GRB 220507A

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

At 10:09:05.75 UT on 7 May 2022, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 220507A (trigger 673610950 / 220507423).

The on-ground calculated location, using the Fermi GBM trigger data, is 
RA = 222.1, Dec = 53.2 (J2000 degrees, equivalent to J2000 14h 48m, 53d 13'),
with a statistical uncertainty of 3.7 degrees.

The angle from the Fermi LAT boresight is 54 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220507423/quicklook/glg_skymap_all_bn220507423.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/bn220507423/quicklook/glg_healpix_all_bn220507423.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220507423/quicklook/glg_lc_medres34_bn220507423.gif

R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A. 
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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 220507A which was 
also detected by Fermi-GBM (GCN #32009
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 ).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaked at 2022-05-07 10:09:07.35 UT. The measured peak count 
rate associated with the burst is 466 (+188, -32) counts/s above the 
background in the combined data of three quadrants, with a total of 527 
(+145, -147) counts. The local mean background count rate was 366 (+7, 
-10) counts/s. Using cumulative rates, we measure a T90 of 5 (+1, -1) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaked at 2022-05-07 
10:09:07.21 UT. The measured peak count rate is 647 (+73, -81) counts/s 
above the background in the combined Veto data of four quadrants, with a 
total of 1796 (+412, -458) counts. The local mean background count rate 
was 1500 (+5, -6) counts/s. We measure a T90 of 6 (+11, -3) 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, ISAC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.