T CrB: Radio Observations During the 2016--2017 "Super-Active" State

TL;DR

This paper reports radio observations of T Coronae Borealis during its 2016-2017 super-active state, revealing increased emission and ionization likely due to higher accretion rates, with thermal bremsstrahlung emission dominating.

Contribution

First detailed radio study of T CrB during a super-active state, linking increased radio emission to enhanced ionization and accretion activity.

Findings

Radio emission increased during the active state

Spectral energy distribution consistent with thermal bremsstrahlung

Radio photosphere located outside the binary system

Abstract

We obtained radio observations of the symbiotic binary and known recurrent nova T Coronae Borealis following a period of increased activity in the optical and X-ray bands. A comparison of our observations with those made prior to 2015 indicates that the system is in a state of higher emission in the radio as well. The spectral energy distributions are consistent with optically thick thermal bremsstrahlung emission from a photoionized source. Our observations indicate that the system was in a state of increased ionization in the companion wind, possibly driven by an increase in accretion rate, with the radio photosphere located well outside the binary system.