TITLE: GCN CIRCULAR NUMBER: 38130 SUBJECT: GRB 241025A: radio detection with the VLA DATE: 24/11/08 16:21:52 GMT FROM: Stefano Giarratana at INAF-OAB s.giarratana@ira.inaf.it
S. Giarratana (INAF-OAB), M. Giroletti (INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.), N. Omodei (Stanford Univ.), O. S. Salafia (INAF-OAB)
At 19:11:50 UT on 2024 Oct 25 (T_mid = 0.76 days post-burst) the Karl G. Jansky VLA observed the field of GRB 241025A (Ambrosi et al., GCN 37859; Fermi GBM team, GCN 37860; SVOM team, GCN 37863; Li et al., GCN 37864; Svinkin et al., GCN 37927) in three bands, with central frequencies of 6, 10 and 15 GHz.
The standard 3C286 was used as bandpass and flux density calibrator, while J2344+8226 was used as phase calibrator.
From a preliminary analysis, an unresolved radio source is clearly detected at a position (J2000):
RA: 22:14:36.859 +- 0.001 Dec: +83:34:32.27 +- 0.02
consistent with the optical (Ambrosi et al., GCN 37859; Klingler et al., GCN 37919) and X-ray (Goad et al., GCN 37868) position of the transient.
The preliminary analysis yields the following results:
============================================================= T_mid Freq Peak r.m.s. Beam PA [days] [GHz] [uJy/b] [uJy/b] [arcsec^2] [deg] ============================================================= 0.76 6 51 7 0.65x0.27 -71 0.76 10 119 8 0.35x0.17 -78 0.76 15 163 8 0.24x0.12 -65 =============================================================
No source is detected with a >3sigma confidence at the aforementioned position in previous radio surveys (FIRST, NVSS, VLASS), all of which have r.m.s. noise levels above 100 uJy/b.
We would like to thank the staff of the VLA for approving, executing, and processing the observations.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
These observations were carried out as part of project SF171028, approved in the framework of the Fermi - NRAO joint program agreement.
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