Gamma-ray Burst 240914A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #37495
  FROM: Jean-Luc Atteia at IRAP
  SVOM/ECLAIRs commissioning team: Alexis Coleiro (APC), St=C3=A9phane Schann= e, Fr=C3=A9d=C3=A9ric Chateau, Nicolas Dagoneau, Herv=C3=A9 Le Provost (CEA= ), Olivier Godet, Laurent Bouchet, Sebastien Guillot, Juliette Alaux (IRAP)= , Tais Maiolino (LUPM), Karine Mercier, Marie-Claire Charmeau, Stefano Crep= aldi (CNES)
  SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I= HEP), St=C3=A9phane Basa (LAM), Jean-Luc Atteia (IRAP), Arnaud Claret (CEA)= , Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC),= Andrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril Lac= haud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Par= is), 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/ECLAIRs telescope triggered and lo= cated GRB 240914A (sb24091403) an intermediate duration GRB or SGR at 2024-= 09-14T01:40:03.9 UT (T0).
  The following information was received on the ground with by the SVOM VHF A= lert Network:
  The burst was detected by the Count-Rate Trigger (CRT) onboard ECLAIRs. The= signal to noise ratio in the reconstructed image is 10.5 in the 8-50 keV e= nergy band during a time window of 5.12 s starting at T0. The transient loc= ation is RA, DEC =3D 54.281, -35.027 (J2000). The statistical uncertainty o= n this position is 10.3 arcminutes, to which we recommend to add 10 arcminu= tes of systematic uncertainty in quadrature during the commissioning phase.
  SVOM did not slew to the burst since automated slewing was not enabled.
  We note that this position is about 10 arcminutes from NGC 1380.
  The Space Variable Objects Monitor (SVOM) is a China-France joint mission l= ed by the Chinese National Space Administration (CNSA, China), French Space= Agency (CNES, France) and the Chinese Academy of Sciences (CAS, China), wh= ich is dedicated to observing gamma-ray bursts and other transient phenomen= a in the energetic universe. ECLAIRs was developed jointly by APC, CEA, CNE= S and IRAP.
  The SVOM point of contact for this burst is J-L Atteia: jean-luc.atteia@irap.omp.eu
• GCN Circular #37498
  L. Asquini, M. Landoni, P. D'Avanzo, S. Campana (INAF-Brera), C. Farias (ESO/ La Silla) report:
  We observed the field of GRB 240914A (SVOM team, GCN Circ. 37495) with the = ESO-NTT telescope equipped with EFOSC2 starting at 2024-09 14T08:38:49 UT (= i.e. about 7 hours after the burst T0), during an on-site test run for the = scheduler of the incoming SOXS instrument. Observations have been carried out in imaging mode with the Gunn r filter, = pointing to the NGC 1380 galaxy position with a 4=E2=80=99 x 4=E2=80=99 fie= ld of view.
  Visual inspection with archival optical images of NGC 1380 from the Legacy Survey shows no clear evidence for new transients.
  From preliminary photometry, we estimate a 3sigma limit of r ~ 22.5 mag (AB), for a region in the outskirts of the NGC 1380 galaxy.
  Further observations and analysis are ongoing.
• GCN Circular #37502
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a ToO observation of the SVOM/ECLAIRs GRB 240914A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021716
  Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the SVOM/ECLAIRs event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration.
  Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
  This circular is an official product of the Swift-XRT team.
• GCN Circular #37504
  SVOM/GRM team: Chen-Wei Wang, Yong-Wei Dong, Jiang-Tao Liu, Shi-Jie Zheng, = Jian-Chao Sun, Wen-Jun Tan, Jiang He, Min Gao, Hao-Xuan Guo, Yue Huang, 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 Zha= ng, Li Zhang, Peng Zhang, Shuang-Nan Zhang, Wen-Long Zhang, Yan-Ting Zhang,= Shu-Min Zhao, Xiao-Yun Zhao, Chao Zheng (IHEP), Maria-Grazia Bernardini (L= UPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Tais Maiolino (LU= PM), Fr=C3=A9d=C3=A9ric Piron (LUPM), St=C3=A9phane Schanne (CEA), Jingwei = Wang (IAP)
  SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I= HEP), St=C3=A9phane Basa (LAM), JeanLuc Att=C3=A9ia (IRAP), Arnaud Claret (= CEA), Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NA= OC), Andrea Goldwurm (APC), Diego G=C3=B6tz (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 both in-flight a= nd on-ground by a weak GRB 240914A (SVOM trigger reference: sb24091403) at = 2024-09-14T01:40:03.9 UT (T0), which was also observed and located by SVOM/= ECLAIRs=EF=BC=88Alexis Coleiro et al., GCN 37495=EF=BC=89.
  The real-time alert data and light curves of SVOM/GRM were downlinked to th= e ground through the VHF system with low latency. With the event-by-event d= ata downloaded through the X-band ground station, the GRM light curve shows= that this burst consists of a single pulse with a T90 of 4.6 s +3.1/-4.4 s= .
  The GRM light curve can be found here: https://www.bursthub.cn/admin/static/svgrb240914A.png
  The Space Variable Objects Monitor (SVOM) is a China-France joint mission l= ed by the Chinese National Space Administration (CNSA, China), National Cen= ter for Space Studies (CNES, France) and the Chinese Academy of Sciences (C= AS, China), which is dedicated to observing gamma-ray bursts and other tran= sient phenomena in the energetic universe. GRM is developed by the Institut= e of High Energy Physics (IHEP) of CAS.
  The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang@ih= ep.ac.cn)
  
• GCN Circular #37508
  S. Dichiara (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , J.A. Kennea (PSU), D.N. Burrows (PSU) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
  Swift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected burst GRB 240914A, collecting 1.9 ks of Photon Counting (PC) mode data between T0+36.3 ks and T0+42.4 ks.
  No uncatalogued X-ray sources have been detected. The 3-sigma upper limit in the field ranges from ~0.005 to ~0.006 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.9e-13 to 2.3e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
  Three previously-catalogued X-ray sources have been detected, however their status as catalogued objects makes them unlikely to be the afterglow.
  The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021716.
  This circular is an official product of the Swift-XRT team.