The EDGE-CALIFA survey: the resolved star formation efficiency and local physical conditions

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The EDGE-CALIFA Survey: The Resolved Star Formation Efficiency and Local Physical Conditions V. Villanueva1, A. Bolatto1,2, S. Vogel1, R. C. Levy1, S. F. Sánchez3, J. Barrera-Ballesteros3, T. Wong4, E. Rosolowsky5, D. Colombo6, M. Rubio7Show full author list

Published 2021 December 10 • © 2021. The American Astronomical Society. All rights reserved. The Astrophysical Journal, Volume 923, Number 1 Citation V. Villanueva et al 2021 ApJ 923 60 DownloadArticle PDF DownloadArticle ePub Figures Tables References Article data 153 Total downloads 11 citation on Dimensions. Turn on MathJax Get permission to re-use this article

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Share this content via email Share on Facebook (opens new window) Share on Twitter (opens new window) Share on Mendeley (opens new window) Article information Abstract We measure the star formation rate (SFR) per unit gas mass and the star formation efficiency (SFEgas for total gas, SFEmol for the molecular gas) in 81 nearby galaxies selected from the EDGE-CALIFA survey, using 12CO (J = 1–0) and optical IFU data. For this analysis we stack CO spectra coherently by using the velocities of Hα detections to detect fainter CO emission out to galactocentric radii rgal ∼ 1.2r25 (∼3Re) and include the effects of metallicity and high surface densities in the CO-to-H2 conversion. We determine the scale lengths for the molecular and stellar components, finding a close to 1:1 relation between them. This result indicates that CO emission and star formation activity are closely related. We examine the radial dependence of SFEgas on physical parameters such as galactocentric radius, stellar surface density Σ⋆, dynamical equilibrium pressure PDE, orbital timescale τorb, and the Toomre Q stability parameter (including star and gas Qstar+gas). We observe a generally smooth, continuous exponential decline in the SFEgas with rgal. The SFEgas dependence on most of the physical quantities appears to be well described by a power law. Our results also show a flattening in the SFEgas–τorb relation at $\mathrm{log}[{\tau }_{\mathrm{orb}}]\sim 7.9\mbox{--}8.1$ and a morphological dependence of the SFEgas per orbital time, which may reflect star formation quenching due to the presence of a bulge component. We do not find a clear correlation between SFEgas and Qstar+gas.