GRB 220702B

A. Suresh (IITB), R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. 
Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya 
(Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) 
report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 220702B which was 
also detected by Fermi-GBM (Fermi GBM Team, GCN 32324
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 ).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2022-07-02 20:12:46.500 UTC. The measured peak 
count rate associated with the burst is 117 (+47 -12) counts/s above the 
background in the combined data of all four quadrants, with a total of 
988 (+222 -248) counts. The local mean background count rate was 474 (+4 
-5) counts/s. Using cumulative rates, we measure a T90 of 16 (+1 -4) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve showed multiple peaks 
of emission with the strongest peak at 2022-07-02 20:12:47.671 UTC. The 
measured peak count rate is 208 (+67 -40) counts/s above the background 
in the combined Veto data of all quadrants, with a total of 1533 (+352 
-382) counts. The local mean background count rate was 1405 (+5 -6) 
counts/s. We measure a T90 of 18 (+1 -5) s from the cumulative Veto 
light curve.

CZTI GRB detections are reported regularly on the payload site at 
http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led 
consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.

The Fermi GBM team reports the detection of a likely LONG GRB.

At 20:12:46.60 UT on 2 July 2022, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 220702B (trigger 678485571 / 220702842).

The on-ground calculated location, using the Fermi GBM trigger data, is RA
= 170.7, Dec = 46.8 (J2000 degrees, equivalent to J2000 11h 22m, 46d 48'),
with a statistical uncertainty of 5.5 degrees.

The angle from the Fermi LAT boresight is 65 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220705282/quicklook/glg_skymap_all_bn220702842.png

The HEALPix FITS file, including the estimated localization systematic, can
be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220705282/quicklook/glg_healpix_all_bn220702842.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220705282/quicklook/glg_lc_medres34_bn220702842.gif