TITLE: GCN CIRCULAR NUMBER: 39520 SUBJECT: GRB 250205A / EP250205A: further radio observations with the VLA DATE: 25/02/27 15:43:06 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 06:32:26 UT on 2025 Feb 8 (T_mid = 2.41 days post-burst) and at 05:58:32 UT on 2025 Feb 13 (T_mid = 7.39 days post-burst) the Karl G. Jansky VLA observed the field of GRB 250205A / EP250205A (Saccardi et al., GCN 39154; Mukherjee et al., GCN 39171) in three bands, with central frequencies of 6, 10 and 15 GHz.
The standard 3C286 was used as bandpass and flux density calibrator, while J0741+3112 was used as phase calibrator.
The preliminary analysis yields the following results:
================================================================ T_mid Freq Peak U.L. r.m.s. Beam PA [days] [GHz] [uJy/b] [uJy] [uJy/b] [arcsec^2] [deg] ================================================================ 2.41 6 - 21 7 0.34x0.31 47 2.41 10 38 - 8 0.23x0.20 49 2.41 15 - 21 7 0.14x0.12 34 7.39 6 - 24 8 0.38x0.31 65 7.39 10 - 21 7 1.47x0.16 68 7.39 15 - 24 8 0.16x0.12 54 ================================================================
where U.L. are the upper limits (3 sigma) for the non-detections.
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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