Submillimeter Continuum Emission in the ρ Ophiuchi Molecular Cloud: Filaments, Arcs, and an Unidentified Far-Infrared Object

Abstract

New wide-field images of the ρ Ophiuchi molecular cloud at 850 and 450 μm obtained with the Submillimeter Common-User Bolometer Array on the James Clerk Maxwell Telescope reveal a wide variety of large-scale features that were previously unknown. Two linear features, each 4' (0.2 pc) in length, extend to the north of the bright emission region containing SM1 and VLA 1623. These features may correspond to the walls of a previously unidentified outflow cavity or the boundary of a photon-dominated region powered by a nearby B star. A previously unidentified source is located in the northeast region of the image. The properties of this source (diameter ~5000 AU, mass ~0.3-1 M) suggest that it is a preprotostellar core. Two arcs of emission are seen in the direction of the northwest extension of the VLA 1623 outflow. The outer arc appears relatively smooth at 850 μm and is estimated to have a mass of ~0.3 M, while the inner arc breaks up into a number of individual clumps, some of which are previously identified protostars.