The WISDOM of power spectra: how the galactic gravitational potential impacts a galaxy?s central gas reservoir in simulations and observations

Gensior, Jindra, Davis, Timothy A. ORCID: https://orcid.org/0000-0003-4932-9379, Bureau, Martin, Kruijssen, J. M. Diederik, Cappellari, Michele, Ruffa, Ilaria and Williams, Thomas G. 2023. The WISDOM of power spectra: how the galactic gravitational potential impacts a galaxy?s central gas reservoir in simulations and observations. Monthly Notices of the Royal Astronomical Society 526 (4) , pp. 5590-5611. 10.1093/mnras/stad3127

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Abstract

Observations indicate that the central gas discs are smoother in early-type galaxies than their late-type counterparts, while recent simulations predict that the dynamical suppression of star formation in spheroid-dominated galaxies is preceded by the suppression of fragmentation of their interstellar media. The mass surface density power spectrum is a powerful tool to constrain the degree of structure within a gas reservoir. Specifically here, we focus on the power spectrum slope and aim to constrain whether the shear induced by a dominant spheroidal potential can induce sufficient turbulence to suppress fragmentation, resulting in the smooth central gas discs observed. We compute surface density power spectra for the nuclear gas reservoirs of fourteen simulated isolated galaxies and twelve galaxies observed as part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM) project. Both simulated and observed galaxies range from disc-dominated galaxies to spheroids, with central stellar mass surface densities, a measure of bulge dominance, varying by more than an order of magnitude. For the simulations, the power spectra steepen with increasing central stellar mass surface density, thereby clearly linking the suppression of fragmentation to the shear-driven turbulence induced by the spheroid. The WISDOM observations show a different (but potentially consistent) picture: while there is no correlation between the power spectrum slopes and the central stellar mass surface densities, the slopes scatter around a value of 2.6. This is similar to the behaviour of the slopes of the simulated galaxies with high central stellar mass surface densities, and could indicate that high shear eventually drives incompressible turbulence.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Publisher:	Oxford University Press
ISSN:	0035-8711
Date of First Compliant Deposit:	19 December 2023
Date of Acceptance:	9 October 2023
Last Modified:	21 Dec 2023 15:45
URI:	https://orca.cardiff.ac.uk/id/eprint/164977

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