GCN Circular 43182
Subject
EP251220a: NOT optical observations
Event
Date
2025-12-22T14:18:06Z (3 days ago)
Edited On
2025-12-22T21:29:31Z (3 days ago)
From
Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani@nbi.ku.dk>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani@nbi.ku.dk>
Via
Web form
A. P. C. van Hoof (Radboud), G. Corcoran (UCD), J. An (NAOC), R. A. J. Eyles-Ferris (U. Leicester), D. B. Malesani (DAWN/NBI and Radboud), D. Xu (NAOC), J. Sanchez-Sierras (Radboud), P. G. Jonker (Radboud), A. Martin-Carrillo (UCD), A. Kadela (NOT and NBI), report on behalf of a larger collaboration:
We observed the optical counterpart (Sánchez Álvarez et al., GCN 43167; Kumar et al., GCN 43169; Rakotondrainibe et al., GCN 43170; Busmann et al., GCN 43181) of EP251220a (Liu et al., GCNs 43162, 43172) with the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. A sequence of 4x300 s exposures were taken in SDSS r-band starting on 2025-12-21 at 19:37:19.906 UT (~35.18 hr since the EP trigger).
The source is well detected in the stacked image with a preliminary photometry of
r = 21.79 +/- 0.05 (AB),
calibrated against nearby stars from the Pan-STARRS catalog and not corrected for Galactic extinction. Our photometry is consistent with the temporal index found by Rakotondrainibe et al. (GCN 43170).