GRB250308A

This page lists all entries on GRB250308A in GRBweb

Summary IPN GCN 39632 GCN 39636 GCN 39653 GCN 39676 GCN 39720

Summary table
Variable Value Source
T0 18:06:31 UTC GCN_circulars,IPN Triangulation
ra 160.7625° IPN
decl 23.7333° IPN
pos_error 3.00e+00° IPN
GBM_located False
mjd 60742.754525462966 GCN_circulars,IPN Triangulation
IPN table
GRB_name GRB250308A
ra 160.7625°
decl 23.7333°
pos_error 3.00e+00°
GCN 39632 table
GRB_name GRB250308A
GCN_number 39632
Detection_method Konus-Wind Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 39632 SUBJECT: GRB 250308A: SVOM/GRM observation of a bright short burst DATE: 25/03/09 12:40:35 GMT FROM: Chenwei Wang at IHEP SVOM/GRM team: Chen-Wei Wang, Zheng-Hang Yu, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Nicolas Dagoneau (CEA), Maria-Grazia Bernardini (INAF-OAB), Jean-Luc Atteia (IRAP), Frédéric Piron (LUPM) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by GRB 250308A (SVOM trigger reference: sb25030804) at 2025-03-08T18:06:30.9 (T0), which is also detected by CALTE/GBM (TRIGGER ID: 1425492335) and Konus-Wind. 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 1.9 +0.9/-0.8 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250308A.png 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@ihep.ac.cn)
GCN 39636 table
GRB_name GRB250308A
GCN_number 39636
Detection_method Other
ra 170.9000°
decl 25.6000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39636 SUBJECT: GRB 250308A: SVOM/GRM detection of QPO in the tail emission DATE: 25/03/09 16:00:23 GMT FROM: Chenwei Wang at IHEP SVOM/GRM team: Chen-Wei Wang, Wen-Jun Tan, Zheng-Hang Yu, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Nicolas Dagoneau (CEA), Maria-Grazia Bernardini (INAF-OAB), Jean-Luc Atteia (IRAP), Frédéric Piron (LUPM) Report on behalf of the SVOM team: The bright short burst, GRB 250308A (GCN #39632), consists of a narrow spike followed by a short tail emission (from T0-0.15 to T0+0.15 s), which shows a feature of QPO, with a center frequency at approximately 31 Hz. The on-ground localization of this burst is (J2000): RA: 170.9 deg DEC: 25.6 deg Error: 5.2 deg (1sigma, statistical only) We caution that the calibration of SVOM/GRM is undergoing and this localization is subject to systematic errors. With this localization, the time-averaged spectrum from T0-0.3 to T0+0.2 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.28 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 452 +/- 56 keV. The event fluence (10-1000 keV) in this time interval is (4.9 +/- 0.2)E-06 erg/cm^2. The feature of QPO in the tail emission and the spectrum parameters are consistent with the scenario of magnetar giant flare. Follow-up observations are strongly encouraged. We note that these results are preliminary. Refined analysis will be reported later. 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@ihep.ac.cn)
GCN 39653 table
GRB_name GRB250308A
GCN_number 39653
Detection_method IPN Triangulation
t_trigger 18:06:31 UTC
ra 160.7610°
decl 23.7410°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39653 SUBJECT: IPN triangulation of GRB 250308A (short) DATE: 25/03/10 16:02:51 GMT FROM: Dmitry Svinkin at Ioffe Institute A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team, D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, Y. Zhang, C. Wang, S. Xiong, J. Wei, and B. Cordier on behalf of the SVOM-GRM team, S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, E. Burns on behalf of the IPN, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The short-duration GRB 250308A (SVOM-GRM detection: Wang et al., GCN 39632, 39636) was detected by SVOM (GRM), Konus-Wind, Swift (BAT), CALET (GBM), and Mars-Odyssey (HEND) at about 65191 s UT (18:06:31). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 160.761 (10h 43m 03s) +23.741 (+23d 44' 26") Corners: 160.858 (10h 43m 26s) +24.405 (+24d 24' 18") 160.981 (10h 43m 55s) +24.338 (+24d 20' 15") 160.655 (10h 42m 37s) +23.074 (+23d 04' 27") 160.536 (10h 42m 09s) +23.145 (+23d 08' 43") --------------------------------------------- The error box area is 578 sq. arcmin, and its maximum dimension is 1.3 deg (the minimum one is 7.4 arcmin). The Sun distance was 159 deg. This localization may be improved. The distance between the center of SVOM (GRM) localization (GCN 39636) and the IPN box center is 9.4 deg. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250308_T65194/IPN/ The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
GCN 39676 table
GRB_name GRB250308A
GCN_number 39676
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39676 SUBJECT: GRB 250308A: Swift/BAT-GUANO localization skymap of a short burst DATE: 25/03/11 20:10:54 GMT FROM: Samuele Ronchini at PSU 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 250308A onboard (T0: 2025-03-08T18:06:30.72 UTC, CALET/GBM trig 1425492335 GCN 39663, SVOM/GRM GCN 39632) 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 32.5 in a 0.256 s analysis time bin, starting at T0 - 0.064 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 2,693 deg2 and the 50% credible area is 785 deg2. The integrated probability inside the coded field of view is <1%. The NITRATES skymap is consistent with the SVOM/GRM (GCN 39636) and IPN (GCN 39653) localizations. A plot of the probability skymap can be viewed here: [skymap_plot](https://guano.swift.psu.edu/trigger_report?id=763150025/#:~:text=Probability%20Skymap) The probability skymap file can be downloaded from the link here [skymap_fits_file](https://guano.swift.psu.edu/files/763150025/0_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=763150025 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/
GCN 39720 table
GRB_name GRB250308A
GCN_number 39720
Detection_method Konus-Wind Det
t_trigger 18:06:34.997 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 39720 SUBJECT: Konus-Wind detection of GRB 250308A DATE: 25/03/14 15:54:17 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The short-duration GRB 250308A (SVOM-GRM detection: Wang et al., GCNs 39632, 39636; IPN triangulation: Kozyrev et al., GCN 39653; CALET-GBM detection: Kawakubo et al., GCN 39663; Swift-BAT/GUANO detection: DeLaunay et al., GCN 39676) triggered Konus-Wind at T0=65194.997 s UT (18:06:34.997). The burst light curve shows a multipeaked structure which starts at ~T0-40 ms and has a total duration of ~0.4 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250308_T65194/ As observed by Konus-Wind, the burst had a fluence of 8.23(-0.52,+0.54)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0-6 ms, of 5.24(-0.69,+0.70)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.41(-0.12,+0.13) and Ep = 1176(-109,+125) keV (chi2 = 60/52 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.9 (chi2 = 60/51 dof). All the quoted errors are at the 68% confidence level. All the quoted values are preliminary.