Sensitive CO(1-0) Survey in Pegasus-Pisces Reduces CO-Dark Gas Inventory
  by Factor of Two
  We conducted high-sensitivity, high-velocity resolution CO(1-0) observations
in a region containing a portion of the diffuse molecular cloud MBM 53 to
determine whether weak CO emission was present. The results of our observations
increase the amount of CO-detectable molecular gas in the region by a factor of
two. The increased molecular mass for the cloud, if applicable to the molecular
clouds in the entire Pegasus-Pisces region, decreases the dark molecular gas
content from 58% of the total H2 mass to ~ 30%. If the results for MBM53 are
applicable to other diffuse clouds, then the fraction of dark gas directly
detectable via sensitive CO(1-0) observations in diffuse molecular clouds is
similar to that predicted by models for Giant Molecular Clouds.
