GCN Circular 46016
Subject
EP261015a: VLA non-detection
Event
Date
2026-10-23T19:57:45Z (4 days ago)
From
Laura Cotter at University College Dublin <laura.cotter@ucdconnect.ie>
Via
Web form
L. Cotter (Cornell), D. Perley (LJMU) and A. Y. Q. Ho (Cornell) report on behalf of a larger collaboration,
We observed the field of EP261015a (Li et al., GCN 45956) with the Karl G. Jansky Very Large Array (VLA) in C configuration under program 25B-363 (PI: Daniel Perley) at a mid time of 2026 October 22 at 10:15 UT, approximately 6.87 days post trigger. The observations lasted 58 minutes at a mean frequency of 10 GHz.
In the preliminary analysis, we do not detect any radio sources at or near the position of the optical counterpart (Corcoran et al., GCN 45955) to a 3-sigma limit of < 17 microJy.
Taking the photometric redshift of 0.57 from the potential underlying host galaxy, this limit corresponds to a rest-frame luminosity of < 1.43e+29 erg/s/Hz. Comparing this to previously detected EP transients, this limit is ~ 2 orders of magnitude below the radio luminosities of GRB 240315C/EP240315A and EP241021A at comparable epochs (e.g. Choza et al. 2026). This limit also lies below the typical luminosities of radio-detected short GRBs at early rest-frame times (e.g., Anderson et al. 2025). However, the limit remains above the radio luminosities measured for some relativistic SNe and low-luminosity GRB-SNe like GRB980425/SN1998bw (e.g. Kulkarni et al 1998), and therefore does not rule out an origin similar to these events.
We thank the operators at the VLA for carrying out our observations.