Universität zu Köln

Joshi, P. R., Walch, S., Seifried, D., Glover, S. C. O., Clarke, S. D. and Weis, M. (2019). On the resolution requirements for modelling molecular gas formation in solar neighbourhood conditions. Mon. Not. Roy. Astron. Soc., 484 (2). S. 1735 - 1756. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

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Abstract

The formation of molecular hydrogen (H-2) and carbon monoxide (CO) is sensitive to the volume and column density distribution of the turbulent interstellar medium. In this paper, we study H-2 and CO formation in a large set of hydrodynamical simulations of periodic boxes with driven supersonic turbulence, as well as in colliding flows with the FLASH code. The simulations include a non-equilibrium chemistry network, gas self-gravity, and diffuse radiative transfer. We investigate the spatial resolution required to obtain a converged H-2 and CO mass fraction and formation history. From the numerical tests we find that H-2 converges at a spatial resolution of less than or similar to 0.2 pc, while the required resolution for CO convergence is less than or similar to 0.04 pc in gas with solar metallicity that is subject to a solar neighbourhood interstellar radiation field. We derive two critical conditions from our numerical results: the simulation has to at least resolve the densities at which (1) the molecule formation time in each cell in the computational domain is equal to the dissociation time and (2) the formation time is equal to the typical cell crossing time. For both 2 and CO, the second criterion is more restrictive. The formulae we derive can be used to check whether molecule formation is converged in any given simulation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Joshi, P. R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Walch, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Seifried, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Glover, S. C. O. UNSPECIFIED UNSPECIFIED UNSPECIFIED Clarke, S. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Weis, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-152680
DOI:	10.1093/mnras/stz052
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	484
Number:	2
Page Range:	S. 1735 - 1756
Date:	2019
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language INTERSTELLAR ATOMIC-HYDROGEN; SUPERNOVA-DRIVEN ISM; CLOUD FORMATION; STAR-FORMATION; CHEMICAL EVOLUTION; SPATIAL-RESOLUTION; MAGNETIC-FIELDS; SILCC PROJECT; TURBULENCE; IMPACT Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15268