Universität zu Köln

Brugaletta, Vittoria ORCID: 0000-0003-1221-8771, Walch, Stefanie ORCID: 0000-0001-6941-7638, Naab, Thorsten ORCID: 0000-0002-7314-2558, Rathjen, Tim-Eric ORCID: 0000-0002-8228-3715, Girichidis, Philipp ORCID: 0000-0002-9300-9914, Seifried, Daniel ORCID: 0000-0002-0368-9160, Nürnberger, Pierre Colin ORCID: 0000-0003-4384-3115, Wünsch, Richard ORCID: 0000-0003-1848-8967, Glover, Simon C O ORCID: 0000-0001-6708-1317, Pal, Sanjit ORCID: 0009-0009-5968-5482 and Wasmuth, Lukas (2025). SILCC – IX. The multiphase interstellar medium at low metallicity. Monthly Notices of the Royal Astronomical Society, 543 (4). pp. 4286-4311. Oxford University Press. ISSN 0035-8711

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Abstract

The gas-phase metallicity affects heating and cooling processes in the star-forming galactic interstellar medium (ISM) as well as ionizing luminosities, wind strengths, and lifetimes of massive stars. To investigate its impact, we conduct magnetohydrodynamic simulations of the ISM using the flash code as part of the silcc project. The simulations assume a gas surface density of 10 M$_\odot$ pc$^{-2}$ and span metallicities from 1/50 to 1 Z$_\odot$. We include non-equilibrium thermochemistry, a space- and time-variable far-UV background and cosmic ray ionization rate, metal-dependent stellar tracks, the formation of H ii regions, stellar winds, type II supernovae, and cosmic ray injection and transport. With the metallicity decreasing over the investigated range, the star formation rate decreases by more than a factor of 10, the mass fraction of cold gas decreases from 60 per cent to 2.3 per cent, while the volume filling fraction of the warm gas increases from 20 per cent to 80 per cent. Furthermore, the fraction of H$_\mathrm{2}$ in the densest regions drops by a factor of 4, and the dense ISM fragments into approximately five times fewer structures at the lowest metallicity. Outflow mass loading factors remain largely unchanged, with values close to unity, except for a significant decline at the lowest metallicity. Including the major processes that regulate ISM properties, this study highlights the strong impact of gas phase metallicity on the star-forming ISM.

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 Rathjen, Tim-Eric UNSPECIFIED https://orcid.org/0000-0002-8228-3715 UNSPECIFIED Girichidis, Philipp UNSPECIFIED https://orcid.org/0000-0002-9300-9914 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 Pal, Sanjit UNSPECIFIED https://orcid.org/0009-0009-5968-5482 UNSPECIFIED Wasmuth, Lukas UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-811301
Identification Number:	10.1093/mnras/staf1713
Journal or Publication Title:	Monthly Notices of the Royal Astronomical Society
Volume:	543
Number:	4
Page Range:	pp. 4286-4311
Number of Pages:	26
Date:	16 October 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
Uncontrolled Keywords:	Keywords Language methods ; numerical ; ISM: abundances ; ISM: jets and outflows ; ISM: kinematics and dynamics ; ISM: structure ; galaxies: ISM English
['eprint_fieldname_oa_funders' not defined]:	Publikationsfonds UzK
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/81130