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

[vsnet-grb-info 37107] GRB 250129A: TNG NIR afterglow detection
by GCN Circulars 30 Jan '25

30 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39098 SUBJECT: GRB 250129A: TNG NIR afterglow detection DATE: 25/01/30 13:08:07 GMT FROM: Matteo Ferro at INAF-OAB <matteo.ferro(a)inaf.it> M. Ferro, R. Brivio, P. D'Avanzo, S. Covino (INAF-OAB), A. Rossi (INAF-OAS), D. B. Malesani (DAWN/NBI & Radboud Univ.), A. Melandri (INAF-OAR), G. Mainella e M. Cecconi (INAF-TNG) on behalf of the CIBO collaboration report: We observed the field of the GRB250129A detected by the Swift (Beardmore et al., GCNC 36556) with the Italian 3.6m TNG telescope equipped with the near-infrared camera NICS to follow up its afterglow. A series of images were obtained with the J and H filters starting on 2025-01-30T06:16:34 UT (i.e. 25.5 hours post T0). The afterglow (Lipunov et al., GCN 39070; Schneider et al., GCN 39071; Gompertz et al., GCN 39072; Izzo et al., GCN 39073; Izzo et al., GCN 39074; Francile et al., GCN 39075; Ghosh et al., GCN 39077; Schneider et al., GCN 39078; Brivio et al., GCN 39079; Heintz et al., GCN 39081; Siegel et al., GCN 39085; Zheng et al., GCN 39090; Schlekat et al., GCN 39091; Antier et al., GCN 39096; Odeh et al., GCN 39097) is detected in the co-added image with a preliminary result of H(Vega)~16.7 mag (calibrated against the 2MASS catalogue). View this GCN Circular online at https://gcn.nasa.gov/circulars/39098. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37106] GRB 250129A: AKO Optical Afterglow Detection
by GCN Circulars 30 Jan '25

30 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39097 SUBJECT: GRB 250129A: AKO Optical Afterglow Detection DATE: 25/01/30 11:41:15 GMT FROM: Mohammad Odeh at Al Khatim Observatory M44 <mshodeh(a)gmail.com> Mohammad Odeh (Al-Khatim Observatory, AKO, operated by the International Astronomical Center in Abu Dhabi, UAE), and Shaikha Alshamsi, Nuha Manal Pattani, and Nidhal Guessoum (American University of Sharjah, UAE), report: We observed the field of GRB 250129A (Beardmore et al., GCN 39066) using our 0.36m f/7.7 robotic telescope. The observation session began on 29 January 2025 at 21:07 UT and continued until 22:02 UT, with a midpoint at 21:36 UT, approximately 16.8 hours after the trigger. We obtained multiple 180-second exposures using the Ic filter. The optical afterglow was clearly detected at: R.A. (J2000): 13:14:42.40 Dec. (J2000): +05:01:50.4 Our detection is consistent with the results of Francile et al., GCN 39065; Beardmore et al., GCN 39066; Schneider et al., GCN 39071; Belkin et al., GCN 39072; Izzo et al., GCN 39073; Izzo & Malesani, GCN 39074; Ghosh et al., GCN 39077; Schneider et al., GCN 39078; Brivio et al., GCN 39079; Siegel et al., GCN 39085; Zheng et al., GCN 39090; Schlekat et al., GCN 39091; Antier et al., GCN 39096. The following observation was calculated using the Atlas catalogue as a reference: ---------------------------------------------------------------------------- - ObsTime (mid), Exposure (sec), Filter, Mag ---------------------------------------------------------------------------- - 2025-01-29T21:35:48Z, 18 x 180s (stacked), Ic, 18.7 +/- 0.22 ---------------------------------------------------------------------------- - The magnitude is not corrected for galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/39097. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37105] GRB 250129A: GRANDMA/TAROT optical afterglow detection
by GCN Circulars 30 Jan '25

