TITLE:   GCN CIRCULAR
NUMBER:  38286
SUBJECT: EP241119a : J-band observations with WINTER
DATE:    24/11/20 21:47:58 GMT
FROM:    Tomas Ahumada Mena at Caltech <tahumada@caltech.edu>

Tomas Ahumada (Caltech), Geoffrey Mo (MIT), Benjamin Schneider (MIT), Viraj Karambelkar (Caltech), Robert Stein (UMD), Danielle Frostig (CfA), Nathan Lourie (MIT), Mansi Kasliwal (Caltech), and Robert Simcoe (MIT) report:

We observed the field of the EP-WXT and EP-FXT X-ray transient EP241119a (Zhang et al., GCN 38281) in the near-infrared J-band with the Palomar 1-m telescope, equipped with the 1 square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024). 

Observations began at 2024-11-20T11:50:08.437 UTC (~18 hrs after the X-ray transient) and consisted of 30 x 120 s exposures. The images were processed using the WINTER data reduction pipeline (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565). 

No source is detected in the FXT error region (Zhang et al., GCN 38281), setting a 5-sigma upper limit of 18.5 mag (AB) in the J band. We note there is a stellar object (18.99 AB mag in the SDSS r-band) within the 10 arcsec error region of the FXT localization.

WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research.