0). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multi-pulses with a T90 of 42 +2/-3 s. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250113A.png The SVOM/GRM on-ground localization of this burst is (J2000): RA: 321.4 deg DEC: -21.6 deg Error: 2.7 deg (1sigma, statistical only) We caution that the calibration of SVOM/GRM is undergoing and this localization is subject to systematic errors. In addition, the position of this burst, as determined by GRM, is located at about 159 degrees from the SVOM optical axis. However, we note that this GRM location is broadly consistent with the non-detection of ECLAIRs. 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/GRM point of contact for this burst is: Chen-Wei Wang (IHEP) (cwwang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/38923. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36929] GRB 250107A: VZLUSAT-2 detection
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38922 SUBJECT: GRB 250107A: VZLUSAT-2 detection DATE: 25/01/13 12:05:33 GMT FROM: Andras Pal at Konkoly Observatory <apal(a)szofi.net> A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration. The long-duration GRB 250107A (Fermi/GBM detection: GCN 38836; Swift/BAT-GUANO detection: GCN 38840; INTEGRAL/SPI-ACS peak detection at 2025-01-07 ~05:02:35 UTC) was detected by the GRB detector on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/). The data acquisition was performed by the GRB detector unit no. 1. The detection was confirmed at the peak time 2025-01-07 05:02:34 UTC. The T90 duration is 21 s and the significance during T90 reaches 9 sigma. The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB250107A_GCN_VZLUSAT2.pdf All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/ The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral. View this GCN Circular online at https://gcn.nasa.gov/circulars/38922. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36928] EP250109b: optical upper limits with the Liverpool Telescope
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38921 SUBJECT: EP250109b: optical upper limits with the Liverpool Telescope DATE: 25/01/13 12:00:00 GMT FROM: Amit Kumar at Royal Holloway - UoL/ U of Warwick, UK <amitkundu515(a)gmail.com> A. Kumar (RHUL), N. C. Sun (UCAS), J. R. Maund (RHUL), W. X. Li, Y. N. Wang (NAOC), and K. Wiersema (Herts) report: We observed the field of EP-WXT-detected transient EP250109b (Cheng et al., ATel #16974) using the IO:O imager on the 2m Liverpool Telescope. Observations were carried out between 2025-01-10 UT 23:39:42 and 2025-01-11 UT 01:02:34, corresponding to ~1.65 and ~1.71 days post-trigger, respectively, in the g, r, and z bands. In each band, 3×600s exposures were obtained. However, the g- and z-band frames were affected by trailing and are unsuitable for analysis. In the stacked r-band image (at ~1.67 days post-trigger), no new, uncatalogued source was detected within the EP-FXT localization uncertainty region (Cheng et al., ATel #16974), down to a limiting magnitude of r > 21.8 (AB). This circular may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/38921. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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vsnet-grb-info January 2025