The Astrophysical Journal (Jan 2025)
Tracing the Earliest Stages of Star and Cluster Formation in 19 Nearby Galaxies with PHANGS-JWST and HST: Compact 3.3 μm Polycyclic Aromatic Hydrocarbon Emitters and Their Relation to the Optical Census of Star Clusters
- M. Jimena Rodríguez,
- Janice C. Lee,
- Remy Indebetouw,
- B. C. Whitmore,
- Daniel Maschmann,
- Thomas G. Williams,
- Rupali Chandar,
- A. T. Barnes,
- Oleg Y. Gnedin,
- Karin M. Sandstrom,
- Erik Rosolowsky,
- Adam K. Leroy,
- David A. Thilker,
- Hwihyun Kim,
- Jiayi Sun,
- Ralf S. Klessen,
- Brent Groves,
- Aida Wofford,
- Médéric Boquien,
- Daniel A. Dale,
- Leonardo Úbeda,
- Kirsten L. Larson,
- Kathryn Grasha,
- Kelsey E. Johnson,
- Rebecca C. Levy,
- Frank Bigiel,
- Hamid Hassani,
- Sumit K. Sarbadhicary
Affiliations
- M. Jimena Rodríguez
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]; Steward Observatory , University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA; Instituto de Astrofísica de La Plata , CONICET–UNLP, Paseo del Bosque S/N, B1900FWA La Plata, Argentina
- Janice C. Lee
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]; Steward Observatory , University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
- Remy Indebetouw
- ORCiD
- University of Virginia Astronomy Department , P.O. Box 400325, Charlottesville, VA 22904, USA; National Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903, USA
- B. C. Whitmore
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]
- Daniel Maschmann
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]; Steward Observatory , University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
- Thomas G. Williams
- ORCiD
- Sub-department of Astrophysics , Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH, UK; Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117 Heidelberg, Germany
- Rupali Chandar
- ORCiD
- Ritter Astrophysical Research Center , University of Toledo, Toledo, OH 43606, USA
- A. T. Barnes
- ORCiD
- European Southern Observatory (ESO) , Karl-Schwarzschild-Straße 2, 85748 Garching, Germany
- Oleg Y. Gnedin
- ORCiD
- Department of Astronomy, University of Michigan , Ann Arbor, MI 48109, USA
- 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, AB T6G 2E1, Canada
- Adam K. Leroy
- ORCiD
- Department of Astronomy, The Ohio State University , Columbus, OH 43210, USA
- David A. Thilker
- ORCiD
- Department of Physics and Astronomy, The Johns Hopkins University , Baltimore, MD 21218, USA
- Hwihyun Kim
- ORCiD
- Gemini Observatory/NSF’s NOIRLab , 950 North Cherry Avenue, Tucson, AZ, USA
- Jiayi Sun
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USA
- 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
- Brent Groves
- ORCiD
- International Centre for Radio Astronomy Research , University of Western Australia, 7 Fairway, Crawley, 6009 WA, Australia
- Aida Wofford
- ORCiD
- Department of Astronomy & Astrophysics, University of California , San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Instituto de Astronomía , Universidad Nacional Autónoma de México, Unidad Académica en Ensenada, Km 103 Carr. Tijuana-Ensenada, Ensenada 22860, Mexico
- Médéric Boquien
- ORCiD
- Université Côte d’Azur , Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, 06000, Nice, France
- Daniel A. Dale
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]; Department of Physics and Astronomy, University of Wyoming , Laramie, WY 82071, USA
- Leonardo Úbeda
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA ; [email protected]
- Kirsten L. Larson
- ORCiD
- AURA for the European Space Agency (ESA) , Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, 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
- Kelsey E. Johnson
- ORCiD
- Department of Astronomy, University of Virginia , Charlottesville, VA 22904, USA
- Rebecca C. Levy
- ORCiD
- Steward Observatory , University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
- Frank Bigiel
- ORCiD
- Argelander-Institut für Astronomie , Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
- Hamid Hassani
- ORCiD
- Department of Physics, University of Alberta , Edmonton, AB T6G 2E1, Canada
- Sumit K. Sarbadhicary
- ORCiD
- Department of Astronomy, The Ohio State University , Columbus, OH 43210, USA; Department of Physics, The Ohio State University , Columbus, OH 43210, USA; Center for Cosmology & Astro-Particle Physics , The Ohio State University, Columbus, OH 43210, USA
- DOI
- https://doi.org/10.3847/1538-4357/adbb69
- Journal volume & issue
-
Vol. 983,
no. 2
p. 137
Abstract
The earliest stages of star and cluster formation are hidden within dense cocoons of gas and dust, limiting their detection at optical wavelengths. With the unprecedented infrared capabilities of JWST, we can now observe dust-enshrouded star formation with ∼10 pc resolution out to ∼20 Mpc. Early findings from PHANGS-JWST suggest that 3.3 μ m polycyclic aromatic hydrocarbon (PAH) emission can identify star clusters in their dust-embedded phases. Here, we extend this analysis to 19 galaxies from the PHANGS-JWST Cycle 1 Treasury survey, providing the first characterization of compact sources exhibiting 3.3 μ m PAH emission across a diverse sample of nearby star-forming galaxies. We establish a selection criteria based on a median color threshold of F300M − F335M = 0.67 at F335M = 20 and identify 1816 sources. These sources are predominantly located in dust lanes, spiral arms, rings, and galaxy centers, with ∼87% showing concentration indices (CIs) similar to optically detected star clusters. Comparison with the PHANGS-HST catalogs suggests that PAH emission fades within ∼3 Myr. The H α equivalent width of PAH emitters is 1–2.8 times higher than that of young PHANGS-HST clusters, providing evidence that PAH emitters are on average younger. Analysis of the bright portions of luminosity functions (which should not suffer from incompleteness) shows that young dusty clusters may increase the number of optically visible ≤3 Myr old clusters in PHANGS-HST by a factor between ∼1.8× and 8.5×.
Keywords
- Star formation
- Young star clusters
- Polycyclic aromatic hydrocarbons
- Star clusters
- Spiral galaxies
- James Webb Space Telescope
