{
  "format": "text/plain",
  "createdOn": 1755873579353,
  "body": "L. Bouchet, J.-L. Atteia , O. Godet, M. Brunet (IRAP), L. P. Xin(NAOC), Z.M. Wang(BNU)\nreport on behalf of the SVOM/ECLAIRs team:\n\nUsing the ECLAIRs event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of GRB 250812A (SVOM burst-id sb25081201), triggered by ECLAIRs onboard SVOM (Xin et al., GCN 41322).\n\nThe burst is faint and the 4-120 keV lightcurve is featureless.   \n\nThe time-averaged spectrum from T0-51 s to T0+3 s (T0 =  2025-08-12T02:46:03  UTC) in the energy range 4-120 keV is relatively well fitted by a powerlaw model with index -1.19+/-0.27. With this model, the fluence in 4-120 keV is about 7.5 (-1.9,+0.6) e-7 erg/cm^2.\n\nAll quoted errors are at the 68% confidence level.\n\nThe spectral index suggests that the Epeak value is above 120 keV.\n\nThe source redshift is found to be z=2.571 (Van Dalen et al., GCN 41347; de Ugarte Postigo et al., GCN 41348). At this redshift, GRB 250812A lies in the region of type II GRBs in the Amati plot for values of Epeak ≤ 200 keV. \n\nWe note that the calibration of SVOM/ECLAIRs is ongoing thus these results are preliminary. \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. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC.\n\nThe SVOM/ECLAIRs point of contact for this GCN circular is: Laurent Bouchet (laurent.bouchet@irap.omp.eu).\n",
  "submittedHow": "web",
  "submitter": "SVOM_group <svomgroup@bao.ac.cn>",
  "eventId": "GRB 250812A",
  "bibcode": "2025GCN.41495....1B",
  "circularId": 41495,
  "subject": "GRB 250812A: SVOM/ECLAIRs refined analysis"
}