From giant clumps to clouds - III. The connection between star formation and turbulence in the ISM
Artikel i vetenskaplig tidskrift, 2022

Supersonic gas turbulence is a ubiquitous property of the interstellar medium. The level of turbulence, quantified by the gas velocity dispersion (sigma(g)), is observed to increase with the star formation rate (SFR) of a galaxy, but it is yet not established whether this trend is driven by stellar feedback or gravitational instabilities. In this work, we carry out hydrodynamical simulations of entire disc galaxies, with different gas fractions, to understand the origins of the SFR-sigma(g) relation. We show that disc galaxies reach the same levels of turbulence regardless of the presence of stellar feedback processes, and argue that this is an outcome of the way disc galaxies regulate their gravitational stability. The simulations match the SFR-sigma(g) relation up to SFRs of the order of tens of M-circle dot yr(-1) and sigma(g) similar to 50 km s(-1) in neutral hydrogen and molecular gas, but fail to reach the very large values (> 100 km s(-1)) reported in the literature for rapidly star-forming galaxies. We demonstrate that such high values of sigma(g) can be explained by ( 1) insufficient beam smearing corrections in observations and (2) stellar feedback being coupled to the ionized gas phase traced by recombination lines. Given that the observed SFR-sigma(g) relation is composed of highly heterogeneous data, with sigma(g) at high SFRs almost exclusively being derived from H alpha observations of high-redshift galaxies with complex morphologies, we caution against analytical models that attempt to explain the SFR-sigma(g) relation without accounting for these effects.

ISM: evolution

ISM: kinematics and dynamics

methods: numerical

galaxies: star formation

turbulence

Författare

Timmy Ejdetjarn

Stockholms universitet

Lunds universitet

Oscar Agertz

Lunds universitet

Goran Ostlin

Stockholms universitet

Florent Renaud

Lunds universitet

Alessandro Romeo

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 514 1 480-496

Ämneskategorier

Astronomi, astrofysik och kosmologi

Annan kemi

Strömningsmekanik och akustik

DOI

10.1093/mnras/stac1414

Mer information

Senast uppdaterat

2022-06-28