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

[vsnet-grb-info 37097] GRB 250128B: Gemini-North optical extended source detection
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39088 SUBJECT: GRB 250128B: Gemini-North optical extended source detection DATE: 25/01/29 21:19:48 GMT FROM: Jillian Rastinejad at Northwestern Univ. <jillianrastinejad2024(a)u.northwestern.edu> Jillian Rastinejad, Wen-fai Fong (Northwestern), Genevieve Schroeder (Cornell), Harsh Kumar (CfA), Benjamin Gompertz (Birmingham) and Andrew Levan (Radboud) report on behalf of a larger collaboration: We observed the location of the X-ray counterpart of the short GRB 250128B (Evans et al., GCN 39058) with the Gemini Multi-Object Spectrograph (GMOS) mounted on Gemini-North under Program GN-2024B-Q-111 (PI: Fong). We obtained 13x120-sec imaging in r-band at a mid-time of 2025-01-29 14:43:45.0 UT (0.93 days post-burst), at a median airmass of 1.3 and seeing of 1’’. Within the enhanced XRT localization (Evans et al., GCN 39069), we detect a faint extended source, or possibly a blend of two unrelated sources. This source complex is centered at R.A. = 15:25:42.07, Decl. = -00:32:20.3 (J2000) with an approximate visual angular size of 2”, and is consistent with the position of the candidate near-IR source reported by Yang et al., GCN 39084. Both positions are consistent with the enhanced XRT localization (Evans et al., GCN 39069). Calibrated to SDSS, we measure a preliminary brightness for this source complex of r = 25.4 +/- 0.2 AB mag, not corrected for Galactic extinction. We do not detect any other sources within or adjacent to the XRT localization to a 3-sigma limiting magnitude of r > 25.8 AB mag. At this stage, we cannot make any determination if there is any contribution to the observed light from an afterglow component. Further observations are planned to monitor the variability of the source. We thank Jennifer Andrews and additional Gemini staff for the rapid planning and execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39088. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37096] The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39087 SUBJECT: The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare DATE: 25/01/29 20:04:00 GMT FROM: Weikang Zheng at UC Berkeley <weikang(a)berkeley.edu> WeiKang Zheng (UCB), Xuhui Han (NAOC), Pinpin Zhang (NAOC) and Alexei V. Filippenko (UCB) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, automatically responded to the EP-WXT trigger (ID= 01709131085; Li et al., GCN 39068) starting at 05:09 UT, Jan. 29th, ~20 minutes after the trigger. A set of images with 20s exposure time were obtained in B, V, R I and clear (roughly R) filters. Observations lasted for about 3 hours. The high proper motion star RX J0448.7+1003 reported by Li et al. (GCN 39068) was covered by KAIT images. Photometry of the star show that its brightness is at B~13.2 mag in our first B band image at 26.7 minutes, increased to a peak of B~12.9 mag at 43.6 minutes, then decreased afterward with B~13.6 mag at 187 minutes. We therefore confirm that this EP-WXT trigger event is truly associated with this stellar flare. View this GCN Circular online at https://gcn.nasa.gov/circulars/39087. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37095] GRB 250128B: TNG optical upper limit
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39086 SUBJECT: GRB 250128B: TNG optical upper limit DATE: 25/01/29 16:17:05 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> A. Rossi (INAF-OAS), R. Brivio, M. Ferro, P. D’Avanzo, S. Covino, D. Fugazza (INAF-OAB), L. Di Fabrizio, G. Mainella (INAF-TNG) report on behalf of the CIBO collaboration: We observed the field of the short GRB 250128B detected by Fermi and Swift (Fermi GBM team, GCN 39057; Evans et al., GCN 39058) with the Italian 3.6m TNG telescope equipped with the optical camera DOLORES. A series of images were obtained with the i-sdss filter on 2025-01-29 at a mid-time of about 13.5 hours after the burst. No clear afterglow candidate is detected within the UVOT-enhanced XRT position (Evans et al., GCN 39069) down to a 3-sigma limiting magnitude of i ~ 25.3 (AB; calibrated against the Pan-STARRS catalogue). View this GCN Circular online at https://gcn.nasa.gov/circulars/39086. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37094] GRB 250129A: Swift/UVOT Detection
