Journal Article

The effect of ISM turbulence on the gravitational instability of galactic discs

Volker Hoffmann and Alessandro B. Romeo

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 425, issue 2, pages 1511-1520
Published in print September 2012 | ISSN: 0035-8711
Published online September 2012 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2012.21675.x
The effect of ISM turbulence on the gravitational instability of galactic discs

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Abstract

We investigate the gravitational instability of galactic discs, treating stars and cold interstellar gas as two distinct components, and taking into account the phenomenology of turbulence in the interstellar medium (ISM), i.e. the Larson-type scaling relations observed in the molecular and atomic gas. Besides deriving general properties of such systems, we analyse a large sample of galaxies from The H i Nearby Galaxy Survey (THINGS), and show in detail how interstellar turbulence affects disc instability in star-forming spirals. We find that turbulence has a significant effect on both the inner and the outer regions of the disc. In particular, it drives the inner gas disc to a regime of transition between two instability phases and makes the outer disc more prone to star-dominated instabilities.

Keywords: instabilities; turbulence; ISM: kinematics and dynamics; ISM: structure; galaxies: ISM; galaxies: kinematics and dynamics

Journal Article.  7786 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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