30 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39096 SUBJECT: GRB 250129A: GRANDMA/TAROT optical afterglow detection DATE: 25/01/30 10:05:34 GMT FROM: Patrice Hello at IJCLAB, Orsay <patrice.hello(a)ijclab.in2p3.fr> S. Antier (OCA/IJCLAB), P. Hello (IJCLAB), P. Gokuldass (ERAU), A. Klotz (IRAP), C. Limonta, M. Boer, Q. Andre, A. Durroux (OCA), N. Guessoum (AUS), Haowei Peng (Tsinghua), C. Andrade, M. Coughlin (UMN), P-A Duverne (APC), S. Karpov (FZU), T. Pradier (Unistra/IPHC), D. Turpin (CEA-Saclay/Irfu) on behalf of the GRANDMA collaboration: we observed the field of GRB 250129A, detected by Swift (Beardmore et al., GCN 39066) using TAROT/TCH and TAROT/TCA. Observations began 1 min after T0 without filter, and we took a series of images with various exposure times from 1.76 min to 73 min post T0. We detected the optical afterglow candidate in he first (earliest) measurement with TAROT/TCH (5x30s exposure time) at T0+2.96min with mag=17.48 +/- 0.08 (in R band). The data were reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022), using Skymapper for reference. Processing of remaining data is ongoing. Our measurements are compatible with early measurements, GCNs 39070, 39072, 39073, 39074, 39078, 39079. 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/39096. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37104] GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
by GCN Circulars 30 Jan '25

30 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39095 SUBJECT: GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading DATE: 25/01/30 09:08:18 GMT FROM: Damien Turpin at CEA-Saclay <dturpin-astro(a)hotmail.com> Y.-H. I. Yin (NJU), Y. L. Wang, H. N. Yang, H. Y. Liu (NAO, CAS), Z. Y. Liu, M. Q. Huang (USTC), Z. X. Ling, Y. Liu (NAO, CAS), B. Cordier, D. Turpin (CEA) on behalf of the Einstein Probe team: We performed a second follow-up observation of GRB 250127A (SVOM, Wu et al., GCN 39041) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The observation started at 2025-01-29 09:55:45 (UTC) with ~ 4.9 ks of exposure in total. The uncatalogued x-ray source detected by both Swift/XRT (Source 2, Kennea et al., GCN 39056) and EP-FXT (Yin et al. GCN 39053) is no longer detected in our second EP-FXT epoch. Assuming Galactic equivalent hydrogen column density of 4.52 x 10^20 cm^-2 and a photon index of 2.0, the upper limit of the 0.5-10 keV flux is estimated to be 1.93 x 10^-14 erg/s/cm^2. The fading behavior of the x-ray source identified by Yin et al. GCN 39053 and Kennea et al., GCN 39056, confirms it as being the afterglow of GRB 250127A. 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/39095. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37103] GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
by GCN Circulars 30 Jan '25

30 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39094 SUBJECT: GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits DATE: 25/01/30 07:15:01 GMT FROM: Nicolai Pankov at HSE, IKI RAS <colinsergesen(a)gmail.com> A. S. Moskvitin (SAO RAS), N. Pankov (HSE, IKI), O. Spiridonova (SAO RAS), V. Rumyantsev (CrAO), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of the collaboration between IKI-GRB-FuN and the GRB follow-up team. We observed the field of GRB 250128B (Fermi GBM team, GCN 39057; Evans et al., GCN 39058; Myers and Meegan, GCN 39063; Osborne et al., GCN 39064) with the 1-meter Zeiss-1000 telescope at the Special Astrophysical Observatory (SAO RAS) and the 2.6-meter Shajn telescope (ZTSh) at Crimean Astrophysical Observatory (CrAO). The observations began on 2025-01-29 00:57:27 at the SAO RAS, i.e. ~0.38 days since the burst. We obtained 12 x 300 sec images in the Rc-filter with Zeiss-1000 and 44 x 120 sec images in the R-filter with ZTSh. The stacked images from both telescopes have not revealed any new optical source located within the enhanced XRT circle (Evans et al., GCN 39069). The preliminary upper limits are as follows: Date UT start t-T0 Exp. Filter UL(3sigma) Telescope (mid, days) (s) 2025-01-29 00:57:27 0.38090 12*300 Rc 23.5 Zeiss-1000 2025-01-29 01:33:22 0.41284 44*120 R 23.1 ZTSh The photometry is based on nearby stars of the USNO-B1.0 catalog (R2 magnitudes) and have not been corrected for the Galactic extinction. Our results are consistent with the upper limits obtained by other teams (Izzo & Malesani, GCN 39059; Lipunov et al., GCN 39061; GCN 39067; Ulaczyk et al., GCN 39062; Adami et al., GCN 39076; Becerra et al., GCN 39080; Heintz et al., GCN 39081; Yang et. al, GCN 39084; Rossi et. al, GCN 39086). View this GCN Circular online at https://gcn.nasa.gov/circulars/39094. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37102] GRB 250128B: VLA radio upper limit
by GCN Circulars 30 Jan '25

