University of Hertfordshire

From the same journal

From the same journal

By the same authors

A VLBA Survey of radio stars in the Orion Nebula Cluster: I. The nonthermal radio population

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  • 2011.09329v1

    Accepted author manuscript, 189 KB, PDF document

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Original languageEnglish
Article number23
JournalThe Astrophysical Journal
Publication statusPublished - 4 Jan 2021


We present first results of a four-epoch VLBA survey for nonthermal emission toward all 556 compact radio sources previously identified in a deep VLA survey of the Orion Nebula Cluster (ONC). We identify VLBA counterparts toward an unprecedented 123 sources. Of these, 41 do not have X-ray counterparts, of which 34 also do not display near-infrared counterparts. Since these cannot be explained by extragalactic background sources, this suggests a component of the ONC population of young stellar objects that are too deeply embedded for even X-rays to be detectable. We find pervasive variability and detect even most of the highest-S/N sources in only one out of four epochs. Neither a negative spectral index nor extreme variability in the VLA data is a good predictor of a VLBA detection.


Funding Information: We thank the anonymous referee for helpful and constructive comments that lead to an improved presentation of our results. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Publisher Copyright: © 2021. The American Astronomical Society.

ID: 23020971