Characterizing the radio continuum nature of sources in the massive star-forming region W75N (B)

Abstract

The massive star-forming region W75N~(B) is thought to host a cluster of massive protostars (VLA~1, VLA~2, and VLA~3) undergoing different evolutionary stages. In this work, we present radio continuum data with the highest sensitivity and angular resolution obtained to date in this region, using the VLA-A and covering a wide range of frequencies (4-48~GHz), which allowed us to study the morphology and the nature of the emission of the different radio continuum sources. We also performed complementary studies with multi-epoch VLA data and ALMA archive data at 1.3 mm wavelength. We find that VLA~1 is driving a thermal radio jet at scales of $\approx$0.1 arcsec ($\approx$130 au), but also shows signs of an incipient hyper-compact HII region at scales of $\lesssim$ 1 arcsec ($\lesssim$ 1300~au). VLA~3 is also driving a thermal radio jet at scales of a few tenths of arcsec (few hundred of au). We conclude that this jet is shock-exciting the radio continuum sources Bc and VLA~4 (obscured HH objects), which show proper motions moving outward from VLA~3 at velocities of $\approx$112--118~km/s. We have also detected three new weak radio continuum sources, two of them associated with millimeter continuum cores observed with ALMA, suggesting that these two sources are also embedded YSOs in this massive star-forming region.

14 pages, 7 figures. Accepted for publication in MNRAS

References in corpus (5)

• Search for ionized jets towards high-mass young stellar objects
• Binary system and jet precession and expansion in G35.20-0.74N
• Anatomy of the internal bow shocks in the IRAS 04166+2706 protostellar jet
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Cited by in corpus (4)

• Protostellar Interferometric Line Survey of the Cygnus X region (PILS-Cygnus) -- First results: observations of CygX-N30
• A global view on star formation: The GLOSTAR Galactic plane survey III. 6.7 GHz methanol maser survey in Cygnus X
• Monitoring of the polarized $H_{2}O$ maser emission around the massive protostars W75N(B)-VLA1 and W75N(B)-VLA2
• Surveys of Clumps, Cores, and Condensations in the Cygnus X: II. Radio Properties of the Massive Dense Cores