The Fast Radio Burst FRB 20201124A in a star forming region: constraints\n to the progenitor and multiwavelength counterparts

Abstract

We present the results of a multiwavelength campaign of FRB 20201124A, the\nthird closest repeating fast radio burst recently localized in a nearby\n(z=0.0978) galaxy. Deep VLA observations led to the detection of quiescent\nradio emission, also marginally visible in X-rays with Chandra. Imaging at 22\nGHz allowed us to resolve the source on a scale of $\\gtrsim$ 1 arcsec and\nlocate it at the position of the FRB, within an error of 0.2 arcsec. EVN and\ne-MERLIN observations sampled small angular scales, from 2 to 100 mas,\nproviding tight upper limits on the presence of a compact source and evidence\nfor diffuse radio emission. We argue that this emission is associated with\nenhanced star formation activity in the proximity of the FRB, corresponding to\na star formation rate of $\\approx 10\\ {\\rm M}_\\odot {\\rm yr}^{-1}$. The surface\nstar formation rate at the location of FRB 20201124A is two orders of magnitude\nlarger than typically observed in other precisely localized FRBs. Such a high\nSFR is indicative of this FRB source being a new-born magnetar produced from a\nSN explosion of a massive star progenitor. Upper limits to the X-ray\ncounterparts of 49 radio bursts observed in our simultaneous FAST, SRT and\nChandra campaign are consistent with a magnetar scenario.\n