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39085 SUBJECT: GRB 250129A: Swift/UVOT Detection DATE: 25/01/29 14:51:44 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18(a)psu.edu> M. H. Siegel (PSU) and A. P. Beardmore (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250129A 1185 s after the BAT trigger (Beardmore et al., GCN Circ. 39066). A source consistent with the XRT position (Goad et al., GCN Circ. 39082) and the previously reported optical counterpart (Francile et al., GCN Circ. 39065; Belkin et al, GCN Circ. 39072; Ghosh et al., GCN Circ 39077; Schneider et al. GCN Circ. 39078, Brivio et al., GCN Circ. 39079.) is detected in the initial UVOT exposures. The UVOT light curve shows some evidence of fading. The lack of detection of this bright burst in the NUV filters would be consistent with the redshift of 2.15 reported by Schneider et al. (GCN Circ, 39071) and Izzo et al. (GCN Circ. 39073). The preliminary UVOT position is: RA (J2000) = 13:14:42.41 = 198.67670 (deg.) Dec (J2000) = +05:01:50.3 = 5.03064 (deg.) with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence). Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white (fc) 1185 1335 147 17.43+/-0.04 white 1468 1835 58 17.39+/-0.07 white 5450 5650 196 17.63+/-0.04 v 1343 1885 77 17.24+/-0.17 v 10957 11667 690 17.98+/-0.08 b 1444 1809 58 17.29+/-0.11 b 5245 16960 649 17.63+/-0.04 u 1418 1785 38 16.93+/-0.15 uvw2 5656 5845 186 >19.77 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.037 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/39085. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37093] GRB 250128B: VLT/HAWKI near-infrared observations
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39084 SUBJECT: GRB 250128B: VLT/HAWKI near-infrared observations DATE: 25/01/29 14:09:47 GMT FROM: Yu-Han Yang at University of Rome Tor Vergata <yyang(a)roma2.infn.it> Yu-Han Yang (U Rome), Muskan Yadav (U Rome), Rosa L. Becerra (U Rome), Simone Dichiara (PSU), Eleonora Troja (U Rome) and Roberto Ricci (U Rome) report: We observed the field of GRB 250128B (Evans et al., GCN 39058, Myers et al., GCN 39063) with the HAWKI imager on the ESO VLT UT4 (Yepun). Observations began 0.68 days after the trigger and were carried out in the J filter at an average seeing of 1.3". Based on a preliminary analysis, we do not detect any new source within the XRT afterglow position (Evans et al., GCN 39069) down to J > 24 AB mag (3 sigma), calibrated using nearby stars in the 2MASS catalogue. A low-significance (~2 sigma) source is identified at RA, Dec (J2000) = 15:25:42.11, -0.32:21.21. Further observations to determine the significance and possible variability of this source are planned. We thank the staff at the VLT, for the rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39084. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37092] GRB 250127A: CrAO and Terskol optical upper limits
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39083 SUBJECT: GRB 250127A: CrAO and Terskol optical upper limits DATE: 25/01/29 13:11:18 GMT FROM: Nicolai Pankov at HSE, IKI RAS <colinsergesen(a)gmail.com> N. Pankov (HSE, IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), I. Sokolov (INASAN) report on behalf of the IKI-GRB-FuN: We performed optical observations of the field of GRB 250127A (Wu et. al, GCN 39041; Turpin et. al, GCN 39043; Evans, GCN 39044; Xin et. al, GCN 39047; Yin et. al, GCN 39053; Kennea et. al, GCN 39056) in the R-filter using the 2.6-meter ZTSh telescope of the Crimean Astrophysical Observatory (CrAO), and in Clear light with the 0.8-meter K-800 telescope of the Terskol Observatory (INASAN). The observations began on 2025-01-27 23:27 UT, i.e. ~0.022 days since SVOM trigger. We do not detect any new sources spatially consistent with the X-Ray afterglow position reported by the Swift XRT team (Kennea et. al, GCN 39056) and the EP-FXT team (Yin et. al, GCN 39053). The preliminary upper limits are given below: Date UT start t-T0 Exp. Filter UL(3sigma) Telescope (mid, days) (s) 2025-01-27 23:27:51 0.02251 87*30 Clear 18.2 K-800 2025-01-28 00:08:00 0.80364 14*120 R 23.7 ZTSh The photometry has calibrated using nearby stars from the USNO-B1.0 catalog (R2 magnitudes). No correction has been made for the Galactic extinction A_R = 0.119 (Schlegel & Finkbeiner, 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/39083. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37091] GRB 250129A: Enhanced Swift-XRT position
