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

L. Piro, G. Bruni, E. Troja, B. O'Connor, F. Panessa, R. Ricci, B. Zhang, M. Burgay, S. Dichiara, K. J. Lee, S. Lotti, J. R. Niu, M. Pilia, A. Possenti, M. Trudu, H. Xu, W. W. Zhu, A. S. Kutyrev, S. Veilleux

Published 2021-07-29Version 1

We present the results of a multiwavelength campaign of FRB20201124A, the second closest repeating fast radio burst recently localized in a nearby (z=0.0978) galaxy. Deep VLA observations led to the detection of a quiescent radio emission, also marginally visible in X-rays with Chandra. Imaging at 22 GHz allowed us to resolve the source on a scale of $\gtrsim 1$ arcsec in a direction tangential to the center of the host galaxy and locate it at the position of the FRB, within an error of $0.2$ arcsec. EVN and e-MERLIN observations sampled small angular scales, from 2 to 100 mas, providing tight upper limits on the presence of a compact source and evidence for diffuse radio emission. We argue that this emission is associated with enhanced star formation activity in the proximity of the FRB, corresponding to a star formation rate of $\approx 10\ {\rm M}_\odot {\rm yr}^{-1}$. The surface star formation rate at the location of FRB20201124A is two orders of magnitude larger than typically observed in other precisely localized FRBs. Such a high SFR is indicative of this FRB source being a new-born magnetar produced from a SN explosion of a massive star progenitor. Upper limits to the X-ray counterparts of 49 radio bursts observed in our simultaneous FAST, SRT and Chandra campaign are consistent with a magnetar scenario.