The Astrophysical Journal (Jan 2024)
PHANGS-ML: Dissecting Multiphase Gas and Dust in Nearby Galaxies Using Machine Learning
- Dalya Baron,
- Karin M. Sandstrom,
- Erik Rosolowsky,
- Oleg V. Egorov,
- Ralf S. Klessen,
- Adam K. Leroy,
- Médéric Boquien,
- Eva Schinnerer,
- Francesco Belfiore,
- Brent Groves,
- Jérémy Chastenet,
- Daniel A. Dale,
- Guillermo A. Blanc,
- José E. Méndez-Delgado,
- Eric W. Koch,
- Kathryn Grasha,
- Mélanie Chevance,
- David A. Thilker,
- Dario Colombo,
- Thomas G. Williams,
- Debosmita Pathak,
- Jessica Sutter,
- Toby Brown,
- John F. Wu,
- Josh E. G. Peek,
- Eric Emsellem,
- Kirsten L. Larson,
- Justus Neumann
Affiliations
- Dalya Baron
- ORCiD
- The Observatories of the Carnegie Institution for Science , 813 Santa Barbara Street, Pasadena, CA 91101, USA ; [email protected]
- Karin M. Sandstrom
- ORCiD
- Department of Astronomy & Astrophysics, University of California , San Diego. 9500 Gilman Drive, La Jolla, CA 92093, USA
- Erik Rosolowsky
- ORCiD
- Department of Physics, University of Alberta , Edmonton, Alberta, T6G 2E1, Canada
- Oleg V. Egorov
- ORCiD
- Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg , Mönchhofstraße 12-14, 69120 Heidelberg, Germany
- Ralf S. Klessen
- ORCiD
- Universität Heidelberg , Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Straße 2,69120 Heidelberg, Germany; Universität Heidelberg , Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
- Adam K. Leroy
- ORCiD
- Department of Astronomy, Ohio State University , 180 W. 18th Avenue, Columbus, OH 43210, USA; Center for Cosmology and Astroparticle Physics , 191 West Woodruff Avenue, Columbus, OH 43210, USA
- Médéric Boquien
- ORCiD
- Université Côte d’Azur , Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, 06000, Nice, France
- Eva Schinnerer
- ORCiD
- Max Planck Institute for Astronomy , Königstuhl 17, D-69117, Germany
- Francesco Belfiore
- ORCiD
- INAF —Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50157, Firenze, Italy
- Brent Groves
- ORCiD
- International Centre for Radio Astronomy Research, University of Western Australia , 35 Stirling Highway, Crawley, WA 6009, Australia
- Jérémy Chastenet
- ORCiD
- Sterrenkundig Observatorium, Ghent University , Krijgslaan 281-S9, 9000 Gent, Belgium
- Daniel A. Dale
- ORCiD
- Department of Physics and Astronomy, University of Wyoming , Laramie, WY 82071, USA
- Guillermo A. Blanc
- ORCiD
- The Observatories of the Carnegie Institution for Science , 813 Santa Barbara Street, Pasadena, CA 91101, USA ; [email protected]; Departamento de Astronomía, Universidad de Chile , Camino del Observatorio 1515, Las Condes, Santiago, Chile
- José E. Méndez-Delgado
- ORCiD
- Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg , Mönchhofstraße 12-14, 69120 Heidelberg, Germany
- Eric W. Koch
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, 02138 Cambridge, MA, USA
- Kathryn Grasha
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia; ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) , Australia
- Mélanie Chevance
- ORCiD
- Zentrum für Astronomie der Universität Heidelberg , Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany; Cosmic Origins Of Life (COOL) Research DAO , Germany
- David A. Thilker
- ORCiD
- Center for Astrophysical Sciences, Johns Hopkins University , 3400 N. Charles Street, Baltimore, MD 21218, USA
- Dario Colombo
- ORCiD
- Argelander-Institut für Astronomie, Universität Bonn , Auf dem Hügel 71, 53121 Bonn, Germany; Max-Planck-Institut für Radioastronomie , Auf dem Hügel 69, 53121 Bonn, Germany
- Thomas G. Williams
- ORCiD
- Sub-department of Astrophysics, Department of Physics, University of Oxford , Keble Road, Oxford OX1 3RH, UK
- Debosmita Pathak
- ORCiD
- Department of Astronomy, Ohio State University , 180 W. 18th Avenue, Columbus, OH 43210, USA
- Jessica Sutter
- ORCiD
- Department of Astronomy & Astrophysics, University of California , San Diego. 9500 Gilman Drive, La Jolla, CA 92093, USA
- Toby Brown
- ORCiD
- Herzberg Astronomy and Astrophysics Research Centre , National Research Council of Canada, 5071 West Saanich Road, Victoria, BC, V9E 2E7, Canada
- John F. Wu
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Physics & Astronomy, Johns Hopkins University , 3400 N. Charles Street, Baltimore, MD 21218, USA
- Josh E. G. Peek
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Physics & Astronomy, Johns Hopkins University , 3400 N. Charles Street, Baltimore, MD 21218, USA
- Eric Emsellem
- ORCiD
- European Southern Observatory , Karl-Schwarzschild-Straße 2, 85748, Garching, Germany; University Lyon , Univ Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon UMR5574, 69230, Saint-Genis-Laval, France
- Kirsten L. Larson
- ORCiD
- AURA for the European Space Agency (ESA), Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Justus Neumann
- ORCiD
- Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg, Germany
- DOI
- https://doi.org/10.3847/1538-4357/ad39e5
- Journal volume & issue
-
Vol. 968,
no. 1
p. 24
Abstract
The PHANGS survey uses Atacama Large Millimeter/submillimeter Array, Hubble Space Telescope, Very Large Telescope, and JWST to obtain an unprecedented high-resolution view of nearby galaxies, covering millions of spatially independent regions. The high dimensionality of such a diverse multiwavelength data set makes it challenging to identify new trends, particularly when they connect observables from different wavelengths. Here, we use unsupervised machine-learning algorithms to mine this information-rich data set to identify novel patterns. We focus on three of the PHANGS-JWST galaxies, for which we extract properties pertaining to their stellar populations; warm ionized and cold molecular gas; and polycyclic aromatic hydrocarbons (PAHs), as measured over 150 pc scale regions. We show that we can divide the regions into groups with distinct multiphase gas and PAH properties. In the process, we identify previously unknown galaxy-wide correlations between PAH band and optical line ratios and use our identified groups to interpret them. The correlations we measure can be naturally explained in a scenario where the PAHs and the ionized gas are exposed to different parts of the same radiation field that varies spatially across the galaxies. This scenario has several implications for nearby galaxies: (i) The uniform PAH ionized fraction on 150 pc scales suggests significant self-regulation in the interstellar medium, (ii) the PAH 11.3/7.7 μ m band ratio may be used to constrain the shape of the non-ionizing far-ultraviolet to optical part of the radiation field, and (iii) the varying radiation field affects line ratios that are commonly used as PAH size diagnostics. Neglecting this effect leads to incorrect or biased PAH sizes.
Keywords
- Astrostatistics techniques
- Astronomy data visualization
- Warm ionized medium
- Interstellar dust
- Polycyclic aromatic hydrocarbons
