TITLE: GCN CIRCULAR NUMBER: 39589 SUBJECT: EP250304a: REM NIR upper limits DATE: 25/03/04 13:00:46 GMT FROM: Riccardo Brivio at INAF-OAB riccardo.brivio@inaf.it

R. Brivio, M. Ferro (INAF-OAB), D. B. Malesani (DAWN/NBI and Radboud), P. D’Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team:

We observed the field of EP250304a (Chen et al., GCN 39580) with the REM 60 cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the J, H, and K bands, started on 2025 March 04 at 01:46:18 UT (i.e. 0.23 hr after the burst), and lasted for about 2 hours.

From preliminary analysis, we do not find any NIR counterpart at the position of the reported optical afterglow (Liu et al., GCN 39583; Saccardi et al., GCN 39585) down to the following 3sigma limit:

J > 17.5 (Vega; calibrated against the 2MASS catalogue),

at a mid-time of 1.46 hours after the trigger.

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