GCN Circular 42251

Subject

GRB 251013C: ABObservatory optical observations

Event

GRB 251013C

Date

2025-10-14T10:53:56Z (2 days ago)

Edited On

2025-10-14T14:24:18Z (2 days ago)

From

A. Brosio at ABObservatory Rosarno <antonino.brosio@gmail.com>

Edited By

Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of A. Brosio at ABObservatory Rosarno <antonino.brosio@gmail.com>

Via

Web form

A. Brosio (ABObservatory Rosarno), M. A. Tripodi (ABObservatory Rosarno), S. Savaglio (University of Calabria), G. Bracco,  P. Cianfarra, L. Sangaletti, S. Tosi & S. Zappatore (University of Genoa), S. Benatti & M. G. Guarcello (INAF Palermo), L.Cabona, M. Rainer, F. M. Zerbi, M. Basilicata (INAF Brera), D. Ricci (INAF Padova), A. Di Dato (INAF Capodimonte), S. Masiero & A. Nastasi (GAL Hassin), D. Liguori (Osservatorio "G. Galilei" Cariati), L. Betti (Osservatorio Polifunzionale del Chianti), R. Nesci (Associazione Astronomica Antares APS di Foligno), for the NOCTIS team report

We observed the field of GRB 251013C, which was detected by Fermi GBM team (GCN 42221Loading...
 
 ) with the 30-cm automated telescope at ABObservatory (Rosarno, Italy) in V filter. 
The observations began on 2025 october 13 at 20:56:53 UT, approximately 2.38 hours after the trigger. The observation consisted of 50 exposures of 120 seconds each,with good sky conditions.
The mid-exposure time was 22:12:46 UT, and the final exposure ended at 23:32:52 UT.

From photometry, we detect the optical counterpart in our images at the following coordinates:
R.A (J2000.0)  =  23 03 19.712
Dec. (J2000.0) = -00 12 53.17

The measured magnitude at JD 2460962.37284 is:
16.86 +/- 0.06 in V band with SNR 14.98 (AB, calibrated with the GAIA DR3 on SIMBAD).

We also obtained a decay curve which, during the period we monitored the object, showed a decline down to magnitude +17.848 +/-0.275 at 23:27:57 UT