Jonas Syed (Germany)
syed @ mpia.de
Atomic and molecular cloud formation processes in the ISM
Molecular clouds harbor the birthplaces of stars and form out of the atomic phase of the interstellar medium. To understand cloud formation processes, it is crucial to investigate the relation between atomic and molecular gas. Employing the HI data of the THOR survey (Beuther et al. 2016), we address this by studying the cold neutral medium by means of HI self absorption (HISA) towards giant molecular filaments (Ragan et al. 2014) and comparing our results with molecular gas kinematics. We identify HISA features both with and without a molecular counterpart. The column densities of the cold neutral medium probed by HISA are on the order of 1020 cm−2 while those of molecular hydrogen traced by 13CO are an order of magnitude higher. The column density probability density functions of HISA and HI emission reveal a log-normal shape for most regions, indicative of turbulent motions as the main driver for these structures.
We furthermore aim to characterize giant atomic filaments seen in HI emission that do not show molecular counterparts or signs of active star formation. These filaments might hold important insights into the initial stages of cloud formation processes.
Supervisor: Henrik Beuther (MPIA)