The JCMT Transient Survey: Detection of YSO flares

Bhavana Lalchand^1*, Wen-Ping Chen¹

¹Graduate Institute of Astronomy, National Central University, Taoyuan city, Taiwan

* Presenter:Bhavana Lalchand, email:bhavana_lalchand@gm.astro.ncu.edu.tw

Observations of temporal brightness variability provide physical insights to the stellar structure, e.g. the convective/dynamo mechanism. Moreover, during the earliest phase of stellar assembly, i.e., when a protostar is vigorously accreting from circumstellar material, sporadic brightening events are expected. Yet such protostellar flares have not been well characterized because of the enshrouding dusty envelope, rendering optical/infrared detection difficult. Here we report the dedicated program to monitor, on a monthly cadence, the protostellar transient phenomena, with the James Clerk Maxwell Telescope (JCMT) using the SCUBA-2 array bolometer. This JCMT Transient Survey, the first time-domain sub-mm program, is being carried out since 2015 for eight nearby star-forming regions including regions such as IC348, NGC1333, Ophiuchus Core, among others. We have successfully detected 182 known protostars (Class 0) and 800 disk sources (T Tauri stars), and so far discovered an extraordinary sub-mm flare by JW566, a T-Tauri binary undergoing magnetic reconnection that energized charged particles to emit gyro-synchrotron or synchrotron radiation. We present the project concept, progress thus far, the detection algorithm for sub-mm brightening events, and how our observational statistics would reconcile with theoretical models.

Keywords: Convective/dynamo mechanism, Sporadic brightening events, JCMT SCUBA-2, Star forming regions, Gyro-synchrotron or synchrotron radiation