{
  "submittedHow": "web",
  "eventId": "GRB 260509A",
  "circularId": 44504,
  "submitter": "Diego Gotz at CEA <diego.gotz@cea.fr>",
  "format": "text/plain",
  "createdOn": 1778365584706,
  "body": "GRB 260509A: SVOM detection of a burst\n\nD. Götz (CEA/Irfu), A. Saccardi (CEA/Irfu), H. Goto (RIKEN), F. Lacreu (IAP), D. Adrien (CEA/Irfu), report on behalf of the SVOM mission team:\n\nAt 2026-05-09T21:51:09 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260509A (SVOM burst-id sb26050905).\n\nThe following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.\n\nThe burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 18 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 18.00 in the [5-20] keV energy band over a time window of 20.40 seconds starting at 2026-05-09T21:51:03.\n\nThe localization of the best alert is R.A., Dec. 176.8870, 0.2095 degrees:\nR.A. (J2000) = 11h47m32.9s\nDec. (J2000) = 0d12m34.2s\n with a 90% confidence level (C.L.) radius of 4.72 arcmin (including systematic error of 2 arcmin added in quadrature).\n\nWe note the presence of a high proper motion star G 10-49 at a distance of 4.48 arcmin from the ECLAIRs position.\n\nThe SVOM/ECLAIRs light curve showed a single peak structure with a T90 duration of about 14.7 +/-0.6 s.\n\nThis burst was also detected by SVOM/GRM with a significance of 6.40.\nThe SVOM/GRM light curve showed a double peak structure with a T90 duration of about 18 (-6/+10) s.\n\nSVOM slewed to the burst.\n\nMXT and VT began observing the field after the slew. The analysis of the data will be published in  future circulars.\n\nThe Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE.\n\nThe Burst Advocate (BA) on shift for this alert is Dylan Adrien: dylan.adrien@cea.fr.\nPlease contact the BA by email if you require additional information.\n",
  "subject": "GRB 260509A: SVOM detection of a burst"
}