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TITLE:   GCN CIRCULAR
NUMBER:  29707
SUBJECT: GRB 210324A: Fermi GBM Final Real-time Localization
DATE:    21/03/24 11:24:43 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

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

At 11:14:28 UT on 24 Mar 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210324A (trigger 638277273.212466 / 210324468).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 148.5, Dec = 37.2 (J2000 degrees, equivalent to J2000 09h 54m, 37d 12'), with a statistical uncertainty of 3.1 degrees.

The angle from the Fermi LAT boresight is 76.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210324468/quicklook/glg_skymap_all_bn210324468.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210324468/quicklook/glg_healpix_all_bn210324468.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210324468/quicklook/glg_lc_medres34_bn210324468.gif

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TITLE:   GCN CIRCULAR
NUMBER:  29735
SUBJECT: GRB 210324A: AstroSat CZTI detection
DATE:    21/03/30 11:05:00 GMT
FROM:    Gaurav Waratkar at IIT Bombay  <gauravwaratkar24@gmail.com>

P.  Sawant (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), S. Gupta
(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, 2020,
arxiv:2011.07067) showed detection of a long GRB 210324A, which was also
detected by Fermi-GBM (GCN #29707).

The source was clearly detected in the 20-200 keV energy range. The light
curve showed multiple peaks of emission with the strongest peak at
2021-03-24 11:14:32 UT in two quadrants (out of four). The measured peak
count rate associated with the burst is 165 (+44, -21) cts/s above the
background in the combined data of four quadrants, with a total of 2373
(+286, -392) cts. The local mean background count rate was 490 (+3, -3)
cts/s. Using cumulative rates, we measure a T90 of 33 (+2, -5) s.

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.