TITLE: GCN CIRCULAR NUMBER: 24978 SUBJECT: GRB 190530A: Observation of the afterglow by NOEMA DATE: 19/07/04 15:22:54 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), M. Bremer (IRAM), S. Schulze (Weizmann), C. C. Thoene, D. A. Kann, L. Izzo, M. Blazek, K. Bensch (all HETH/IAA-CSIC), D. A. Perley (LJMU), S. Martin (ALMA), I. de Gregorio-Monsalvo (ESO), M. Michalowski (AOI-AMU), R. Sanchez-Ramirez (INAF-IAPS), D. B. Malesani (DTU Space) report: We observed the field of the bright GRB 190530A (Fermi team GCN 24676) with NOEMA, at wavelengths between 76 and 150 GHz in 4 epochs, ranging between 31 May 2019, at 14:29 UT (1.17 days after the burst) and 15 June 2019, at 20:54 UT (16.44 days after the burst). The afterglow (discovered in the optical by Lipunov et al. GCN 24680) was detected on the first epoch with a flux density of 1.0 mJy at 92 GHz. At this time the peak frequency was located close to this observed frequency. In the subsequent epochs the peak frequency of the synchrotron spectrum was bluewards of the 76 GHz frequency band and the source declined steadily in flux density until it was no longer detected in our latest observation, which had an r.m.s of 0.066 mJy at the 92 GHz band.