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

[vsnet-grb-info 37126] GRB 250201A: INTEGRAL SPI/ACS detection
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39117 SUBJECT: GRB 250201A: INTEGRAL SPI/ACS detection DATE: 25/02/01 19:34:25 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), Lorenzo Natalucci(a,b), Luigi Piro(a) report: GRB 250201A was discovered by Fermi/GBM (GCN 39112) on 2025-02-01T09:59:46 (UTC). We searched for a corresponding counterpart in the INTEGRAL/SPI-ACS data. In an SPI-ACS light curve above 80 keV, we find a signal temporally coincident with the GBM detection, having an approximate duration of ~ 20 sec. The signal consists of two pulses over this duration. The approximate peak count rate in SPI-ACS is 77,500 cts/s for E>80 keV, over a median background rate of 62,800 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/39117. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37125] Konus-Wind detection of GRB 250129A
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39116 SUBJECT: Konus-Wind detection of GRB 250129A DATE: 25/02/01 17:29:52 GMT FROM: Dmitry Frederiks at Ioffe Institute <fred(a)mail.ioffe.ru> D. Frederiks, A.Lysenko, A. Ridnaya, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long GRB 250129A (Swift detection: Beardmore et al., GCN 39066) was detected by Konus-Wind (KW) in the waiting mode. A Bayesian block analysis of the KW waiting mode data in the 20-400 keV band reveals a >6 sigma count rate increase in the interval from T0-66 s to T0+208 s where T0 = T0(BAT) = 04:45:09 UT. The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB250129A/ Modeling the time-integrated spectrum of the burst by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.74 (-0.07, + 0.07) and Ep = 66(-8,+8) keV. In the 10 keV -10 MeV band, standard for the KW analysis, the burst fluence is (6.71 ± 0.14)x10^-6 erg/cm^2 and the 2.944 s peak energy flux is (1.46 ± 0.18)x10^-7 erg/cm^2/s. Assuming the redshift z=2.151 (Schneider et al., GCN 39071) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the burst isotropic energy release E_iso to (7.7 ± 0.2)x10^52 erg, the isotropic peak luminosity L_iso to (5.3 ± 0.7)x10^51 erg/s, and the rest-frame peak spectral energy Ep,z to (207 ± 22) keV. With the obtained estimates, GRB 250129A is consistent with 68% prediction bands of 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021), see http://www.ioffe.ru/LEA/GRBs/GRB250129A/GRB250129A_rest_frame.pdf All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/39116. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37124] GRB 250129A: 1.3m DFOT Optical observations
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39115 SUBJECT: GRB 250129A: 1.3m DFOT Optical observations DATE: 25/02/01 17:07:56 GMT FROM: Amit Kumar Ror at ARIES <mitturor77894(a)gmail.com> Amit K. Ror, Anshika Gupta, Kiran, Shashi B. Pandey, Kuntal Mishra (ARIES) report: We observed the field of GRB 250129A detected by the Swift Burst Alert Telescope (Swift team, Beardmore et al. 2025; GCN 39066) 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 2025-01-30 at 22:57:11 UT, i.e., ~ 1.76 days after the Swift-BAT 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 detected an optical afterglow in our stacked image within the error box of the enhanced Swift-XRT position by Goad et al. 2025 (GCN 39082). Further observations of the burst are still ongoing. We obtain the following preliminary magnitude in the stacked image: Date Start_UT T_start-T0 (days) Filter Exp time (s) Magnitude ========================================================= 2025-01-30 22:57:11 ~1.76 R 300s*12 19.52 +/- 0.03 Our detection is consistent with Francile et al. 2025 (GCN 39065); Lipunov et al. 2025 (GCN 39070); Schneider et al. (GCN 39071); Belkin et al. 2025 (GCN 39072); Izzo et al. 2025 (GCN 39073); Izzo et al. 2025 (GCN 39074); Francile et al. 2025 (GCN 39075); Ghosh et al. 2025 (GCN 39077); Schneider et al. 2025 (GCN 39078); Brivio et al. 2025 (GCN 39079); Siegel et al. 2025 (GCN 39085); Zheng et al. 2025 (GCN 39090); Schlekat et al. 2025 (GCN 39091); Antier et al. 2025(GCN 39096); Odeh et al. 2025 (GCN 39097); Ferro et al. 2025(GCN 39098); Bochenek et al. 2025 (GCN 39099);Malesani et al. 2025 (GCN 39100); Romanov et al. 2025 (GCN 39101); Zheng et al. 2025 (GCN 39102); Zheng et al. 2025 (GCN 39102); Watson et al. 2025 (GCN 39104); Vinko et al. 2025(GCN 39105); Akl et al. 2025 (GCN 39106); Moskvitin et al. 2025 (GCN 39107); Giovanni et al. 2025 (GCN 39109); Schlekat et al. 2025 (GCN 39110) and Schlekat et al. 2025 (GCN 39114). 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/39115. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37123] GRB 250129A: Liverpool Telescope observations suggest continued engine activity
