TITLE:   GCN CIRCULAR
NUMBER:  35900
SUBJECT: GRB 231215A: further radio observations with the VLA
DATE:    24/03/08 07:53:00 GMT
FROM:    Stefano Giarratana at University of Bologna <s.giarratana@ira.inaf.it>

S. Giarratana (University of Bologna, INAF-IRA), M. Giroletti
(INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.),
N. Omodei (Stanford Univ.)


At 02:46:36 UT on 2023 December 28 (T_mid = 12.7 days post-burst) 
and at 01:39:51 UT on 2024 January 17 (T_mid = 32.7 days 
post-burst) the Karl G. Jansky VLA observed the field of
GRB 231215A (D'Avanzo et al., GCN 35343) at a central frequency
of 6 and 10 GHz. 

The standard J0542+4951 was used as bandpass and flux density
calibrator, while J0102+5824 was used as phase calibrator.

From a preliminary analysis, the radio source coincident with
GRB 231215A (Rhodes et al., GCN 35397; Giarratana et al., GCN 35507)
is still detected. We derive the following surface brightness
peak estimates.

================================================================
T_mid    Freq     Peak     r.m.s.   Beam         PA
[days]   [GHz]    [uJy/b]  [uJy/b] [arcsec]     [deg]
================================================================
12.7     6        110      8        11.69x9.50   -44
12.7     10       127      7        7.06x5.79    -33
32.7     6        48       7        7.34x4.23    -31
32.7     10       62       6        5.27x3.13    -24
================================================================

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.