GCN Circular 38233
Subject
EP 241113a: LBT possible optical counterpart
Date
2024-11-15T10:38:26Z (a month ago)
From
Andrea Rossi at INAF <andrea.rossi@inaf.it>
Via
Web form
A. Rossi (INAF/OAS), A.J. Levan (Radboud Univ.), D. B. Malesani (DAWN/NBI and Radboud Univ.), P.G. Jonker (Radboud Univ.), J. Rastinejad (Northwestern), E. Maiorano (INAF/OAS), report on behalf of a larger collaboration:
We observed the field of EP 241113a (Liu et al., GCN 38211) with the LBC camera mounted on LBT (Mt. Graham, AZ, USA) in the r' band (22 min of exposure time) with approximate midtime 07:45:00 UT on 2024-11-15, or 1.52 days after the burst. Observations were performed under an average seeing of ~1.5".
We detect a very faint source within the EP/WXT error circle, which is not present in Legacy Survey r-band images, and is located at coordinates (J2000):
RA = 08:47:59.39
Dec = +52:22:54.7
We measure a preliminary AB magnitude of
r' = 23.35 +- 0.15,
calibrated against Pan-STARRS field stars, and not corrected for the foreground Galactic extinction.
We note that the candidate afterglow is offset ~20” from the galaxy 2MASX J08480182+5222544 with a measured spectroscopic redshift of z=0.115. This corresponds to ~40 kpc in projection and the probability of chance alignment is approximately 3%.
We acknowledge excellent support from the LBTO and LBT-INAF staff, particularly A. Becker and D. G. Huerta.