[vsnet-grb-info 21179] INTEGRAL detections of the prompt gamma-ray emission of GRB 180914B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23278
SUBJECT: INTEGRAL detections of the prompt gamma-ray emission of GRB 180914B
DATE:    18/09/28 11:05:12 GMT
FROM:    Volodymyr Savchenko at ISDC,U of Geneve  <savchenk at in2p3.fr>

J. Rodi, A. Bazzano, P. Ubertini, L. Natalucci (IAPS-Roma)
C. Ferrigno, V. Savchenko (ISDC, University of Geneva, CH)
E. Kuulkers (ESTEC/ESA, The Netherlands)

We have analyzed the public INTEGRAL data of IBIS/PICsIT (200 - 2600 keV)
and SPI-ACS(>75 keV) in coincidence with the long, bright GRB 180914B,
which was initially reported by AGILE/MCAL (GCN 23226), AGILE/GRID (GCN
23231),
and Fermi/LAT(GCN 23232). The INTEGRAL orientation was 98.4 degrees from
the GRB location and implies a near optimal response for SPI-ACS and
a suppressed response for PICsIT (Savchenko et al. 2017, A&A 603, A46).

The GRB was clearly detected in SPI-ACS until about T0+250s
(T0=2018-09-14 18:23:02.22) and shows 8 flaring events, of which 7 show
large variability detected down to the 50 ms time-resolution of the
detector. 
It was also detected in PICsIT until approximately T0+130s, of which 5
flaring
events are clearly seen.  Because of the unfavorable viewing angle for
PICsIT,
the burst is predominately seen above 460 keV with significant
emission up to 1.2 MeV.

The SPI-ACS light curve can be found at:

https://www.isdc.unige.ch/integral/ibas/cgi-bin/ibas_acs_web.cgi/?trigger=2018-09-14T18-23-01.00-00000-00000-0