30 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39093 SUBJECT: GRB 250128B: VLA radio upper limit DATE: 25/01/30 06:35:37 GMT FROM: Eleonora Troja <nora.gsfc(a)gmail.com> Roberto Ricci (U Rome), Muskan Yadav (U Rome), Rosa L. Becerra (U Rome), Yu-Han Yang (U Rome) and Eleonora Troja (U Rome) report: We observed the field of the short GRB 250128B discovered by Fermi/GBM (Fermi GMB team, GCN 39057) and Swift/BAT (Evans et al. GCN 39058) with the Very Large Array at the centre frequency of 6 GHz (C band) with a bandwidth 4 GHz. The observations started on 2025-01-29 at 12:48 UT and lasted for 47 mins, resulting in a mid elapsed time of 20.8 hours after trigger. The primary calibrator was 3C286 and the phase calibrator J1546+0026. Within the enhanced Swift/XRT position (Evans et al., GCN 39069) no counterpart is found down to a 3-sigma upper limit of 15 microJy. Additional follow-up is planned. We thank the VLA staff for promptly observing the target. View this GCN Circular online at https://gcn.nasa.gov/circulars/39093. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37101] Ep250125A: 1.3m DFOT optical upper limit
by GCN Circulars 30 Jan '25

30 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39092 SUBJECT: Ep250125A: 1.3m DFOT optical upper limit DATE: 25/01/30 05:24:36 GMT FROM: ANSHIKA GUPTA at ARIES <anshika05180(a)gmail.com> Anshika Gupta, Amit K. Ror, Divyanshu, Kuntal Mishra, and Shashi B. Pandey (ARIES) report: We observed the field of Ep250125A detected by EP-WXT trigger ( Wu et al. 2025, GCN 39028) with the 1.3m Devasthal Fast Optical Telescope (DFOT), located at the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2025-01-25 at 22:27:28 UT, i.e., ~ 19.83 hours after the EP-WXT trigger. We have taken multiple frames with an exposure time of 300 s in the R filter. We stacked the images after the alignment. We could not detect the optical emission in our stacked image within the error box of the EP-WXT telescope (Wu et al. 2025, GCN 39028) and Swift-XRT (Kennea et al. 2025, GCN 39029). We obtain the following 3-sigma upper limit in the stacked image: Date Start_UT T_start-T0 (hour) Filter Exp time (s) Magnitude ========================================================= 2025-01-25 22:27:28 ~19.83 R 300s*24 >22.8 The non-detection of the burst is consistent with the upper limits reported by Aryan et al. 2025, GCN 39032. The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalogue. This circular may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39092. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37100] GRB 250129A: Skynet optical observations
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39091 SUBJECT: GRB 250129A: Skynet optical observations DATE: 25/01/29 23:18:26 GMT FROM: dschlekat(a)unc.edu Donovan Schlekat, Dylan Dutton, Daniel Reichart, Joshua Haislip, and Vladimir Kouprianov report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill. We observed the field of GRB 250129A with two of Skynet's PROMPT telescopes located at the Cerro Tololo Inter-American Observatory. The observation began at 05:12:20 UT on January 29 2025, roughly 27 minutes after the Swift-BAT trigger (Beardmore et al., GCN 39066). Observations were performed in the B, V, R, and I bands. Exposure lengths were calculated using our automated exposure length scaling model. We detect the optical afterglow consistent with the coordinates reported by other facilities (Francile et al., GCN 39065; Beardmore et al., GCN 39066; Schneider et al., GCN 39071; Belkin et