1. Stellar structures, molecular gas, and star formation across the PHANGS sample of nearby galaxies
- Author
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M. Querejeta, E. Schinnerer, S. Meidt, J. Sun, A. K. Leroy, E. Emsellem, R. S. Klessen, J. C. Muñoz-Mateos, H. Salo, E. Laurikainen, I. Bešlić, G. A. Blanc, M. Chevance, D. A. Dale, C. Eibensteiner, C. Faesi, A. García-Rodríguez, S. C. O. Glover, K. Grasha, J. Henshaw, C. Herrera, A. Hughes, K. Kreckel, J. M. D. Kruijssen, D. Liu, E. J. Murphy, H.-A. Pan, J. Pety, A. Razza, E. Rosolowsky, T. Saito, A. Schruba, A. Usero, E. J. Watkins, T. G. Williams, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
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EDGE-CALIFA SURVEY ,DEPLETION TIME ,FORMATION EFFICIENCY ,SPIRAL ARMS ,FOS: Physical sciences ,MORPHOLOGICAL CLASSIFICATIONS ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,33 GHZ OBSERVATIONS ,Astrophysics::Solar and Stellar Astrophysics ,FORMATION LAW ,Astrophysics::Galaxy Astrophysics ,Physics ,ISM [galaxies] ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,Star formation ,100 PC SCALES ,SPITZER SURVEY ,Astronomy and Astrophysics ,Sample (graphics) ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Physics and Astronomy ,Space and Planetary Science ,[SDU]Sciences of the Universe [physics] ,Astrophysics of Galaxies (astro-ph.GA) ,galaxies: star formation ,structure [galaxies] ,galaxies: structure ,Astrophysics::Earth and Planetary Astrophysics ,star formation [galaxies] ,BARRED GALAXIES ,galaxies: ISM - Abstract
We identify stellar structures in the PHANGS sample of 74 nearby galaxies and construct morphological masks of sub-galactic environments based on Spitzer 3.6 micron images. At the simplest level, we distinguish centres, bars, spiral arms, interarm and discs without strong spirals. Slightly more sophisticated masks include rings and lenses, publicly released but not explicitly used in this paper. We examine trends using PHANGS-ALMA CO(2-1) intensity maps and tracers of star formation. The interarm regions and discs without strong spirals dominate in area, whereas molecular gas and star formation are quite evenly distributed among the five basic environments. We reproduce the molecular Kennicutt-Schmidt relation with a slope compatible with unity within the uncertainties, without significant slope differences among environments. In contrast to early studies, we find that bars are not always deserts devoid of gas and star formation, but instead they show large diversity. Similarly, spiral arms do not account for most of the gas and star formation in disc galaxies, and they do not have shorter depletion times than the interarm regions. Spiral arms accumulate gas and star formation, without systematically boosting the star formation efficiency. Centres harbour remarkably high surface densities and on average shorter depletion times than other environments. Centres of barred galaxies show higher surface densities and wider distributions compared to the outer disc; yet, depletion times are similar to unbarred galaxies, suggesting highly intermittent periods of star formation when bars episodically drive gas inflow, without enhancing the central star formation efficiency permanently. In conclusion, we provide quantitative evidence that stellar structures in galaxies strongly affect the organisation of molecular gas and star formation, but their impact on star formation efficiency is more subtle., 28 pages, 11 figures, accepted for publication in A&A