The Astronomical Journal (Jan 2023)
A Two-Component Probability Distribution Function Describes the Mid-IR Emission from the Disks of Star-forming Galaxies
- Debosmita Pathak,
- Adam K. Leroy,
- Todd A. Thompson,
- Laura A. Lopez,
- Francesco Belfiore,
- Médéric Boquien,
- Daniel A. Dale,
- Simon C. O. Glover,
- Ralf S. Klessen,
- Eric W. Koch,
- Erik Rosolowsky,
- Karin M. Sandstrom,
- Eva Schinnerer,
- Rowan Smith,
- Jiayi Sun,
- Jessica Sutter,
- Thomas G. Williams,
- Frank Bigiel,
- Yixian Cao,
- Jérémy Chastenet,
- Mélanie Chevance,
- Ryan Chown,
- Eric Emsellem,
- Christopher M. Faesi,
- Kirsten L. Larson,
- Janice C. Lee,
- Sharon Meidt,
- Eve C. Ostriker,
- Lise Ramambason,
- Sumit K. Sarbadhicary,
- David A. Thilker
Affiliations
- Debosmita Pathak
- ORCiD
- Department of Astronomy, Ohio State University , 180 W. 18th Avenue, Columbus, OH 43210, USA ; [email protected]
- Adam K. Leroy
- ORCiD
- Department of Astronomy, Ohio State University , 180 W. 18th Avenue, Columbus, OH 43210, USA ; [email protected]; Center for Cosmology and Astroparticle Physics , 191 West Woodruff Avenue, Columbus, OH 43210, USA
- Todd A. Thompson
- ORCiD
- Department of Astronomy, Ohio State University , 180 W. 18th Avenue, Columbus, OH 43210, USA ; [email protected]; Center for Cosmology and Astroparticle Physics , 191 West Woodruff Avenue, Columbus, OH 43210, USA; Department of Physics, Ohio State University , 91 West Woodruff Avenue, Columbus, OH 43210, USA
- Laura A. Lopez
- ORCiD
- Department of Astronomy, Ohio State University , 180 W. 18th Avenue, Columbus, OH 43210, USA ; [email protected]; Center for Cosmology and Astroparticle Physics , 191 West Woodruff Avenue, Columbus, OH 43210, USA; Flatiron Institute, Center for Computational Astrophysics , New York, NY 10010, USA
- Francesco Belfiore
- ORCiD
- INAF—Osservatorio Astrofisico di Arcetri , Largo E. Fermi 5, I-50157, Firenze, Italy
- Médéric Boquien
- ORCiD
- Instituto de Alta Investigación, Universidad de Tarapacá , Casilla 7D, Arica, Chile
- Daniel A. Dale
- ORCiD
- Department of Physics and Astronomy, University of Wyoming , Laramie, WY 82071, USA
- Simon C. O. Glover
- ORCiD
- Universität Heidelberg , Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Straße 2, D-69120 Heidelberg, Germany
- Ralf S. Klessen
- ORCiD
- Universität Heidelberg , Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Straße 2, D-69120 Heidelberg, Germany; Universität Heidelberg , Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Im Neuenheimer Feld 205, D-69120 Heidelberg, Germany
- Eric W. Koch
- ORCiD
- Center for Astrophysics ∣Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Erik Rosolowsky
- ORCiD
- Department of Physics, University of Alberta , Edmonton, AB T6G 2E1, Canada
- Karin M. Sandstrom
- ORCiD
- Department of Astronomy & Astrophysics, University of California , San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
- Eva Schinnerer
- ORCiD
- Max Planck Institute for Astronomy , Königstuhl 17, D-69117, Germany
- Rowan Smith
- ORCiD
- Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, UK
- Jiayi Sun
- ORCiD
- Department of Physics and Astronomy, McMaster University , 1280 Main Street West, Hamilton, ON L8S 4M1, Canada; Canadian Institute for Theoretical Astrophysics (CITA), University of Toronto , 60 St George Street, Toronto, ON M5S 3H8, Canada
- Jessica Sutter
- ORCiD
- Department of Astronomy & Astrophysics, University of California , San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
- Thomas G. Williams
- ORCiD
- Sub-department of Astrophysics, Department of Physics, University of Oxford , Keble Road, Oxford OX1 3RH, UK
- Frank Bigiel
- ORCiD
