GCN Circular 42228

Subject

GRB 251013C: Optical Observations via Virtual Telescope Project, Italy

Event

GRB 251013C

Date

2025-10-13T21:07:58Z (3 days ago)

From

Gianluca Masi at Virtual Telescope Project <gianluca@bellatrixobservatory.org>

Via

Web form

Gianluca Masi, Virtual Telescope Project (Italy), reports:

We attempted to observe the optical counterpart of GRB 251013C (Rakotondrainibe et al., GCN 42222Loading...
 
 ) with the 14” robotic unit available at the Virtual Telescope Project facility in Manciano, Italy, equipped with a KAF-3200E based CCD camera, its QE peaking (90%) in the red part of the spectrum.

We collected three, 120-second unfiltered exposures, then we averaged them. The central time of the resulting stack was 13 Oct., 20:54:57 UTC, that is about 3.25 hours after the burst.

We detected a bright object at the following position (J2000.0):

R.A.: 23 03 20.56
Decl.: -00 13 37.1
mean residuals < 1” on both axes
R= 15.9 (assuming R-mags from Gaia DR2 for the reference stars).

This position is consistent with Palmerio et al. (GCN 42223Loading...
 
 )and  Perez-Garcia et al., GCN 42225Loading...
 
 .