A VLA Survey For Faint Compact Radio Sources in the Orion Nebula Cluster

TL;DR

This survey used the VLA to map faint compact radio sources in the Orion Nebula Cluster, detecting 175 sources and providing models to interpret their emission and implications for protoplanetary disk studies.

Contribution

First comprehensive VLA survey of faint radio sources in the ONC, detecting new sources and modeling their emission for better understanding of protoplanetary disks.

Findings

Detected 175 radio sources, including 26 new detections.

Modeled free-free and dust emission for each source.

Compared fluxes across epochs to analyze variability.

Abstract

We present Karl G. Janksy Very Large Array (VLA) 1.3 cm, 3.6 cm, and 6 cm continuum maps of compact radio sources in the Orion Nebular Cluster. We mosaicked 34 square arcminutes at 1.3 cm, 70 square arcminutes at 3.6 cm and 109 square arcminutes at 6 cm, containing 778 near-infrared detected YSOs and 190 HST-identified proplyds (with significant overlap between those characterizations). We detected radio emission from 175 compact radio sources in the ONC, including 26 sources that were detected for the first time at these wavelengths. For each detected source we fit a simple free-free and dust emission model to characterize the radio emission. We extrapolate the free-free emission spectrum model for each source to ALMA bands to illustrate how these measurements could be used to correctly measure protoplanetary disk dust masses from sub-millimeter flux measurements. Finally, we compare the fluxes measured in this survey with previously measured fluxes for our targets, as well as four separate epochs of 1.3 cm data, to search for and quantify variability of our sources.