Wednesday 10 Feb 2021: Molecular clouds: linking simulations and observations
Daniel Seifried -
Remote seminar 14:00-15:00
In my talk I will present simulations of molecular cloud formation in galactic disks within the SILCC-Zoom collaboration. The simulations include a detailed chemical network for H_2 and CO formation and thus provide a unique tool to discuss important aspects of molecular cloud formation: the (1) chemo-dynamical evolution and (2) the comparison with actual observations by means of synthetic observations. I will show that molecular clouds can be out of chemical equilibrium which provides a huge challenge for numerical simulations. I will also discuss how the complex filamentary structure of these molecular clouds can affect their interaction with stellar feedback like supernova but also the emission of e.g. the CO(1-0) and the HI 21 cm line. Furthermore, in view of the increasing number of polarisation observations, I present the first self-consistent synthetic dust polarisation maps created with the POLARIS code. I will show that observed polarisation vectors in clouds probe the real field structure with an accuracy of about 5 degree and that the long-debated de-polarisation on clouds scales results from strongly tangled field lines rather than inefficient grain alignment. Finally, I will shed light on the origin of the alignment of magnetic fields and density structures as recently observed by e.g. the Planck and BlastPol collaboration.