SO Webloquio:The Orion Radio All-Stars: new insights into YSO radio emission, using the VLA, VLBA, and ALMA

With significant new observing capabilities, centimeter-wavelength radio astronomy is currently in a renaissance leading up to the advent of the Square Kilometre Array (SKA), highlighting new opportunities and also technical challenges. The sensitivity upgrades of both the NRAO Very Large Array (VLA) and the Very Long Baseline Array (VLBA) have begun to provide us with a much improved perspective on stellar centimeter radio emission, particularly concerning young stellar objects (YSOs) and ultracool dwarfs. For the first time we now have systematic access to the radio time domain and new information to disentangle thermal and nonthermal emission. I will mainly present the Orion Radio All-Stars, an ongoing project targeting the Orion Nebula Cluster (ONC) with the VLA, VLBA, and ALMA. With simultaneous radio-X-ray time domain information (Chandra), this project is providing first constraints on YSO radio flares and their relation with X-ray flares, as well as improved constraints on the overall high-energy irradiation of their surroundings, including protoplanetary disks. Our astrometric follow-up of all identified VLA targets in Orion is the largest VLBA survey for YSO emission to date. Other than providing a nonthermal census, I will additionally discuss the use of the VLBA for precision stellar astrometry in the Gaia era. I will conclude with a first look at variable millimeter continuum emission in the inner ONC, targeting synchrotron flares in this new window on high-energy processes in YSOs.

30/07/2020 - 12:30
Jan Forbrich
University of Hertfordshire, UK