GCN Circular 38334
Subject
LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
Date
2024-11-27T01:54:00Z (a year ago)
From
Alan Watson at UNAM <alan@astro.unam.mx>
Via
email
D. Akl (AUS), S. Antier (OCA), J.-G. Ducoin (CPPM), Francesco Magnani
(CPPM), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H.
Lee (UNAM), Jean-Luc Atteia (IRAP), Nathaniel R. Butler (ASU), Damien
Dornic (CPPM), Francis Fortin (IRAP), Simona Lombardo (LAM), and
Margarita Pereyra (UNAM) report:
We imaged the field of the Swift/BAT-GUANO candidate counterpart
(DeLaunay et al., GCN Circ. 38308) of the GW compact binary merger
candidate S241125n (LIGO/Virgo/KAGRA Collaborations, GCN Circ. 38305)
during the commissioning of the COLIBRÍ (SVOM/F-GFT) telescope at the
Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in
Mexico.
We observed with the engineering test camera in a red filter that
approximates SDSS r from 2024-11-26 02:08 to 07:50 UTC (25.1 to 30.8
hours after the event) and obtained 255 minutes of exposure on a field
about 12 arcmin to a side centered on the BAT position given by
DeLaunay et al. (GCN Circ. 38308). Results from a subset of these
observations were reported by Watson et al. (GCN Circ. 38317).
Our image includes the positions of the S241125n_X3 and S241125n_X5
XRT sources (Page et al., GCN 38324). We do not detect any clear
candidates within the localization regions of these sources to a
3-sigma upper limit of
r > 23.4
Our upper limits are consistent with GCN. 38314, 38325, GCN 38328, GCN 38329.
We warmly thank the COLIBRÍ engineering team and the staff of the
Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir.
We warmly thank the GRANDMA IJCLAB team and S. Karpov for the access
of the STDWeb service for STDPipe.