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39114 SUBJECT: GRB 250129A: Liverpool Telescope observations suggest continued engine activity DATE: 25/02/01 13:22:21 GMT FROM: Ben Gompertz at U of Birmingham <b.gompertz(a)bham.ac.uk> B. P. Gompertz (U. Birmingham), D. B. Malesani (DAWN/NBI and Radboud), R. Brivio (INAF-OAB) and A. J. Levan (Radboud) report on behalf of a larger collaboration: We initiated follow-up observations of GRB 250129A (Beardmore et al., GCN 39066) with the IO:O camera on the 2m robotic Liverpool Telescope (LT). Observations were taken across the nights of 2025-01-30 and 2025-01-31, consisting of 5x180 s exposures in each of the SDSS r and i filters. In a preliminary analysis, we measure the following AB magnitudes: t-t0(d) exp(s) filt mag error 2.06 900 r 20.29 0.04 2.93 900 r 20.40 0.05 Magnitudes are calibrated against nearby Pan-STARRS stars and are not corrected for galactic extinction. Our measurements indicate either minimal evolution between 2 and 3 days after trigger, or a continuation of the flaring behaviour observed during the first 24 hours, as noted by Belkin et al. (GCN 39072), Francile et al. (GCN 39075), Brivio et al. (GCN 39079), Zheng & Filippenko (GCN 39090), Antier et al. (GCN 39096), and Malesani et al. (GCN 39100). View this GCN Circular online at https://gcn.nasa.gov/circulars/39114. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37122] GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39113 SUBJECT: GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417) DATE: 25/02/01 10:53:32 GMT FROM: Jochen Greiner at MPE <jcgrog(a)mpe.mpg.de> T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 760096791 at 09:59:46 on 01 Feb. 2025 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position is: RA(2000.0) = 112.5 deg Decl.(2000.0) = -54.7 deg The 1 sigma statistical error radius is 2.0 deg. We estimate an additional systematic error of 1 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB250201417/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB250201417/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB250201417/json View this GCN Circular online at https://gcn.nasa.gov/circulars/39113. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37121] GRB 250201A: Fermi GBM Final Real-time Localization
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39112 SUBJECT: GRB 250201A: Fermi GBM Final Real-time Localization DATE: 25/02/01 10:10:18 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 09:59:46 UT on 1 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250201A (trigger 760096791.667376 / 250201417). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 115.8, Dec = -52.6 (J2000 degrees, equivalent to J2000 07h 43m, -52d 36'), with a statistical uncertainty of 1.1 degrees. The angle from the Fermi LAT boresight is 17.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250201417/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250201417/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250201417/… View this GCN Circular online at https://gcn.nasa.gov/circulars/39112. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37120] LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39111 SUBJECT: LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations DATE: 25/02/01 06:33:44 GMT FROM: Satoshi Sugita at Aoyama Gakuin U. <sugita(a)phys.aoyama.ac.jp> S. Sugita, M. Serino, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU) H. Negoro, M. Nakajima, K. Takagi (Nihon U.), N. Kawai, T. Mihara, (RIKEN), report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary merger candidate S250201i at 2025-02-01 02:08:41.292 UTC. At the trigger time of S250201i, the high-voltage of MAXI/GSC was off, and it was turned on at T0+844 sec (+14.1 min). The first one-orbit (92 min) scan observation with GSC after the event covered 98% of the 90% credible region of the bayestar skymap from 03:09:42 to 03:22:16 UTC (T0+3661 to T0+4415 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email. View this GCN Circular online at https://gcn.nasa.gov/circulars/39111. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37119] GRB 250129A: Skynet Continued Optical Observations
