[vsnet-grb-info 28180] GRB 210619B: SRG/ART-XC detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30283
SUBJECT: GRB 210619B: SRG/ART-XC detection
DATE:    21/06/21 06:37:17 GMT
FROM:    Sergey Molkov at Space Research Inst., Moscow  <molkov at iki.rssi.ru>

V. Levin, S. Molkov, I. Mereminskiy, А. Lutovinov, A. Semena
and E. Filippova (IKI RAN)
report on behalf of SRG/ART-XC team:


At 23:59:21 UT on 19/06/2021 the Mikhail Pavlinsky ART-XC telescope on 
board the Spektr-RG observatory
detected a short peak in the 40-120 keV count rate. This peak is 
associated with the luminous GRB210619B
registered simultaneously by other space-bourne missions (Swift/BAT 
(D'Avanzo et al. 2021, GCN 30261),
GECAM (Zhao et al. 2021, GCN 30264), Fermi-LAT (Axelsson et al. 2021, 
GCN 30270), Konus-Wind
(Svinkin et al. 2021, GCN 30276), Fermi/GBM (Poolakkil and Meegan 2021, 
GCN  30279)).

The burst light curve is similar to what observed by other telescopes, 
with a prominent initial peak
(that lasted for 6 s and having a typical fast rise exponential decay 
form) and several
consecutive peaks, roughly coincident with ones detected by Konus-Wind.

The angle between telescope axis and the burst was 45 degrees, which 
means that the burst emission
had penetrated through the side shield of ART-XC detectors. This 
significantly complicates the spectral analysis,
which will be presented elsewhere.

The Mikhail Pavlisky ART-XC is an X-ray telescope working in the  hard 
X-ray band (above 4 keV) in the
Langrangian point L2. It could observe brightest GRBs through its 
side/back shielding, providing an
additional leverage for the  IPN-like triangulation of such events.