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TITLE:   GCN CIRCULAR
NUMBER:  33232
SUBJECT: GRB 230129A: Fermi GBM Final Real-time Localization
DATE:    23/01/29 06:16:36 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 SHORT GRB

At 06:05:21 UT on 29 Jan 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230129A (trigger 696665126.147626 / 230129254).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 111.9, Dec = 2.4 (J2000 degrees, equivalent to J2000 07h 27m, 2d 23'), with a statistical uncertainty of 22.6 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/2023/bn230129254/quicklook/glg_skymap_all_bn230129254.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/bn230129254/quicklook/glg_healpix_all_bn230129254.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230129254/quicklook/glg_lc_medres34_bn230129254.gif

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TITLE:   GCN CIRCULAR
NUMBER:  33236
SUBJECT: GRB 230129A: AstroSat CZTI detection
DATE:    23/01/30 16:18:48 GMT
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 short GRB 230129A which was 
also detected by Fermi GBM (GCN Circ. 33232).

The source was faintly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-01-29 06:05:21.15 UTC. The measured peak count 
rate associated with the burst is 300 (+148, -38) counts/s above the 
background in the combined data of all quadrants, with a total of 161 
(+48, -54) counts. The local mean background count rate was 319 (+7, 
-12) counts/s. Using cumulative rates, we measure a T90 of 0.78 (+0.37, 
-0.36) s. We note that the T90 measurement may be a slight underestimate 
due to the limited number of photons detected from the burst.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range.

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.