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GCN Circular 36231

GRB 240414A: radio detection with the VLA
2024-04-22T16:59:02Z (a month ago)
Stefano Giarratana at University of Bologna <>
S. Giarratana (INAF-OAB), M. Giroletti (INAF-IRA),
G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.),
N. Omodei (Stanford Univ.)

At 01:42:45 UT on 2024 April 17 (T_mid = 2.99 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, an unresolved radio source is clearly
detected at both frequencies at a position:

RA: 12:19:08.08 +- 0.01
Dec: +56:44:28.7 +- 0.2

The surface brightness peak is 40 uJy/beam and 60 uJy/beam at 6
and 10 GHz, respectively. The r.m.s. noise level of the images is
7 uJy/beam at both 6 and 10 GHz.

The synthesized beams are 4.1 x 3.0 arcsec (PA: 70deg) at 6 GHz
and 2.7 x 1.9 arcsec (PA: 76deg) at 10 GHz.

While no source is detected at the aforementioned position in previous
radio surveys (FIRST, NVSS, VLASS), their r.m.s. noise levels (1sigma)
is above 100 uJy/b, well above the derived surface brightness peak.
Therefore, we cannot exclude the contribution from the GRB host galaxy yet.

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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