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39110 SUBJECT: GRB 250129A: Skynet Continued Optical Observations DATE: 25/02/01 03:46:26 GMT FROM: dschlekat(a)unc.edu Donovan Schlekat, Dylan Dutton, Daniel Reichart, Joshua Haislip, Vladimir Kouprianov, Daryl Janzen, Arie Verveer, and John Kennewell report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill. We continued to observe the optical counterpart of GRB 250129A (Beardmore et al., GCN 39066) with two of Skynet’s 0.4m PROMPT telescopes at the Cerro Tololo Inter-American Observatory, Skynet’s 0.4m PROMPT telescope located in Meckering, Australia, and a 0.5m telescope at the Astronomical Observatory of the Jagiellonian University in Krakow, Poland. The observations began ~14 hours after the trigger and ended ~60 hours after the trigger. We detected the optical transient in both the V and R bands. The observed position of the optical counterpart was consistent with the coordinates described in other reports (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 & Filippenko, GCN 39090; Schlekat et al., 39091; Antier et al., 39096; Odeh et al., GCN 39097; Ferro et al., GCN 39098; Bochenek et al., GCN 39099; Malesani et al., GCN 39100; Romanov, GCN 39101; Zheng & Filippenko, GCN 39102; Watson et al., GCN 39104; Vinko et al., GCN 39105; Akl et al., GCN 39106; Moskvitin et al., GCN 39107; Calapai, GCN 39109). We observed the optical counterpart fading with a temporal index of ~1.75, consistent with the value reported by Akl et al. (GCN 39106). Select photometry is reported below. Tmid - T0 (days)| Telescope | Filter | Exposure (s) | Mag. | Mag Error --------------------------------------------------------------------------- 0.591 | PROMPT-MO | R | 100x80 | 17.482 | 0.051 1.191 | PROMPT-5 | R | 300 | 18.725 | 0.054 2.114 | PROMPT-5 | R | 10x300 | 19.828 | 0.057 2.566 | PROMPT-MO | R | 150x80 | 20.153 | 0.058 Our images have been calibrated using stars from the APASS catalog. Magnitudes were not corrected for dust extinction. Additional Skynet observations are ongoing. View this GCN Circular online at https://gcn.nasa.gov/circulars/39110. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37118] GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
by GCN Circulars 01 Feb '25

01 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39109 SUBJECT: GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations DATE: 25/02/01 00:21:27 GMT FROM: Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, Messina, Italy <giovannicalapai(a)tiscali.it> Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, (Messina) Italy Member of: GRB/UAI Gamma Ray Burst Section of Unione Astrofili Italiani. Report: We observed the field of GRB 250129A (Swift trigger=1285812, Page et al., GCN 39066) with the 11 inches Schmidt-Cassegrain (Celestron 11) telescope F/D=6,3. The observations were started at 2025-01-31 01:00 UT (approximately 44.25 hours after burst) stacking a set of unfiltered CCD image. The observations were carried out with clear skies and fair visibility conditions. The OT was detected at the following position: RA (J2000.0) 13h 14m 42.38s Decl. (J2000.0) +05° 01' 50.8" Photometry was obtained using nearby PanSTARRS stars as follows: Observation Mid-Time T-T0 (hr) Exposure Filter Mag. Err. 2025-01-31 02:34:24 UT 45.82 105x60s CR 20.14 +/-0.30 Magnitude was calibrated with the nearby PanSTARRS stars converted using Lupton (2005) equations. No correction for galactic dust extinction was applied. Our observations are consistent with other already reported Lipunov et al. (GCN 39070), Gompertz et al. (GCN 39072), Malesani et al. (GCN 39073), Izzo et al. (GCN 39074), Lipunov et al. (GCN 39075), 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), Odeh et al. (GCN 39097), Ferro et al. (GCN 39098), Bochenek et al. (GCN 39099), Malesani et al. (GCN 39100), Romanov (GCN 39101), Zheng et al. (GCN 39102), Watson et al. (GCN 39104), Vinko et al. (GCN 39105), Akl et al. (GCN 39106), Moskvitin et al. (GCN 39107). The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39109. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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