GCN Circular 41023
Subject
GRB 250702F: radio detection with the VLA
Event
Date
2025-07-08T12:10:37Z (a year ago)
From
Stefano Giarratana at INAF-OAB <s.giarratana@ira.inaf.it>
Via
email
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),
L. Nava (INAF-OAB)
At 02:54:00 UT on 2025 July 6 (T_mid = 3.27 days post-burst)
the Karl G. Jansky VLA observed the field of GRB 250702F
(Fermi GBM team, GCN 40892; Klingler et al., GCN 40894;
Frederiks et al., GCN 40948) in three bands, with central
frequencies of 6, 10 and 15 GHz.
The standard 3C286 was used as bandpass and flux density
calibrator, while J1415+1320 was used as phase calibrator.
From a preliminary analysis, an unresolved radio source
is detected at a position (J2000):
RA: 14:11:44.641 +- 0.004
Dec: +16:44:54.68 +- 0.06
consistent with the X-ray (Goad et al., GCN 40902;
Liang et al., GCN 40967) and optical (Klingler et al.,
GCN 40894; Jelinek et al., GCN 40895; Kumar et al., GCN 40896;
Lipunov et al., GCN 40899; Martin-Carrillo et al., GCN 40900;
de Ugarte Postigo et al., GCN 40901; Angulo et al., GCN 40907;
Becerra et al., GCN 40911; Brivio et al., GCN 40913; An et al.,
GCN 40916; Dutton et al., GCN 40921; Odeh et al., GCN 40925;
Moretti et al., GCN 40926; Siegel et al., GCN 40933; Ma et al.,
GCN 40936; Vinko et al., GCN 40939; Mohan et al., GCN 40946;
Ciabattari et al., GCN 40968; Broens et al., GCN 40969;
Calapai et al., GCN 40973; Antier et al., GCN 41011) 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]
================================================================
3.27 6 158 7 3.31x3.03 22
3.27 10 127 6 2.09x1.95 31
3.27 15 141 7 1.39x1.26 1
================================================================
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.