GRB250222A

This page lists all entries on GRB250222A in GRBweb

Summary GCN 39454 GCN 39588 GCN 39590

Summary table
Variable Value Source
T0 14:24:19 UTC GCN_circulars,IPN Triangulation
ra 359.3360° GCN_circulars,IPN Triangulation
decl 0.9460° GCN_circulars,IPN Triangulation
GBM_located False
mjd 60728.60021990741 GCN_circulars,IPN Triangulation
GCN 39454 table
GRB_name GRB250222A
GCN_number 39454
Detection_method Other
ra 284.2000°
decl -61.0000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39454 SUBJECT: GRB 250222A: SVOM/GRM observation of a burst DATE: 25/02/24 13:15:04 GMT FROM: Chenwei Wang at IHEP SVOM/GRM team: Chen-Wei Wang, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Frédéric Piron (LUPM), Nicolas Dagoneau (CEA), Maria-Grazia Bernardini (INAF-OAB), Jean-Luc Atteia, Sébastien Guillot (IRAP) report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by a long burst GRB 250222A (SVOM trigger reference: sb25022201) at 2025-02-22T14:24:26.100 UTC (T0). With the event-by-event data downloaded through the X-band ground station, the GRM light curve of 15 to 600 keV shows that this burst consists of multi-pulses with a T90 of 4.3 +0.6/-0.5 s. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250222A.png The SVOM/GRM on-ground localization of this burst is (J2000): RA: 284.2 deg DEC: -61.0 deg Error: 1.6 deg (1sigma, statistical only) We caution that the calibration of SVOM/GRM is undergoing and this localization is subject to systematic errors. In addition, this burst was detected by the Count-Rate Trigger onboard ECLAIRs, as an increase in counts over background, but it was not localized by the coded-mask imaging process, which confirms that the burst occurred outside the ECLAIRs field of view. 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 39588 table
GRB_name GRB250222A
GCN_number 39588
Detection_method IPN Triangulation
t_trigger 14:24:19 UTC
ra 359.3360°
decl 0.9460°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39588 SUBJECT: IPN triangulation of GRB 250222A DATE: 25/03/04 12:59:51 GMT FROM: Dmitry Svinkin at Ioffe Institute 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, E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, A. Goldstein, M. S. Briggs, C. Wilson-Hodge, and E. Burns on behalf of the Fermi GBM team, S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, report: The long-duration GRB 250222A (SVOM-GRM detection: Wang et al., GCN 39454) was detected by SVOM (GRM), Konus-Wind, and INTEGRAL (SPI-ACS) at about 51859 s UT (14:24:19). Fermi (GBM) and Swift (BAT) were taking data, but shows no rate increase at the burst time. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 359.336 (23h 57m 21s) +0.946 ( +0d 56' 47") Corners: 335.308 (22h 21m 14s) +25.783 (+25d 47' 00") 352.637 (23h 30m 33s) +12.776 (+12d 46' 35") 6.156 (00h 24m 37s) -19.368 (-19d 22' 04") 2.915 (00h 11m 40s) -9.794 ( -9d 47' 40") --------------------------------------------- The error box area is 38.5 sq. deg, and its maximum dimension is 54 deg (the minimum one is 3 deg). The Sun distance was 25 deg. This localization may be improved. The SVOM (GRM) localization (GCN 39454) is inconsistent with the IPN localization and also with burst non-detection by Fermi (GBM) and Swift (BAT). A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250222_T51862/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 39590 table
GRB_name GRB250222A
GCN_number 39590
Detection_method Konus-Wind Det
t_trigger 14:24:22.905 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 39590 SUBJECT: Konus-Wind detection of GRB 250222A DATE: 25/03/04 13:35:08 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long GRB 250222A (SVOM-GRM detection: Wang et al., GCN 39454; IPN triangulation: Svinkin et al., GCN 39588) triggered Konus-Wind (KW) at T0=51862.905 s UT (14:24:22.905). The burst light curve shows a bright, multi-peaked pulse, with the duration of ~2.5 s, followed by a weaker, decaying emission. The total duration of the burst is ~13 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250222_T51862/ As observed by Konus-Wind, the burst had a fluence of (1.79 ± 0.19)x10^-5 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 0.064 s, of (1.53 ± 0.20)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 15 MeV range by a GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.51 (-0.22,+0.26), the high energy photon index beta = -2.28 (-0.14,+0.11), the peak energy Ep = 173 (-21,+23) keV, chi2 = 98/97 dof. The spectrum near the peak count rate (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 15 MeV range by a GRB (Band) function with the following model parameters: the low-energy photon index alpha = 0.40 (-0.61,+1.09), the high energy photon index beta = -1.97 (-0.13,+0.10), the peak energy Ep = 169 (-39,+46) keV, chi2 = 42/43 dof. All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.