{
  "submittedHow": "web",
  "circularId": 40036,
  "eventId": "GRB 250322A",
  "format": "text/plain",
  "submitter": "Genevieve Schroeder at Cornell University <genevieveschroeder@u.northwestern.edu>",
  "bibcode": "2025GCN.40036....1S",
  "createdOn": 1743731541133,
  "subject": "GRB 250322A: 10 GHz VLA radio upper limits",
  "body": "G. Schroeder (Cornell), T. Laskar (Utah), W. Fong, J. Rastinejad (Northwestern) report:\n\nWe observed the position of the short GRB 250322A (Gupta et al., GCN 39835;\nTembhurnikar et al., GCN 39849; Ridnaia et al., GCN 39873) with the Karl G. Jansky Very Large Array (VLA) under program 25A-063 (PI Schroeder) beginning on 2025 March 25 at 22:07 UT (3.25 days post-burst) for 1 hour at a mean frequency of 10 GHz.\n\nBased on preliminary analysis, we do not detect any radio emission at or near the position of the XRT afterglow (Perri et al., GCN 39855), to a 3 sigma limit of 20 microJy. We additionally do not detect the putative host galaxy in our image (Martin-Carrillo et al., GCN 39842; Becerra et al., GCN 39844; 39845l; Kilpatrick & Fong, GCN 39846; Fong et al., GCN 39852, Schneider et al., GCN 39863). Assuming a redshift of z = 0.42 (Fong et al., GCN 39852; Yang et al. GCN 39859), these observations imply a limit on the radio-inferred star formation rate of < 18 M_sol/year (following the formalism of Greiner et al. 2016). Using the putative host redshift, the lack of radio afterglow detection implies a radio luminosity of < 1.3e29 erg/Hz/s, which is a factor of >~4 lower than the median radio luminosity of radio-detected short GRBs at a similar epoch and rest frame time (Laskar et. al. 2022). Overall, this limit places GRB 250322A in the bottom 25% of radio-observed short GRBs with redshift determinations, in terms of radio luminosity.\n\nWe thank the VLA staff for quickly approving and executing these observations."
}