al., GCN 39072; Izzo et al., GCN 39073; Izzo & Malesani, GCN 39074; Ghosh et al., GCN 39077; Schneider et al., GCN 39078; Brivio et al., GCN 39079; Siegel et al., GCN 39085; Zheng et al., GCN 39090). The coordinates are: R.A. (J2000): 13:14:42.39 Dec. (J2000): 05:01:50.22 We detect the object in the B, V, R, and I band. The initial detection photometry for each band is reported below. Additional Skynet observations are ongoing. Tmid - T0 (s)| Telescope | Filter | Exposure (s) | Mag | Mag Error ------------------------------------------------------------------ 1674.49 | PROMPT-5 | B | 59 | 17.525 | 0.051 1678.99 | PROMPT-6 | V | 34 | 16.902 | 0.054 1711.99 | PROMPT-6 | R | 22 | 16.628 | 0.057 1938.49 | PROMPT-6 | I | 19 | 16.111 | 0.095 Our images have been calibrated using stars from the APASS catalog. Magnitudes were not corrected for dust extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/39091. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37099] GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39090 SUBJECT: GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours DATE: 25/01/29 22:21:18 GMT FROM: Weikang Zheng at UC Berkeley <weikang(a)berkeley.edu> WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to GRB 250129A detected by Swift (Beardmore et al., GCN 39066) starting at 09:25 UT, ~4.68h after the bust. Observations were performed in the clear (roughly R) filter with a set of 60s exposures and lasted for ~2.2h. The optical afterglow (Francile et al., GCN 39065; Beardmore et al., GCN 39066; 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; Brivio et al., GCN 39079; Siegel et al., GCN 39085) was clearly detected in every individual image. Our photometry results show that the OT rebrightened since ~4.68h (~16.7 mag) and reached a double peak at ~4.99h (~16.3 mag) and again at 5.2h (~16.3 mag), then decayed afterword, with small flares during decay phase, till ~17.1 mag at ~6.90h. View this GCN Circular online at https://gcn.nasa.gov/circulars/39090. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37098] GRB 250129A: Swift-XRT refined Analysis
by GCN Circulars 29 Jan '25

29 Jan '25

TITLE: GCN CIRCULAR NUMBER: 39089 SUBJECT: GRB 250129A: Swift-XRT refined Analysis DATE: 25/01/29 22:15:26 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), M. A. Williams (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 10 ks of XRT data for GRB 250129A, from 147 s to 46.4 ks after the BAT trigger. The data comprise 10 s in Windowed Timing (WT) mode (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=3.64 (+1.35, -0.10). At T+1185 s the decay flattens to an alpha of 0.15 (+/-0.07) before breaking again at T+23.0 ks to a final decay with index alpha=2.2 (+0.7, -0.6). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.92 (+0.16, -0.10). The best-fitting absorption column is consistent with the Galactic value of 2.4 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 3.4 x 10^-11 (3.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 2.4 x 10^20 cm^-2 Intrinsic column: 2 (+/-38) x 10^20 cm^-2 at z=2.151 Photon index: 1.92 (+0.16, -0.10) If the light curve continues to decay with a power-law decay index of 2.2, the count rate at T+24 hours will be 0.011 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.8 x 10^-13 (4.0 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/01285812. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39089. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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