  Using the IRAC images from the Spitzer c2d program, we have made a survey of
mid-infrared outflows in the rho Ophiuchi molecular cloud. Extended objects
that have prominent emission in IRAC channel 2 (4.5 micron) compared to IRAC
channel 1 (3.6 micron) and stand out as green objects in the three-color images
(3.6 micron in blue, 4.5 micron in green, 8.0 micron in red) are identified as
mid-infrared outflows. As a result, we detected 13 new outflows in the rho
Ophiuchi molecular cloud that have not been previously observed in optical or
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 rho Ophiuchi cloud
are concentrated in the L1688 dense core region. In combination with the survey
results for Young Stellar Objects (YSOs) and millimeter and sub-millimeter
sources, the distribution of mid-infrared outflows in the rho 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.
