Universität zu Köln

Brugaletta, Vittoria ORCID: 0000-0003-1221-8771, Walch, Stefanie ORCID: 0000-0001-6941-7638, Naab, Thorsten ORCID: 0000-0002-7314-2558, Girichidis, Philipp ORCID: 0000-0002-9300-9914, Rathjen, Tim-Eric ORCID: 0000-0002-8228-3715, Seifried, Daniel ORCID: 0000-0002-0368-9160, Nürnberger, Pierre Colin ORCID: 0000-0003-4384-3115, Wünsch, Richard ORCID: 0000-0003-1848-8967 and Glover, Simon C O ORCID: 0000-0001-6708-1317 (2025). The impact of cosmic-ray heating on the cooling of the low-metallicity interstellar medium. Monthly Notices of the Royal Astronomical Society, 537 (1). pp. 482-499. Oxford University Press. ISSN 0035-8711

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Abstract

Low-metallicity environments are subject to inefficient cooling. They also have low dust-to-gas ratios and therefore less efficient photoelectric (PE) heating than in solar-neighbourhood conditions, where PE heating is one of the most important heating processes in the warm neutral interstellar medium (ISM). We perform magnetohydrodynamic simulations of stratified ISM patches with a gas metallicity of 0.02 Z$_\odot$ as part of the SILCC project. The simulations include non-equilibrium chemistry, heating, and cooling of the low-temperature ISM as well as anisotropic cosmic-ray (CR) transport, and stellar tracks. We include stellar feedback in the form of far-ultraviolet and ionizing (FUV and extreme ultraviolet, EUV) radiation, massive star winds, supernovae, and CR injection. From the local CR energy density, we compute a CR heating rate that is variable in space and time. In this way, we can compare the relative impact of PE and CR heating on the metal-poor ISM and find that CR heating can dominate over PE heating. Models with a uniform CR ionization rate of $\zeta$ = 3 $\times$ 10$^{-17}$ s$^{-1}$ suppress or severely delay star formation, since they provide a larger amount of energy to the ISM due to CR heating. Models with a variable CR ionization rate form stars predominantly in pristine regions with low PE heating and CR ionization rates where the metal-poor gas is able to cool efficiently. Because of the low metallicity, the amount of formed stars in all runs is not enough to trigger outflows of gas from the mid-plane.

Item Type:	Article
Creators:	Creators Email ORCID ORCID Put Code Brugaletta, Vittoria UNSPECIFIED https://orcid.org/0000-0003-1221-8771 UNSPECIFIED Walch, Stefanie UNSPECIFIED https://orcid.org/0000-0001-6941-7638 UNSPECIFIED Naab, Thorsten UNSPECIFIED https://orcid.org/0000-0002-7314-2558 UNSPECIFIED Girichidis, Philipp UNSPECIFIED https://orcid.org/0000-0002-9300-9914 UNSPECIFIED Rathjen, Tim-Eric UNSPECIFIED https://orcid.org/0000-0002-8228-3715 UNSPECIFIED Seifried, Daniel UNSPECIFIED https://orcid.org/0000-0002-0368-9160 UNSPECIFIED Nürnberger, Pierre Colin UNSPECIFIED https://orcid.org/0000-0003-4384-3115 UNSPECIFIED Wünsch, Richard UNSPECIFIED https://orcid.org/0000-0003-1848-8967 UNSPECIFIED Glover, Simon C O UNSPECIFIED https://orcid.org/0000-0001-6708-1317 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-791583
Identification Number:	10.1093/mnras/staf039
Journal or Publication Title:	Monthly Notices of the Royal Astronomical Society
Volume:	537
Number:	1
Page Range:	pp. 482-499
Number of Pages:	18
Date:	15 January 2025
Publisher:	Oxford University Press
ISSN:	0035-8711
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics I
Subjects:	Physics
['eprint_fieldname_oa_funders' not defined]:	Publikationsfonds UzK
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/79158