2015/12/22 by A. Pon, Andy Pon, Doug Johnstone +13
Physics and Astronomy · Chemistry · #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #Molecular Spectroscopy and Structure
paper · pdf · doi:10.1051/0004-6361/201527154
Infrared dark clouds are kinematically complex molecular structures in the interstellar medium that can host sites of massive star formation. We present maps measuring 4 square arcminutes of the 12 CO, 13 CO, and C 18 O J = 3 to 2 lines from selected locations within the C and F (G028.37+00.07 and G034.43+00.24) infrared dark clouds (IRDCs), as well as single pointing observations of the 13 CO and C 18 O J = 2 to 1 lines towards three cores within these clouds. We derive CO gas temperatures throughout the maps and find that CO is significantly frozen out within these IRDCs. We find that the CO depletion tends to be the highest near column density peaks with maximum depletion factors between 5 and 9 in IRDC F and between 16 and 31 in IRDC C. We also detect multiple velocity components and complex kinematic structure in both IRDCs. Therefore, the kinematics of IRDCs seem to point to dynamically evolving structures yielding dense cores with considerable depletion factors.