Letter to the Editor

The fast radio burst FRB 20201124A in a star-forming region: Constraints to the progenitor and multiwavelength counterparts

¹ INAF – Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere 100, 00133 Rome, Italy
e-mail: luigi.piro@inaf.it
² Department of Astronomy, University of Maryland, College Park, MD 20742-4111, USA
³ Astrophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771, USA
⁴ Department of Physics, The George Washington University, 725 21st Street NW, Washington, DC 20052, USA
⁵ Astronomy, Physics, and Statistics Institute of Sciences (APSIS), The George Washington University, Washington, DC 20052, USA
⁶ INAF – Istituto di Radioastronomia, Via Gobetti 101, 40129 Bologna, Italy
⁷ Istituto Nazionale di Ricerca Metrologica (INRiM) – Strada delle Cacce 91, 10135 Torino, Italy
⁸ Department of Physics and Astronomy, University of Nevada, 89154 Las Vegas, NV, USA
⁹ INAF – Osservatorio Astronomico di Cagliari, via della Scienza 5, 09047 Selargius (CA), Italy
¹⁰ Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, PR China
¹¹ National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, PR China
¹² Department of Physics, Università di Cagliari, S.P. Monserrato-Sestu km 0,700, 09042 Monserrato (CA), Italy

Received: 29 July 2021
Accepted: 8 November 2021

Abstract

We present the results of a multiwavelength campaign targeting FRB 20201124A, the third closest repeating fast radio burst (FRB), which was recently localized in a nearby (z = 0.0978) galaxy. Deep VLA observations led to the detection of quiescent radio emission, which was also marginally visible in X-rays with Chandra. Imaging at 22 GHz allowed us to resolve the source on a scale of ≳1″ and locate it at the position of the FRB, within an error of 0.2″. The 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 (SFR) of ≈10 M_⊙ yr⁻¹. The surface SFR at the location of FRB 20201124A is two orders of magnitude larger than what is typically observed in other precisely localized FRBs. Such a high SFR is indicative of this FRB source being a newborn magnetar produced from a supernova 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.