title: Molecular cloud formation with self-consistent thermal and chemical treatment of the gas
creator: Micic, Milica
subject: 530
subject: 530 Physics
description: Understanding physical and chemical processes that guide the formation and evolution  of giant molecular clouds (GMCs) has important implications for the formation of stars.  GMCs dominantly consist of molecular hydrogen, but there are more than 200 chemical  species of various combinations of carbon, nitrogen and oxygen atoms. Together, these  species control the cooling ability with the thermal and dynamical evolution of the  gas cloud. In order to overcome the restrictions encountered by most previous models  of molecular cloud formation due to the complexity of chemical reaction networks  and its inclusion in hydrodynamical codes, we have implemented detailed treatment  of atomic/molecular cooling and hydrogen chemistry into state-of-art high resolution  hydrodynamical simulations. The main focus of our study is on the influence that  choosing between different cooling functions and turbulent driving has on the formation  and evolution of molecular gas. In that manner, we study the influence of the nature of  the turbulence on the formation of molecular hydrogen by examining both solenoidal  (divergence-free) and compressive (curl-free) turbulent driving. The obtained results  we use to test a simple prescription suggested by Gnedin et al. (2009) for modelling  the influence of unresolved density fluctuations on the H2 formation rate in largescale  simulations of the ISM. We also investigate the properties of the dense clumps  formed within our model of the molecular cloud formation in converging flows and  directly compare the results obtained using the simple, parametrized cooling function  introduced by Koyama & Inutsuka (2002) and used by a number of converging flows  studies with the results of the detailed calculation of the non-equilibrium chemistry  and thermal balance of the gas. Finally, we study C I and CO emission from molecular  clouds in comparison to their column densities and the total column density, as we  look for the way to trace the structure of the cloud.
date: 2013-01-11
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/14315/1/mythesis.pdf
identifier: DOI:10.11588/heidok.00014315
identifier: urn:nbn:de:bsz:16-heidok-143151
identifier:   Micic, Milica  (2013) Molecular cloud formation with self-consistent thermal and chemical treatment of the gas.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/14315/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng