TITLE: GCN CIRCULAR NUMBER: 37576 SUBJECT: GRB 240414A: further radio observations with the VLA DATE: 24/09/20 14:43:52 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 01:21:27 UT on 2024 April 23 (T_mid = 8.98 days post-burst) and at 05:22:12 on 2024 May 15 (T_mid = 31.15 days post-burst) the Karl G. Jansky VLA started observing the field of GRB 240414A (Caputo et al., GCN 36083) at a central frequency of 6 and 10 GHz.

The standard J1331+3030 (3C286) was used as bandpass and flux density calibrator, while J1217+5835 was used as complex gain calibrator.

From a preliminary analysis, the radio source coincident with GRB 240414A (Rhodes et al., GCN 36229; Giarratana et al., GCN 36231; de Ugarte Postigo et al., GCN 36318) is detected at both frequencies:

================================================================ T_mid    Freq     Peak    r.m.s.   Beam      PA [days]   [GHz]    [uJy/b] [uJy/b] [arcsec] [deg] ================================================================ 8.98    6    33    9      4.64x3.44  -86 8.98    10    48    7    3.16x2.24 -82 31.15 6 18 6 1.15x0.92 -40 31.15 10 21 6 0.67x0.56 -38 ================================================================

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 SF161095, approved in the framework of the Fermi - NRAO joint program agreement.

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