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39082 SUBJECT: GRB 250129A: Enhanced Swift-XRT position DATE: 25/01/29 12:57:34 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 809 s of XRT Photon Counting mode data and 1 UVOT images for GRB 250129A, 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 = 198.67662, +5.03073 which is equivalent to: RA (J2000): 13h 14m 42.39s Dec (J2000): +05d 01' 50.6" 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/39082. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37090] GRB 250128B: NOT optical upper limit
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39081 SUBJECT: GRB 250128B: NOT optical upper limit DATE: 25/01/29 12:03:24 GMT FROM: Daniele B. Malesani at IMAPP / Radboud University <d.malesani(a)astro.ru.nl> K. E. Heintz (DAWN/NBI), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. de Ugarte Postigo (CNRS, OCA and LAM), Benjamin N. Hauptmann (NOT, DTU Space), Arthur M. Kadela (NOT, NBI), report on behalf of a larger collaboration: We observed the field of the short Fermi and Swift GRB 250128B (Fermi GBM team, GCN 39057; Evans et al., GCN 39058) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Three exposures by 300 s each were secured in the r band, with a mean epoch 2025 Jan 29.2095 UT (12.65 hr after the trigger). The sequence was interrupted in order to observe GRB 250129A (Izzo et al., GCN 39073). No source is detected within or close to the UVOT-enhanced XRT position (Evans et al., GCN 39069), down to a 3-sigma limiting AB magnitude r > 23.45, calibrated against nearby stars from the Pan-STARRS catalog. View this GCN Circular online at https://gcn.nasa.gov/circulars/39081. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37089] GRB 250128B: VLT/FORS2 optical observations
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39080 SUBJECT: GRB 250128B: VLT/FORS2 optical observations DATE: 25/01/29 11:39:39 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> Rosa L. Becerra (U Rome), Yu-Han Yang (U Rome), Simone Dichiara (PSU), Eleonora Troja (U Rome) and Roberto Ricci (U Rome) report: We observed the field of GRB 250128B (Evans et al., GCN 39058, Myers et al., GCN 39063) with the FORS2 imager on the ESO VLT UT1 (Antu). Observations began 0.67 days after the trigger and were carried out in the R filter at an average seeing of 1.1". We do not detect any new source at the XRT source position (Evans et al., GCN 39069) down to the following 3-sigma limit R>24.8 AB mag calibrated using nearby stars in the PanSTARRS PS1 DR2 catalogue. In our image we identify a few extended objects close to the XRT localization, however their probability of chance coincidence is Pcc>20 %. We thank the staff at the VLT, especially Steffen Mieske, for the rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39080. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37088] GRB 250129A: REM optical/NIR afterglow detection
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39079 SUBJECT: GRB 250129A: REM optical/NIR afterglow detection DATE: 25/01/29 11:27:01 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.), M. De Pasquale (Univ. of Messina), L. Izzo (INAF-OACn and DARK/NBI), A. Melandri (INAF-OAR), G. Tagliaferri, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 250129A detected by Swift (Beardmore et al., GCN 39066) 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 2025 January 29 at 04:47:12 UT (i.e. 123 s after the Swift trigger), and lasting for about 4 hours. From preliminary photometry we detect the counterpart in the optical and NIR images at the position of the optical afterglow (Francile et al., GCN 39065; Schneider et al., GCN 39071; Belkin et al., GCN 39072; Izzo et al., GCN 39073; Izzo & Malesani, GCN 39074; Gosh et al., GCN 39077; Schneider et al., GCN 39078) with the following early-time magnitudes: r = 17.7 +/- 0.3 (AB; calibrated against the Pan-STARRS catalogue) at a mid-time of t - t0 = 128 s after the trigger. H = 15.3 +/- 0.3 (Vega; calibrated against the 2MASS catalogue) at a mid-time t - t0 = 175 s after the trigger. Our light curve spans between t0 + 128 s and t0+15120 s. It peaks around t0+2300 s and shows a rebrightening around t0+14300 s. View this GCN Circular online at https://gcn.nasa.gov/circulars/39079. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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