{
  "bibcode": "2020GCN.27668....1M",
  "body": "S. Mereghetti (INAF, IASF-Milano), V. Savchenko (ISDC, Versoix), D. Gotz\n(CEA, Saclay), L. Ducci, C. Ferrigno, E. Bozzo (ISDC, Versoix), J.Borkowski\n(CAMK, Torun) and A. Bazzano (INAF, IAPS-Roma) report\n\n\nA bright short burst has been detected by IBAS in the IBIS/ISGRI data at\n14:34:24 UT of April 28 (Alert Packet n. 8611), and promptly identified as\noriginating from the currently active SGR 1935+2154 (GCN #27667, #27666,\n#27665, #27664, #27663, #27662, #27661, #27659, #27657, #27631, ATel\n#13682, #13679, #13678, #13675).  Note that the above time is not corrected\nfor the light-travel but it is consistent with  the one of the radio  burst\nfrom the same source reported in ATel #13681, #13684.\n\nThe burst was at an off-axis angle of 8.1 degrees, in the field of view of\nthe IBIS and SPI instruments, but outside those of JEM-X and OMC.\n\nA preliminary analysis indicates that the burst had a duration of about 0.3\ns,  a fluence of 3.9+/-0.2e-7 erg/cm2 in the 25-80 keV range  and a peak flux of\n1.2+/-0.1 e-6 erg/cm2/s on 10 ms timescale.\n\nThe burst  was also marginally detected in the SPI-ACS  with S/N=4.65 on a\n 0.65s time scale. The ACS observation independently gives a  FAP at the\nlevel of 0.0019 (2.9 sigma).\n\nWe note that another weaker burst from SGR 1935+2154, lasting about 0.1 s\nwas  detected  by IBAS at 09:51:05 UT of April 28 (Weak Alert Packet n.\n8610).\n\nISGRI and SPI-ACS lightcurves of the bright event are available at:\n\nhttps://www.isdc.unige.ch/integral/ibas/cgi-bin/ibas_acs_web.cgi/?trigger=2020-04-28T14-34-23.4100-00000-00000-0\n\n[GCN OPS NOTE(29apr20): Per author's request, the fluence in the 3rd paragraph\nwas changed from \"3.9+/-0.2e-5\" to \"3.9+/-0.2e-7 erg/cm2\" (ie the value\nwent down by 100x and units were added.  A thank-you to V.Palshin\nfor pointing out the typo.]",
  "circularId": 27668,
  "createdOn": 1588152638000,
  "email": "sandro.mereghetti@inaf.it",
  "subject": "SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst",
  "submitter": "Sandro Mereghetti at IASF-Milano/INAF  <sandro.mereghetti@inaf.it>",
  "eventId": "SGR 1935+2154"
}