The Structure of Dark Molecular Gas in the Galaxy -- II. Physical State of "CO-Dark" Gas in the Perseus Arm

Michael P. Busch, Ronald J. Allen, Philip D. Engelke +3

We report the results from a new, highly sensitive ($\Delta T_{mb}\sim 3$mK) survey for thermal OH emission at 1665 and 1667 MHz over a dense, 9 x 9-pixel grid covering a $1°$ x $1°$ p…