Multiwavelength Signatures of Magnetic Activity from Young Stellar Objects in the LkHα101 Cluster

We describe the results of our multi-wavelength observing campaign on the young stellar objects in the LkHα101 cluster. Our simultaneous X-ray and multifrequency radio observations are unique in providing simultaneous constraints on short-timescale variability at both wavelengths as well as constraints on the thermal or nonthermal nature of radio emission from young stars. Focussing in on radio-emitting objects and the multi-wavelength data obtained for them, we find that multi-frequency radio data indicate nonthermal emission even in objects with infrared evidence for disks. We find radio variability on timescales of decades, days and hours. About half of the objects with X-ray and radio detections were variable at X-ray wavelengths, despite lacking large-scale flares or large variations. Variability appears to be a bigger factor affecting radio emission than X-ray emission. A star with infrared evidence for a disk, [BW88] 3, was observed in the decay phase of radio flare. In this object and another ([BW88] 1), we find an inverse correlation between radio flux and spectral index which contrasts with behavior seen in the Sun and active stars. We interpret this behavior as the repopulation of the hardest energy electrons due to particle acceleration. A radio and X-ray source lacking an infrared counterpart, [BW88] 1, may be near the substellar limit; its radio properties are similar to other cluster members,