Interpreting a Dwarf Nova Eruption as Magnetic Flare Activity

TL;DR

The paper proposes that radio emissions during a dwarf nova outburst originate from magnetic coronae, similar to active stars, rather than jets, based on flux ratio analysis and implications for mass ejection mechanisms.

Contribution

It introduces a magnetic activity-based explanation for radio emissions in dwarf novae, challenging the jet paradigm and linking stellar magnetic flares to jet launching across systems.

Findings

Radio to X-ray flux ratio in SS Cyg is less than 10^{-5}.

Magnetic activity may be the primary driver of radio emissions during outbursts.

Magnetic flares could be responsible for jet launching in various astrophysical systems.

Abstract

We suggest that the radio emission from the dwarf nova SS Cyg during outburst comes from magnetic activity that formed a corona (similar to coronae found in magnetically active stars), rather than from jets. We base our claim on the recent results of Laor & Behar, who found that when the ratio between radio and X-ray flux of accretion disks in radio-quiet quasars is as in active stars, Lr/Lx=10^{-5}, then most of the radio emission comes from coronae. Using observations from the literature we find that for SS Cyg during outburst Lr/Lx<10^{-5}. This does not mean jets are not launched during outbursts. On the contrary, if the magnetic activity in erupting accreting disks is similar to that in stars, then mass ejection, e.g., as in coronal mass ejection, is expected. Hence magnetic flares similar to those in active stars might be the main mechanism for launching jets in a variety of systems, from young stellar objects to massive black holes.