GRB240926A

This page lists all entries on GRB240926A in GRBweb

Summary IPN GCN 37616 GCN 37639 GCN 37701

Summary table
Variable Value Source
T0 11:42:44 UTC GCN_circulars,IPN Triangulation
ra 240.3625° IPN
decl 45.3667° IPN
pos_error 1.60e+00° IPN
GBM_located False
mjd 60579.48800925926 GCN_circulars,IPN Triangulation
IPN table
GRB_name GRB240926A
ra 240.3625°
decl 45.3667°
pos_error 1.60e+00°
GCN 37616 table
GRB_name GRB240926A
GCN_number 37616
Detection_method Other
ra 241.9200°
decl 40.3100°
Circular_text TITLE: GCN CIRCULAR NUMBER: 37616 SUBJECT: GRB 240926A: SVOM/GRM observation DATE: 24/09/27 07:55:33 GMT FROM: wenlongzhang2018@163.com SVOM/GRM team: Wen-Long Zhang, Yue Huang, Yan-Ting Zhang, Jia-Cong Liu, Yong-Wei Dong, Jiang-Tao Liu, Shi-Jie Zheng, Jian-Chao Sun, Wen-Jun Tan, Jiang He, Chen-Wei Wang, Min Gao, Hao-Xuan Guo, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming Song, You-Li Tuo, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Ping Wang, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Lin Xiong, Jian-Ying Ye, Yi-Tao Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zhang, Shuang-Nan Zhang, Shu-Min Zhao, Xiao-Yun Zhao, Chao Zheng (IHEP), Maria-Grazia Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Tais Maiolino (LUPM), Frédéric Piron (LUPM), Stéphane Schanne (CEA), Jingwei Wang (IAP) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), JeanLuc Attéia (IRAP), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (UNLV) report on behalf of the SVOM team: During the commissioning phase, the SVOM/GRM was triggered in-flight by GRB 240926A (SVOM trigger reference: sb24092601) at 2024-09-26T11:42:45.000 UT (T0). The real-time alert data and light curves of SVOM/GRM were downlinked to the ground through the VHF system with low latency. The light curves show that this burst consists of multiple pulses with a T90 of 55.54 s -0.39/+0.48 s. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb240926A.png The SVOM/GRM on-ground localization of this burst is (J2000): RA: 241.92 deg DEC: 40.31 deg Error: 3.78 deg (1 sigma, statistical only) We caution that the calibration of SVOM/GRM is undergoing and this localization is subject to systematic errors. The localization may be improved in the refined analysis. At the time of the burst ECLAIRs was not in operational mode. 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: Wen-Long Zhang (IHEP)(zhangwl@ihep.ac.cn)
GCN 37639 table
GRB_name GRB240926A
GCN_number 37639
Detection_method IPN Triangulation
t_trigger 11:42:44 UTC
ra 240.3610°
decl 45.3640°
Circular_text TITLE: GCN CIRCULAR NUMBER: 37639 SUBJECT: IPN triangulation of GRB 240926A DATE: 24/09/30 15:36:50 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. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, E. Burns, on behalf of the IPN, E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, 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 long-duration GRB 240926A (SVOM-GRM detection: Zhang et al., GCN 37616) was detected by SVOM (GRM), Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND) at about 42164 s UT (11:42:44). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 240.361 (16h 01m 27s) +45.364 (+45d 21' 52") Corners: 241.263 (16h 05m 03s) +45.816 (+45d 48' 59") 241.214 (16h 04m 51s) +45.898 (+45d 53' 53") 239.475 (15h 57m 54s) +44.903 (+44d 54' 12") 239.526 (15h 58m 06s) +44.822 (+44d 49' 21") --------------------------------------------- The error box area is 483 sq. arcmin, and its maximum dimension is 1.6 deg (the minimum one is 5.1 arcmin). The Sun distance was 68 deg. The IPN localization is consistent with, but reduces the area of, the SVOM-GRM localization (GCN 37616). This localization may be improved. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB240926_T42164/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 37701 table
GRB_name GRB240926A
GCN_number 37701
Detection_method Konus-Wind Det
t_trigger 11:42:44.378 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 37701 SUBJECT: Konus-Wind detection of GRB 240926A DATE: 24/10/03 18:09:39 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 240926A (SVOM/GRM observation: Zhang et al., GCN 37616; IPN triangulation: Kozyrev et al., GCN 37639) triggered Konus-Wind (KW) at T0=42164.378 s UT (11:42:44.378). The burst light curve shows a multi-peaked structure, which starts at ~T0-16 s, peaks at ~T0+31 s, and has a total duration of ~75 s. The emission is seen up to ~3 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB240926_T42164/ As observed by Konus-Wind, the burst had a fluence of (5.89 ± 0.59)x10^-5 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 31.424 s, of (9.03 ± 0.85)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+62.720 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 = -1.65 (-0.05,+0.06), the high energy photon index beta = -2.60 (-0.55,+0.21), the peak energy Ep = 118 (-11,+12) keV, chi2 = 119/97 dof. The spectrum near the peak count rate (measured from T0+31.232 s to T0+38.144 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.55(-0.07,+0.07) and Ep = 151(-14,+17) keV (chi2 = 98/80 dof). Fitting this spectrum by a Band function yields the same values of alpha and Ep, and an upper limit on the high energy photon index beta of -2.6 (chi2 = 98/79 dof). All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.