EPoS Contribution
EPoS Contribution
The Orion Radio All-Stars: new perspectives in stellar radio astronomy

Jan Forbrich
U Vienna/CfA, Vienna, AT
In recent years, the sensitivity upgrades of both the NRAO Karl G. Jansky Very Large Array (VLA) and the NRAO Very Long Baseline Array (VLBA) have provided us with a much improved perspective on stellar centimeter radio emission. This is particularly true for young stellar objects where both radio and X-ray emission trace high-energy processes in the innermost vicinities of these objects. I will present first results of a deep C-band radio survey of the Orion Nebula Cluster (ONC), using the VLA and the VLBA, where additionally almost 24h of VLA observations were accompanied by simultaneous X-ray observations with Chandra. The VLA data have unveiled 556 compact radio sources in the ONC, a sevenfold increase over previous studies, as well as complex emission structures on a wide range of spatial scales, including the proplyds. The high sensitivity of the radio observations allow us to better disentangle thermal and nonthermal radio emission by assessing spectral indices, polarization, and variability. Combined with simultaneous radio-X-ray time domain information and comprehensive astrometric VLBA follow-up observations (not least as a decisive criterion of nonthermal emission), this project is providing unprecedented constraints on the magnetospheric activity of young stellar objects across a mass range from M dwarfs to massive stars and a new perspective on the impact of the massive Trapezium stars on their environment.
Caption: VLA view of the inner ONC, a small fraction of the survey field. These images show wideband continuum data with a reference frequency of 6.1 GHz (C-band). The locations of the main Trapezium stars Theta1 Ori A-D are marked with star symbols.
V. Rivilla, Arcetri, IT
K. Menten, MPIfR, DE
M. Reid, CfA, US
C. Chandler, NRAO, US
U. Rau, NRAO, US
S. Bhatnagar, NRAO, US
S.J. Wolk, CfA, US
S. Meingast, Vienna, US
Suggested Session: From Low- to High-Mass Star Formation