- Argelander-Institut für Astronomie, Universität Bonn , Auf dem Hügel 71, D-53121 Bonn, Germany
- Yixian Cao
- ORCiD
- Max-Planck-Institut für Extraterrestrische Physik (MPE) , Giessenbachstr. 1, D-85748 Garching, Germany
- Jérémy Chastenet
- ORCiD
- Sterrenkundig Observatorium, Ghent University , Krijgslaan 281-S9, B-9000 Gent, Belgium
- Mélanie Chevance
- ORCiD
- Universität Heidelberg , Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Straße 2, D-69120 Heidelberg, Germany
- Ryan Chown
- ORCiD
- Department of Physics & Astronomy, University of Western Ontario , London, ON N6A 3K7, Canada
- Eric Emsellem
- ORCiD
- European Southern Observatory , Karl-Schwarzschild-Straß 2, D-85748, Garching, Germany; Univ Lyon, Univ Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon UMR5574 , F-69230, Saint-Genis-Laval, France
- Christopher M. Faesi
- ORCiD
- Department of Physics, University of Connecticut , Storrs, CT 06269, USA
- Kirsten L. Larson
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Janice C. Lee
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Sharon Meidt
- ORCiD
- Sterrenkundig Observatorium, Universiteit Gent , Krijgslaan 281 S9, B-9000 Gent, Belgium
- Eve C. Ostriker
- ORCiD
- Department of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USA
- Lise Ramambason
- ORCiD
- Universität Heidelberg , Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Straße 2, D-69120 Heidelberg, Germany
- Sumit K. Sarbadhicary
- ORCiD
- Department of Astronomy, Ohio State University , 180 W. 18th Avenue, Columbus, OH 43210, USA ; [email protected]
- David A. Thilker
- ORCiD
- Department of Physics and Astronomy, The Johns Hopkins University , Baltimore, MD 21218, USA
- DOI
- https://doi.org/10.3847/1538-3881/ad110d
- Journal volume & issue
-
Vol. 167,
no. 1
p. 39
Abstract
High-resolution JWST-MIRI images of nearby spiral galaxies reveal emission with complex substructures that trace dust heated both by massive young stars and the diffuse interstellar radiation field. We present high angular (0.″85) and physical resolution (20–80 pc) measurements of the probability distribution function (PDF) of mid-infrared (mid-IR) emission (7.7–21 μ m) from 19 nearby star-forming galaxies from the PHANGS-JWST Cycle 1 Treasury. The PDFs of mid-IR emission from the disks of all 19 galaxies consistently show two distinct components: an approximately lognormal distribution at lower intensities and a high-intensity power law component. These two components only emerge once individual star-forming regions are resolved. Comparing with locations of H ii regions identified from Very Large Telescope/MUSE H α mapping, we infer that the power-law component arises from star-forming regions and thus primarily traces dust heated by young stars. In the continuum-dominated 21 μ m band, the power law is more prominent and contains roughly half of the total flux. At 7.7–11.3 μ m, the power law is suppressed by the destruction of small grains (including PAHs) close to H ii regions, while the lognormal component tracing the dust column in diffuse regions appears more prominent. The width and shape of the lognormal diffuse emission PDFs in galactic disks remain consistent across our sample, implying a lognormal gas column density N (H) ≈ 10 ^21 cm ^−2 shaped by supersonic turbulence with typical (isothermal) turbulent Mach numbers ≈5−15. Finally, we describe how the PDFs of galactic disks are assembled from dusty H ii regions and diffuse gas and discuss how the measured PDF parameters correlate with global properties such as star formation rate and gas surface density.
Keywords
- Interstellar medium
- Extragalactic astronomy
- Dust physics
- H II regions
- Infrared astronomy
- Stellar feedback
