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GCN Circular 39914

Subject

GRB 250327B: J-band observations with WINTER

Date

2025-03-28T20:44:14Z (16 days ago)

From

Geoffrey Mo at MIT <gmo@mit.edu>

Via

Web form

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

We observed the field of GRB 250327B (Bouchet et al., GCN 39888

) 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 under poor weather conditions at 2025-03-28T10:04:53 UTC (12.9 hours after the GRB), consisting of 13 x 120 s exposures. The images were processed using the WINTER data reduction pipeline implemented with mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565

We do not detect a source at the optical and X-ray counterpart location (Moskvitin et al., GCN 39889

; Xin et al., GCN ; O’Neill et al., GCN ; Malesani et al., GCN ; Lian et al., GCN ; Page et al., GCN ; Shrestha et al., GCN ; Duncoin et al., GCN ; Perley et al., GCN ; Kumar et al., GCN ; Dennefeld et al., GCN ; Pankov et al., GCN ; Pérez-Fournon et al., GCN ). We obtain the following 5-sigma upper limit: J ~ 17.5 mag (AB).

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.