HH 175: A Giant HH Flow Emanating From A Multiple Protostar
  HH 175 is an isolated Herbig-Haro object seen towards the B35 cloud in the
lambda Ori region. We use deep Subaru 8m interference filter images and Spitzer
images to show that HH 175 is a terminal shock in a large collimated outflow
from the nearby embedded source IRAS 05417+0907. The body of the eastern
outflow lobe is hidden by a dense ridge of gas. The western outflow breaks out
of the front of the cometary-shaped B35 cloud, carrying cloud fragments along,
which are optically visible due to photoionization by the massive lambda Ori
stars. The total extent of the bipolar outflow is 13.7 arcmin, which at the
adopted distance of 415 pc corresponds to a projected dimension of 1.65 pc. The
embedded source IRAS 05417+0907 is located on the flow axis approximately
midway between the two lobes, and near-infrared images show it to be a multiple
system of 6 sources, with a total luminosity of 31 Lsun. Millimeter maps in CO,
13CO, and C18O show that the B35 cloud is highly structured with multiple
cores, of which the one that spawned IRAS 05417+0907 is located at the apex of
B35. It is likely that the embedded source is the result of compression by an
ionization-shock front driven by the lambda Ori OB stars.
