GCN Circular 39842
Subject
GRB 250322A: NOT optical upper limits
Date
2025-03-22T23:10:07Z (5 days ago)
From
Antonio Martin-Carrillo at UCD,Space Science Group <antonio.martin-carrillo@ucd.ie>
Via
Web form
A. Martin-Carrillo (UCD), B. Schneider (LAM), D. B. Malesani (DAWN/NBI and Radboud Univ.), L. Izzo (INAF/OACn and DARK/NBI), D. Xu (NAOC), A. A. Djupvik (NOT), and A. Kadela (NOT and NBI), report on behalf of a larger collaboration:
We observed the field of the GRB 250322A (Gupta et al., GCN 39835) using the ALFOSC camera mounted on the Nordic Optical Telescope (NOT). We obtained 5 exposures of 300 s each in the SDSS-r and SDSS-z band, starting at 20:45:22 UT on 2025-03-22 (4.65 hr after the trigger).
Preliminary analysis shows that no new source is detected within the Swift/XRT enhanced error box (Goad et al., GCN 39841), down to the 5-sigma AB limiting magnitudes r > 24.3 and z > 22.6, calibrated with nearby Pan-STARRS stars and without Galactic extinction correction.
We note that the XRT location includes an extended object (J2000 coordinates RA = 07:07:02.60, Dec = +07:11:33.8) also visible in the Pan-STARRS images, which is a host galaxy candidate for the GRB. Photometry of this source reveals a magnitude consistent with that reported in the Pan-STARRS catalogue, indicating no bright additional component on top of it.