Millimeter multiplicity in DR21(OH): outflows, molecular cores and envelopes

TL;DR

This study uses high-resolution millimeter observations to identify new compact sources, outflows, and molecular emissions in the DR21(OH) star-forming region, revealing complex structures and outflow interactions.

Contribution

It reports the discovery of a new cluster of compact millimeter sources and detailed molecular outflow structures in DR21(OH), advancing understanding of massive star formation processes.

Findings

Detected about ten new compact millimeter sources with masses 5-24 M$_$

Identified multiple collimated outflows traced by CO, SiO, H$_2$CO, and CH$_3$OH emissions

Linked a specific maser outflow to a millimeter source SMA4.

Abstract

We present sensitive high angular resolution ($\sim$ 1$"$) millimeter continuum and line observations from the massive star forming region DR21(OH) located in the Cygnus X molecular cloud. Within the well-known dusty MM1-2 molecular cores, we report the detection of a new cluster of about ten compact continuum millimeter sources with masses between 5 and 24 M$_\odot$, and sizes of a few thousands of astronomical units. These objects are likely to be large dusty envelopes surrounding massive protostars, some of them most probably driving several of the outflows that emanate from this region. Additionally, we report the detection of strong millimeter emission of formaldehyde (H$_2$CO) and methanol (CH$_3$OH) near 218 GHz as well as compact emission from the typical outflow tracers carbon monoxide and silicon monoxide (CO and SiO) toward this massive star-forming region. The H$_2$CO and CH$_3$OH emission is luminous ($\sim$ 10$^{-4}$ L$_{\odot}$), well resolved, and found along the collimated methanol maser outflow first identified at centimeter wavelengths and in the sources SMA6 and SMA7. Our observations suggest that this maser outflow might be energized by a millimeter source called SMA4 located in the MM2 dusty core. The CO and SiO emission traces some other collimated outflows that emanate from MM1-2 cores, and are not related with the low velocity maser outflow.