TITLE: GCN CIRCULAR NUMBER: 39604 SUBJECT: GRB250101A: Radio upper limits from VLA observations DATE: 25/03/06 15:57:17 GMT FROM: Arvind Balasubramanian arvind6895@gmail.com
A. Balasubramanian (IIA), A.P. Saikia (IITB), V. Swain (IITB), G.C. Anupama (IIA), S. Barway (IIA), V. Bhalerao (IITB) report
We observed the field of the gamma ray burst GRB250101A (Page et al. GCN 38752, Li et al. GCN 38753, Mohan et al. GCN 38754, Zhu et al. GCN 38755, Budnev et al. GCN 38756, Wu et al. GCN 38758, Odeh et al. GCN 38763, Balasubramanian et al. GCN 39307) with the Jansky Very Large Array (VLA) under the DDT 24B-529 (PI: A. Balasubramanian) on 13th February 2025 in S Band (3 GHz) for about 1.5 hours starting at 02:06 hours UTC.
We do not detect any significant radio emission at the position of the optical counterpart (Li et al. GCN 38753). We used 3C47 for the flux calibration and J0238+1636 for complex gain and phase calibration. The CASA calibration and imagining pipeline (version 6.5.4.9) was used for data calibration and imaging. We compute a 3-sigma upper limit of ~805 uJy at 3 GHz. Further analysis is in progress.
We thank the TAC and operations team of VLA for making these observations possible. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
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