Continued radio observations of the persistent radio source associated with FRB20190520B provides insights into its origin

TL;DR

This study presents new radio observations of the persistent source linked to FRB 20190520B, revealing brightness variability, spectral break evidence, and constraints on the progenitor's age, challenging existing models.

Contribution

It provides the first low-frequency observations of the source, identifies spectral absorption features, and constrains the magnetar progenitor's age, advancing understanding of FRB origins.

Findings

Observed gradual decay and variability in the PRS brightness.

Detected a spectral break indicating absorption processes.

Constrained the magnetar progenitor's age to approximately 52 years.

Abstract

Follow-up studies of persistent emission from fast radio burst (FRB) sources are critical for understanding their elusive emission mechanisms and the nature of their progenitors. This work presents new observations of the persistent radio source (PRS) associated with FRB 20190520B. We observe a gradual decay in the PRS brightness, which is punctuated by periods of brightening and dimming at both 1.5 and 3 GHz. Furthermore, our low-frequency ($<1$ GHz) observations--the first for this source--reveal evidence of a spectral break, which can be attributed to absorption processes. Interpreted within the framework of the magnetar wind nebula model, our data constrain the age of the magnetar progenitor to $52^{+16}_{-10}$ yr, broadly consistent with previous work. Assuming the observed 1.5 GHz variability is driven by scintillation, we discuss the constraints on the size of the persistent source. The observations presented here challenge the predictions of the previously published best-fit hypernebula model for this source.