Outflows in ρ Ophiuchi as seen with the Spitzer infrared array camera

Abstract

Using the IRAC images from the Spitzer c2d program, we have made a survey of mid-infrared outflows in the ρ Ophiuchi molecular cloud. Extended objects that have prominent emission in IRAC channel 2 (4.5 μm) compared to IRAC channel 1 (3.6 μm) and stand out as green objects in the three-color images (3.6 μm in blue, 4.5 μm in green, 8.0 μm in red) are identified as mid-infrared outflows. As a result, we detected 13 new outflows in the ρ Ophiuchi molecular cloud that have not been previously observed in either the optical or the near-infrared. In addition, at the positions of previously observed HH objects or near-infrared emission, we detected 31 mid-infrared outflows, among which seven correspond to previously observed HH objects and 30 to near-infrared emission. Most of the mid-infrared outflows detected in the ρ Ophiuchi cloud are concentrated in the L1688 dense core region. In combination with the survey results for young stellar objects (YSOs) and millimeter and submillimeter sources, the distribution of mid-infrared outflows in the ρ Ophiuchi molecular complex hints a propagation of star formation in the cloud in the direction from the northwest to the southeast, as suggested by previous studies of the region. © 2009 The American Astronomical Society. All rights reserved.