Gamma-ray Burst 241009A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN Circular #37749
  SVOM/ECLAIRs Commissioning Team: Jean-Luc Atteia, Laurent Bouchet, Sebastie= n Guillot, Juliette Alaux (IRAP), St=C3=A9phane Schanne, Fr=C3=A9d=C3=A9ric= Chateau, Nicolas Dagoneau, Herv=C3=A9 Le Provost (CEA), Wenjin Xie (NAOC),= Floriane Cangemi (APC), Tais Maiolino (LUPM), Karine Mercier, Marie-Claire = Charmeau, Stefano Crepaldi (CNES)
  SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I= HEP), St=C3=A9phane Basa (LAM), Olivier Godet (IRAP), Arnaud Claret (CEA), = Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC), A= ndrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril Lacha= ud (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/ECLAIRs telescope triggered and lo= cated GRB 241009A (sb24100915) at 2024-10-09T19:17:29 UT (Tb).
  The following trigger information was received on the ground with low-laten= cy by the SVOM VHF Alert Network. The burst was detected by both the on-board Count-Rate Trigger (CRT) and Im= age Trigger (IMT) and 12 Alerts were received. The detection with the best = signal-to-noise ratio of 15.3 sigma is obtained by CRT in the 8-50 keV ener= gy band over a time window of 10.24 s starting at Tb.
  This is a clear long duration GRB.
  The median location of the event on all 12 Alerts is RA, Dec =3D 325.11, -3= 5.63 (J2000). The statistical uncertainty on this position is 5.6 arcminutes, to which we= recommend adding 10 arcminutes of systematic uncertainty in quadrature.
  The SVOM satellite did not slew onto this burst.
  The Space Variable Objects Monitor (SVOM) is a China-France joint mission l= ed by the Chinese National Space Administration (CNSA), French Space Agency= (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to o= bserving gamma-ray bursts and other transient phenomena in the energetic un= iverse. ECLAIRs was developed jointly by APC, CEA, CNES, and IRAP.
  The SVOM point of contact for this burst is: olivier.godet AT irap.omp.eu
• GCN Circular #37752
  P. A. Evans (U. Leicester) reports on behalf of the Swift team:
  Swift has initiated a ToO observation of the SVOM/ECLAIRs GRB 241009A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021722
  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 #37772
  M. A. Williams (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB) 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 241009A, collecting 2.1 ks of Photon Counting (PC) mode data between T0+14.7 ks and T0+106.0 ks.
  Seven uncatalogued X-ray sources are detected, of which one ("Source 1") is believed to be the afterglow. Using 433 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 325.00866, -35.65944 which is equivalent to:

  RA (J2000): 21h 40m 02.08s
  Dec(J2000): -35d 39' 34.0"
  

  with an uncertainty of 4.2 arcsec (radius, 90% confidence). This position is 6.3 arcmin from the SVOM/ECLAIRs position. The source has faded from a count rate of 0.0441 [+0.013, -0.011] ct s^-1 at T0+14.9 ks to an upper limit of 0.0132 ct s^-1 at T0+100.9 ks.
  The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021722. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021722.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #37773
  T. Hussenot-Desenonges (IJCLAB), Y. Rajabov (UBAI), A. Tanasan (NARIT), I. = Abdi (AUS), R.Strasbaugh (EIU), M.Lamoureux (UCLouvain), S. Antier (OCA), S= . Karpov (FZU), M. Coughlin (UMN), C. Andrade (UMN), I. Tosta e Melo (UniCT= -DFA), P. Hello, N. Leroy (IJCLAB), P-A Duverne (APC), T. Pradier (Unistra/= IPHC), N. Guessoum (AUS), A. Klotz (IRAP/OMP), C. Limonta, M .Boer (OCA), M= . Masek, M. Prouza (FZU), D.Turpin (CEA-Saclay/Irfu), M. Freeberg, D. St-Ge= lais (KNC) on behalf of the GRANDMA collaboration.
  We observed the field of GRB 241009A, detected by SVOM/ECLAIRs (GCN 37749) = with the GRANDMA network and its citizen science project Kilonova-catcher (= KNC). Our observations started with TAROT-Reunion (TRE), 36 min after the t= rigger.
  We did not detect any uncatalogued optical sources in the error region of S= VOM/ECLAIRs, with the following 5-sigma upperlimits on the field:

  | Tstart (UTC)  | Telescope | Exposure | Filter | U.L. |
  =09 =09 =09 =09
  | 2024-10-09T19:53:31 | TAROT-TRE | 32x60s | Clear (G) | 18.7 (Vega) |
  | 2024-10-09T21:13:08 | FRAM-CTA-N | 17x120s | R | 18.4 (Vega) |
  | 2024-10-09T22:25:02 | KNC-HakosRC360 | 19x180s | sdssr | 19.8 (AB) |
  | 2024-10-09T23:39:34 | FRAM-Auger | 15x120s | R | 18.2 (Vega) |
  | 2024-10-10T02:16:21 | KNC-Obs. Laurier | 41x60s | R | 19.1 (Vega) |
  

  In particular, within these upperlimits, we do not detect any optical count= erpart of the Swift-XRT afterglow position candidate (RA 21h 40m 02.08s DEC= -35=C2=B0 39=E2=80=B2 34.0=E2=80=B3) (GCN 37772).
  Images obtained in Johnson Cousin filters were calibrated using the Gaia DR= 3 Synphot catalog. Images obtained with Sloan filters were calibrated using= the SkyMapper DR4 catalog. The unfiltered image taken by TAROT-TRE was cal= ibrated as a Gaia G image using the Gaia eDR3 catalogue.
  All the data have been reduced by a single data processing pipeline, STDPip= e (Karpov et al., 2022). We use the SkyPortal application (skyportal.io) to= monitor our observational campaign.
  We thank the SVOM collaboration for useful communication.
  GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted = to the observation of transients in the context of multi-messenger astrophy= sics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the ci= tizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
• GCN Circular #37786
  D. Turpin (CEA/Irfu), J. T. Palmerio (CEA/Irfu, GEPI/Obs. de Paris), A. Sac= cardi (GEPI/Obs. de Paris, CEA/Irfu), S. Vergani (GEPI/Obs. de Paris), S. B= asa (OSU Pytheas, LAM), E. Le Floc'h (CEA Paris-Saclay, DAp/AIM) on behalf = of a larger collaboration.
  We observed the field of GRB 241009A detected by SVOM/ECLAIRs (Dagoneau et = al., GCN 37749) with the LCO 1m telescope at the Cerro Tololo Inter-America= n Observatory equipped with the Sinistro instrument. Our observation starte= d at 2024-10-10 03:53:09 (T - TGRB =3D 8.6 h) with 4 x 180s exposure using = the sdss-r filter.
  We did not detect any uncatalogued optical source in the error region of SV= OM/ECLAIRs (Dagoneau et al., GCN 37749) and at the position of the Swift/XR= T afterglow source (Williams et al., GCN 37772). We derived the following u= pper limit (5 sigma, AB system) calibrated with the SkyMapper DR4 catalog a= nd not corrected from the galactic extinction:
  r > 20.9 (AB)
  This project has received funding from the European Union=E2=80=99s Horizon= 2020 research and innovation programme under grant agreement No 101004719.