Millimetre observations of Gamma-ray bursts at IRAM

Abstract

Since 1997, and following our detection of the first mm after-glow, we have followed-up 70GRBs, mainly with the IRAM’s Plateau de Bure Interferometer, what can be considered as the IRAM Legacy GRB Sample. 66 events were observed at 3 mm, with 19 of them being detected (with another 3 having marginal detections). 32 GRBs were followed up at 1 mm, with 6 of them being detected. Redshifts for the GRB afterglows lie in the range z=0.03-8.3, with measured flux densities (at 3mm) varying between 0.25 and 60mJy (but usually < 1.5 mJy) with first observations taking place around 1-2 days after the GRb. Forward shock emission expleains the observations with the exception of one particular case (GRB 090423 at z= 8.2) for which reverse shock emission is required.