Multiplicity, disks, and jets in the NGC2071 star-forming region

Abstract

We present centimeter (cm) and millimeter (mm) observations of the NGC2071 star-forming region performed with the Very Large Array (VLA) and Combined Array for Research in Millimeter-wave Astronomy (CARMA). We detected counterparts at 3.6cm and 3mm for the previously known sources IRS1, IRS2, IRS3, and VLA 1. All these sources show spectral energy distributions (SEDs) dominated by free-free thermal emission atcm wavelengths and thermal dust emission atmm wavelengths, suggesting that all of them are associated with young stellar objects (YSOs). IRS1 shows a complex morphology at 3.6cm, with changes in the direction of its elongation. We discuss two possible explanations to this morphology: the result of changes in the direction of a jet due to interactions with a dense ambient medium, or that we are actually observing the superposition of two jets arising from two components of a binary system. Higher angular resolution observations at 1.3cm support the second possibility, since a double source is inferred at this wavelength. IRS3 shows a clear jet-like morphology at 3.6cm. Over a timespan of four years, we observed changes in the morphology of this source that we interpret as due to ejection of ionized material in a jet. The emission at 3mm of IRS3 is angularly resolved, with a deconvolved size (FWHM) of 120AU, and seems to be tracing a dusty circumstellar disk perpendicular to the radio jet. An irradiated accretion disk model around an intermediate-mass YSO can account for the observed SED and spatial intensity profile at 3mm, supporting this interpretation. © 2012. The American Astronomical Society. All rights reserved.