GRB 230310A

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

At 00:45:01 UT on 10 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230310A (trigger 700101906.130722 / 230310031).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 257.6, Dec = -23.5 (J2000 degrees, equivalent to J2000 17h 10m, -23d 30'), with a statistical uncertainty of 7.2 degrees.

The angle from the Fermi LAT boresight is 120.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230310031/quicklook/glg_skymap_all_bn230310031.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/bn230310031/quicklook/glg_healpix_all_bn230310031.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230310031/quicklook/glg_lc_medres34_bn230310031.gif

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230310A ( Fermi GBM team, GCN 33445
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 ) errorbox  187 sec after notice time and 218 sec after trigger time at 2023-03-10 00:48:39 UT, with upper limit up to  18.0 mag. The observations began at zenith distance = 54 deg. The sun  altitude  is -43.8 deg. 

The galactic latitude b =  9 deg., longitude l =  1 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2203155

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     249 | 2023-03-10 00:48:39 |         MASTER-SAAO | (17h 11m 56.73s , -17d 55m 16.0s) |   C |    60 | 18.0 |        
     249 | 2023-03-10 00:48:39 |         MASTER-SAAO | (17h 11m 04.28s , -17d 54m 58.3s) |   C |    60 | 17.9 |        
     339 | 2023-03-10 00:50:09 |         MASTER-SAAO | (17h 20m 26.28s , -17d 55m 05.0s) |   C |    60 | 17.4 |        
     339 | 2023-03-10 00:50:09 |         MASTER-SAAO | (17h 19m 33.91s , -17d 54m 48.7s) |   C |    60 | 17.3 |        
     418 | 2023-03-10 00:51:29 |         MASTER-SAAO | (17h 17m 28.93s , -16d 01m 23.8s) |   C |    60 | 18.0 |        
     418 | 2023-03-10 00:51:29 |         MASTER-SAAO | (17h 16m 37.06s , -16d 01m 07.8s) |   C |    60 | 17.7 |        
     510 | 2023-03-10 00:53:01 |         MASTER-SAAO | (17h 25m 51.99s , -15d 59m 37.5s) |   C |    60 | 17.7 |        
     510 | 2023-03-10 00:53:01 |         MASTER-SAAO | (17h 25m 00.18s , -15d 59m 22.0s) |   C |    60 | 17.6 |        
     604 | 2023-03-10 00:54:34 |         MASTER-SAAO | (17h 07m 28.98s , -19d 47m 03.3s) |   C |    60 | 18.0 |        
     604 | 2023-03-10 00:54:34 |         MASTER-SAAO | (17h 06m 35.75s , -19d 46m 48.4s) |   C |    60 | 17.9 |        
     684 | 2023-03-10 00:55:54 |         MASTER-SAAO | (17h 16m 04.51s , -19d 48m 20.0s) |   C |    60 | 17.8 |        
     684 | 2023-03-10 00:55:54 |         MASTER-SAAO | (17h 15m 11.34s , -19d 48m 05.3s) |   C |    60 | 17.6 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.

M. Dixit (IITB), G. Waratkar (IITB), P K. Navaneeth (IUCAA), 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 230310A which was 
also detected by Fermi GBM (GCN Circ. 33445
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 ).

The source was faintly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-03-10 00:44:58.0 UTC. The measured peak count 
rate associated with the burst is 96.2 (+25.5, -26.2) counts/s above the 
background in the combined data of all quadrants, with a total of 562 
(+167, -183) counts. The local mean background count rate was 427.7 
(+1.7, -2.8) counts/s. Using cumulative rates, we measure a T90 of 10.13 
(+3.21, -4.21) s.

It was also faintly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2023-03-10 
00:44:58.0 UTC. The measured peak count rate is 329.8 (+66.1, -68.7) 
counts/s above the background in the combined Veto data of three 
quadrants, with a total of 1912 (+530, -584) counts. The local mean 
background count rate was 2798.0 (+6.4, -7.1) counts/s. We measure a T90 
of 13.94 (+3.25, -5.91) s from the cumulative Veto light curve.

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.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb