Shock-driven synchrotron radio emission from the 2021 outburst of RS Ophiuchi
Abstract
We present low-frequency radio observations of the Galactic symbiotic recurrent nova RS Ophiuchi during its 2021 outburst. The observations were carried out with the upgraded Giant Metrewave Radio Telescope spanning a frequency range of 0.15-1.4 GHz during 23-287 d post the outburst. The average value of the optically thin spectral index is α ~ -0.4 (Fν ∝ να), indicating a non-thermal origin of the radio emission at the observed frequencies. The radio light curves are best represented by shock-driven synchrotron emission, initially absorbed by a clumpy ionized circumbinary medium. We estimate the mass-loss rate of the red giant companion star to be $\dot{M} \sim$ 7.5 × 10-8 M⊙ yr-1 for an assumed stellar wind velocity of 20 km s-1. The 0.15-1.4 GHz radio light curves of the 2021 outburst are systematically brighter than those of the 2006 outburst. Considering similar shock properties between the two outbursts, this is indicative of a relatively higher particle number density in the synchrotron emitting plasma in the current outburst.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2024
- DOI:
- 10.1093/mnras/stae201
- arXiv:
- arXiv:2401.05643
- Bibcode:
- 2024MNRAS.528.5528N
- Keywords:
-
- radiation mechanisms: non-thermal;
- radio continuum: general;
- transients: novae;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Accepted for publication in MNRAS, 5 Figures, 4 Tables