TITLE:   GCN CIRCULAR
NUMBER:  42535
SUBJECT: GRB 251103A: NOT optical afterglow candidate
DATE:    25/11/03 05:57:12 GMT
FROM:    Benjamin Schneider at MIT <bschn@mit.edu>

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 42534) 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.