GRB 210707A
GCN Circular 30414
Subject
GRB 210707A: A long GRB detected by INTEGRAL
Date
2021-07-08T06:19:43Z (4 years ago)
From
Sandro Mereghetti at IASF-Milano/INAF <sandro.mereghetti@inaf.it>
S.Mereghetti (INAF, IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno,
E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC,
Versoix) and J.Borkowski (CAMK, Torun) report:
a gamma ray burst lasting about 50 s has been detected by IBAS in the
IBIS/ISGRI data at 22:25:05 UT of 2021 July 7. The corresponding WEAK
type Alert Packet with the burst position was distributed in real time
(Alert n. 9296).
The refined coordinates (J2000) are:
R.A.= 192.5460 deg
DEC.= -63.2763 deg
with an uncertainty of 3 arcmin (90% c.l.).
The burst had a peak flux of 0.2 ph/cm2/s (20-200 keV, 1-s integration
time) and a fluence in the same energy range of about 5e-7 erg/cmq.
A plot of the light curve is posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html
GCN Circular 30420
Subject
Fermi GBM Sub-Threshold Detection of GRB 210707A
Date
2021-07-08T16:49:47Z (4 years ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
C. Fletcher (USRA) reports on behalf of the Fermi-GBM Team:
INTEGRAL/IBAS detected GRB 210707A at 22:25:05 UT (GCN 30414). There was no
Fermi-GBM onboard trigger around the event.
An automated, blind search for short gamma-ray bursts below the onboard
triggering threshold in Fermi-GBM identified no counterparts.
The GBM targeted search [1], the most sensitive, coherent search for
GRB-like signals identified a transient most significantly on the 8.192 s
timescale, with a false alarm rate of 6.4e-06 Hz and a location consistent with
the INTEGRAL/IBAS event, using the standard search protocol with a S/N of 15.
The GBM targeted search event was found with the highest
significance with a "norm" spectrum (Band function with
Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB.
[1] Goldstein et al. 2019 arXiv:1903.12597