Universität zu Köln

Rathjen, Tim-Eric ORCID: 0000-0002-8228-3715, Walch, Stefanie ORCID: 0000-0001-6941-7638, Naab, Thorsten ORCID: 0000-0002-7314-2558, Nürnberger, Pierre ORCID: 0000-0003-4384-3115, Wünsch, Richard ORCID: 0000-0003-1848-8967, Seifried, Daniel ORCID: 0000-0002-0368-9160 and Glover, Simon C O ORCID: 0000-0001-6708-1317 (2025). SILCC – VIII. The impact of far-ultraviolet radiation on star formation and the interstellar medium. Monthly Notices of the Royal Astronomical Society, 540 (2). pp. 1462-1490. Oxford University Press. ISSN 0035-8711

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Abstract

We present magnetohydrodynamic simulations of star formation in the multiphase interstellar medium (ISM) to quantify the impact of non-ionizing far-ultraviolet (FUV) radiation within the Silcc Project simulation framework. Our study incorporates the radiative transfer of ionizing radiation and self-consistent modelling of variable FUV radiation from star clusters, advancing beyond previous studies using static or simplified FUV fields. This enables a more accurate capture of the dynamic interaction between radiation and the evolving ISM alongside other stellar feedback channels. The interstellar radiation field (ISRF) near young star clusters can reach $G_0 \approx 10^4$ (in Habing units), far exceeding the solar neighbourhood value of $G_0 = 1.7$. Despite these high intensities, FUV radiation minimally impacts the integrated star formation rate compared to ionizing radiation, stellar winds, and supernovae. A slight reduction in star formation burstiness is linked to increased photoelectric (PE) heating efficiency by the variable FUV field. Dust near star-forming regions can be heated up to 60 K via the PE effect, with a broad temperature distribution. PE heating rates in variable FUV models exhibit higher peaks but lower averages than static ISRF models. Simulations under solar neighbourhood conditions without stellar winds or ionizing radiation but with supernovae yield unexpectedly high star formation rates of $\sim 0.1~\mathrm{M_\odot ~yr^{-1}~kpc^{-2}}$. Our analysis reveals increased cold neutral medium volume-filling factors (VFF) outside stellar clusters, reduced thermally unstable gas, and sharper warm–cold gas separation. The variable FUV field also promotes a cold diffuse gas phase with a molecular component, exhibiting a VFF of $\sim 5{-}10$ per cent.

Item Type:	Article
Creators:	Creators Email ORCID ORCID Put Code Rathjen, Tim-Eric UNSPECIFIED https://orcid.org/0000-0002-8228-3715 UNSPECIFIED Walch, Stefanie UNSPECIFIED https://orcid.org/0000-0001-6941-7638 UNSPECIFIED Naab, Thorsten UNSPECIFIED https://orcid.org/0000-0002-7314-2558 UNSPECIFIED Nürnberger, Pierre UNSPECIFIED https://orcid.org/0000-0003-4384-3115 UNSPECIFIED Wünsch, Richard UNSPECIFIED https://orcid.org/0000-0003-1848-8967 UNSPECIFIED Seifried, Daniel UNSPECIFIED https://orcid.org/0000-0002-0368-9160 UNSPECIFIED Glover, Simon C O UNSPECIFIED https://orcid.org/0000-0001-6708-1317 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-811245
Identification Number:	10.1093/mnras/staf792
Journal or Publication Title:	Monthly Notices of the Royal Astronomical Society
Volume:	540
Number:	2
Page Range:	pp. 1462-1490
Number of Pages:	29
Date:	30 May 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 MHD ; radiative transfer ; methods: numerical ; stars: formation ; SM: abundances ; galaxies: ISM English
['eprint_fieldname_oa_funders' not defined]:	Publikationsfonds UzK
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/81124