[vsnet-grb-info 24788] GRB 200125A: TNG detection of a NIR counterpart candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26887
SUBJECT: GRB 200125A: TNG detection of a NIR counterpart candidate
DATE:    20/01/26 13:33:30 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <pda.davanzo at gmail.com>

A. Melandri, P. D'Avanzo (INAF-OAB), V. D’Elia (ASI-SSDC), W. Boschin, G. Mainella (INAF-TNG) 
on behalf of the CIBO collaboration report:

We observed the field of GRB 200125A (Lien et al., GCN Circ. 26976) with the Italian 3.58m TNG telescope 
equipped with NICS in imaging mode. A series of images were obtained with the Ks and J filters on 2020-01-26 
from 05:25 to 06:39 UT (i.e. from about 17.9 to 19.1 hours after the burst). 

We detect a source at the following coordinates: 

RA(J2000), Dec (J2000) = 15:12:11.30, -08:08:38.5  (+/- 0.5”).

This position is consistent with the most updated XRT localisation (https://www.swift.ac.uk/xrt_positions/ <https://www.swift.ac.uk/xrt_positions/>). We assume 
this is the same source detectd in the optical by Watson et al. (GCN Circ. 26882). 

>From preliminary photometry, we estimate for this object a magnitude Ks ~ 17.2 (Vega, calibrated assuming K = 12.1 
for the 2MASS star at RA(J2000), Dec (J2000) = 15:12:05.10, -08:07:06.9).