GCN Circular 42535

Subject

GRB 251103A: NOT optical afterglow candidate

Event

GRB 251103A

Date

2025-11-03T05:57:12Z (2 days ago)

Edited On

2025-11-03T16:23:43Z (a day ago)

From

Benjamin Schneider at MIT <bschn@mit.edu>

Edited By

Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Benjamin Schneider at MIT <bschn@mit.edu>

Via

Web form

B. Schneider (LAM), D. B. Malesani (DAWN/NBI and Radboud), D. Xu (NAOC), S. Bijavara Seshashayana (NOT and Malmo Univ.) report on behalf of a larger collaboration:

We observed the field of GRB 251103A (Hu et al., GCN 42534Loading...
 
 ) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. Observations started on 2025-11-03 at 05:25:50 UT (39.5 min after trigger) and consisted of 2x300 s in the SDSS r band.

Within the ECLAIRs error circle, we detect a new source which is not seen in Pan-STARRS archival imaging of this field. Its coordinates are:

RA(J2000) = 09:47:21.41
Dec(J2000) = +16:07:21.8

with an estimated error of 0.3". Calibrated against nearby objects from Pan-STARRS, we measure AB magnitudes (not corrected for Galactic extinction):

r = 17.07 +/- 0.03

Further observations are ongoing.