GCN 44057: NOEMA Detection of GRB 260310A / AT 2026fgk

Anna Y. Q. Ho (Cornell), Michael Bremer (IRAM), Genevieve Schroeder (Cornell) report on behalf of a larger collaboration:

On UT 2026 March 20 the NOrthern Extended Millimeter Array (NOEMA) observed the position of GRB 260310A / AT2026fgk (GCN 43951, 43958, 43974), a nearby (z=0.153; GCN 43977) gamma-ray burst with bright radio emission at cm wavelengths (GCN 44005, 44045). Observations were obtained in the new dual-band mode (100+230 GHz) as well as in Band 2 (150 GHz). With self-calibration, we measure a preliminary flux density of 17 mJy at 100 GHz, corresponding to a luminosity of 10^42 erg/s, typical for GRB afterglows at this epoch. 

Further observations are planned. We thank the NOEMA staff for rapidly approving and scheduling these observations.