GRB 230304A
GCN Circular 33399
Subject
GRB 230304A: AstroSat CZTI detection
Date
2023-03-06T06:36:26Z (2 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
P K. Navaneeth (IUCAA), R. Gopalakrishnan (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 230304A which was
also detected by Fermi GBM (GCN Circ. 33395).
The source was detected in the 20-200 keV energy range. The light curve
showed multiple peaks of emission with the strongest peak at 2023-03-04
06:21:01.35 UTC. The measured peak count rate associated with the burst
is 292 (+147, -18) counts/s above the background in the combined data of
three quadrants (out of four), with a total of 577 (+223, -214) counts.
The local mean background count rate was 325 (+4, -6) counts/s. Using
cumulative rates, we measure a T90 of 9.73 (+3, -4) s.
It was also detected in the CsI anticoincidence (Veto) detector in the
100-500 keV energy range. The light curve peaks at 2023-03-04 06:21:00.9
UTC. The measured peak count rate is 927 (+77, -84) counts/s above the
background in the combined Veto data of all quadrants, with a total of
5710 (+511, -579) counts. The local mean background count rate was 1423
(+5, -6) counts/s. We measure a T90 of 10.23 (+4, -2) 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.
GCN Circular 33395
Subject
GRB 230304A: Fermi GBM Final Real-time Localization
Date
2023-03-04T06:31:10Z (2 years ago)
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 06:20:54 UT on 4 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230304A (trigger 699603659.15977 / 230304265).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 29.2, Dec = 32.8 (J2000 degrees, equivalent to J2000 01h 56m, 32d 47'), with a statistical uncertainty of 1.6 degrees.
The angle from the Fermi LAT boresight is 103.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304265/quicklook/glg_skymap_all_bn230304265.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304265/quicklook/glg_healpix_all_bn230304265.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304265/quicklook/glg_lc_medres34_bn230304265.gif