{
  "subject": "GRB 251202A: radio detection with the VLA",
  "createdOn": 1765816736030,
  "eventId": "GRB 251202A",
  "submitter": "Stefano Giarratana at INAF-OAB <s.giarratana@ira.inaf.it>",
  "body": "S. Giarratana (INAF-OAB), M. Giroletti (INAF-IRA),\nG. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.),\nN. Omodei (Stanford Univ.), O. S. Salafia (INAF-OAB),\nL. Nava (INAF-OAB)\n\nAt 12:00:00 UT on 2025 December 5 (T_mid = 3.45 days post-burst)\nthe Karl G. Jansky VLA observed the field of GRB 251202A /\nEP251202A (Fermi GBM team, GCN 42933, 42957; Einstein Probe team,\nGCN 42937, GCN 42946; AstroSat CZTI collaboration, GCN 42967;\nInsight-HXMT team, GCN 42970; SVOM team, GCN 42997) in three\nbands, with central frequencies of 6, 10 and 15 GHz.\n\nThe standard 3C286 was used as bandpass and flux density\ncalibrator, while J0818+4222 was used as phase calibrator.\n\nFrom a preliminary analysis, an unresolved radio source\nis detected at a position (J2000):\n\nRA: 08:08:27.466 +- 0.001\nDec: +40:36:44.70 +- 0.01\n\nconsistent with the X-ray (Einstein Probe team, GCN 42937;\nSwift-XRT team, GCN 42943) and optical (GOTO collaboration,\nGCN 42947; Quirola-Vasquez, GCN 42948; Swift/UVOT team,\nGCN 42956; KAIT GRB team, GCN 42964; SVOM/VT team, GCN 42966;\nBochenek et al., GCN 42977; Contreras et al., GCN 42999)\nposition of the transient.\n\nThe preliminary analysis yields the following results:\n\n================================================================\nT_mid\tFreq\tPeak\tr.m.s.\tBeam\t\tPA\n[days]\t[GHz]\t[uJy/b]\t[uJy/b]\t[arcsec^2]\t[deg]\n================================================================\n3.45\t6\t111\t10\t1.08x1.02\t57\n3.45\t10\t169\t7\t0.71x0.60\t59\n3.45\t15\t310\t8\t0.45x0.42\t34\n================================================================\n\nNo source is detected with a >3sigma confidence level at the\naforementioned position in the VLASS. However, the r.m.s. noise\nlevel of the survey at the GRB location is approximately 130 uJy/b.\n\nWe would like to thank the staff of the VLA for approving, executing,\nand processing the observations.\n\nThe National Radio Astronomy Observatory is a facility of the National\nScience Foundation operated under cooperative agreement by Associated\nUniversities, Inc.\n\nThese observations were carried out as part of project SF181027,\napproved in the framework of the Fermi - NRAO joint program agreement.",
  "bibcode": "2025GCN.43128....1G",
  "submittedHow": "email",
  "circularId": 43128
}