Surveys of Clumps, Cores, and Condensations in the Cygnus X: II. Radio Properties of the Massive Dense Cores

TL;DR

This study uses high-resolution radio observations to detect and analyze radio emissions from 47 massive dense cores in Cygnus X, revealing that most radio sources are associated with young stellar objects and their evolution.

Contribution

It provides new high-resolution radio data on MDCs in Cygnus X, identifying 64 radio sources and characterizing their emission mechanisms and evolutionary stages.

Findings

Most radio sources are weak, compact, and associated with dust condensations.

Radio luminosity increases with the evolutionary stage of MDCs.

Majority of sources are ionized jets or winds from massive young stellar objects.

Abstract

We have carried out a high-sensitivity and high-resolution radio continuum study towards a sample of 47 massive dense cores (MDCs) in the Cygnus X star-forming complex using the Karl G. Jansky Very Large Array, aiming to detect and characterize the radio emission associated with star-forming activities down to ~0.01 pc scales. We have detected 64 radio sources within or closely around the full width at half-maximum (FWHM) of the MDCs, of which 37 are reported for the first time. The majority of the detected radio sources are associated with dust condensations embedded within the MDCs, and they are mostly weak and compact. We are able to build spectral energy distributions for 8 sources. Two of them indicate non-thermal emission and the other six indicate thermal free-free emission. We have determined that most of the radio sources are ionized jets or winds originating from massive young stellar objects, whereas only a few sources are likely to be ultra-compact HII regions. Further quantitative analyses indicate that the radio luminosity of the detected radio sources increases along the evolution path of the MDCs.