The JCMT Transient Survey: An Extraordinary Submillimetre Flare in the T Tauri Binary System JW 566

Abstract

The binary T Tauri system JW 566 in the Orion Molecular Cloud underwent an energetic, short-lived flare observed at submillimetre wavelengths by the SCUBA-2 instrument on 26 November 2016 (UT). The emission faded by nearly 50% during the 31 minute integration. The simultaneous source fluxes averaged over the observation are 500 +/- 107 mJy/beam at 450 microns and 466 +/- 47 mJy/beam at 850 microns. The 850 micron flux corresponds to a radio luminosity of $L_{\hat{I}}½=8\times 10^{19}$ erg/s/Hz, approximately one order of magnitude brighter (in terms of $\hat{I}½L_{\hat{I}}½$) than that of a flare of the young star GMR-A, detected in Orion in 2003 at 3mm. The event may be the most luminous known flare associated with a young stellar object and is also the first coronal flare discovered at sub-mm wavelengths. The spectral index between 450 microns and 850 microns of $\hat{I}\pm =0.11$ is broadly consistent with non-thermal emission. The brightness temperature was in excess of $6\times 10^4$ K. We interpret this event to be a magnetic reconnection that energised charged particles to emit gyrosynchrotron/synchrotron radiation.

Accepted in ApJ. 16 pages (single column), 6 figures