The ALMaQUEST survey – III. Scatter in the resolved star-forming main sequence is primarily due to variations in star formation efficiency

Ellison, Sara L, Thorp, Mallory D, Lin, Lihwai, Pan, Hsi-An, Bluck, Asa F L, Scudder, Jillian M, Teimoorinia, Hossen, Sanchez, Sebastian F and Sargent, Mark (2020) The ALMaQUEST survey – III. Scatter in the resolved star-forming main sequence is primarily due to variations in star formation efficiency. Monthly Notices of the Royal Astronomical Society, 493 (1). L39-L43. ISSN 0035-8711

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Abstract

Using a sample of 11,478 spaxels in 34 galaxies with molecular gas, star formation and stellar maps taken from the ALMA-MaNGA QUEnching and STar formation (ALMaQUEST) survey, we investigate the parameters that correlate with variations in star formation rates on kpc scales. We use a combination of correlation statistics and an artificial neural network to quantify the parameters that drive both the absolute star formation rate surface density (Sigma_SFR), as well as its scatter around the resolved star forming main sequence (Delta Sigma_SFR). We find that Sigma_SFR is primarily regulated by molecular gas surface density (Sigma_H2) with a secondary dependence on stellar mass surface density (Sigma_*), as expected from an `extended Kennicutt-Schmidt relation'. However, Delta Sigma_SFR is driven primarily by changes in star formation efficiency (SFE), with variations in gas fraction playing a secondary role. Taken together, our results demonstrate that whilst the absolute rate of star formation is primarily set by the amount of molecular gas, the variation of star formation rate above and below the resolved star forming main sequence (on kpc scales) is primarily due to changes in SFE.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Astronomy Centre
Subjects: Q Science > QB Astronomy
Depositing User: Mark Sargent
Date Deposited: 06 Jan 2020 14:01
Last Modified: 04 Mar 2020 11:30
URI: http://sro.sussex.ac.uk/id/eprint/89167

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