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PHANGS–JWST First Results: Dust-embedded Star Clusters in NGC 7496 Selected via 3.3 μm PAH Emission


Abstract The earliest stages of star formation occur enshrouded in dust and are not observable in the optical. Here we leverage the extraordinary new high-resolution infrared imaging from JWST to begin the study of dust-embedded star clusters in nearby galaxies throughout the Local Volume. We present a technique for identifying dust-embedded clusters in NGC 7496 (18.7 Mpc), the first galaxy to be observed by the PHANGS–JWST Cycle 1 Treasury Survey. We select sources that have strong 3.3 μ m PAH emission based on a F300M − F335M color excess and identify 67 candidate embedded clusters. Only eight of these are found in the PHANGS-HST optically selected cluster catalog, and all are young (six have SED fit ages of ∼1 Myr). We find that this sample of embedded cluster candidates may significantly increase the census of young clusters in NGC 7496 from the PHANGS-HST catalog; the number of clusters younger than ∼2 Myr could be increased by a factor of 2. Candidates are preferentially located in dust lanes and are coincident with the peaks in the PHANGS-ALMA CO (2–1) maps. We take a first look at concentration indices, luminosity functions, SEDs spanning from 2700 Å to 21 μ m, and stellar masses (estimated to be between ∼10 4 and 10 5 M ⊙ ). The methods tested here provide a basis for future work to derive accurate constraints on the physical properties of embedded clusters, characterize the completeness of cluster samples, and expand analysis to all 19 galaxies in the PHANGS–JWST sample, which will enable basic unsolved problems in star formation and cluster evolution to be addressed.
Authors M.M. Rodríguez ORCID , Janice Lee ORCID , Bradley C. Whitmore ORCID , David A. Thilker ORCID , Daniel Maschmann ORCID , Rupali Chandar ORCID , Sinan Deger ORCID , M. Boquien ORCID , Daniel A. Dale University of WyomingORCID , Kirsten L. Larson ORCID , Thomas G. Williams ORCID , Hwi Kim ORCID , E. Schinnerer ORCID , Erik Rosolowsky ORCID , Adam K. Leroy ORCID , Éric Emsellem ORCID , Karin Sandström ORCID , J. M. Diederik Kruijssen ORCID , Kathryn Grasha ORCID , Elizabeth J. Watkins ORCID , Ashley T. Barnes ORCID , Mattia C. Sormani ORCID , Jaeyeon Kim ORCID , Gagandeep S. Anand ORCID , Mélanie Chevance ORCID , Frank Bigiel ORCID , Ralf S. Klessen ORCID , Hamid Hassani ORCID , Daizhong Liu ORCID , Christopher M. Faesi ORCID , Yixian Cao ORCID , Francesco Belfiore ORCID , Ismael Pessa ORCID , Kathryn Kreckel ORCID , Brent Groves ORCID , J. Pety ORCID , R. Indebetouw ORCID , Oleg V. Egorov ORCID , Guillermo A. Blanc ORCID , Toshiki Saito ORCID , Annie Hughes ORCID
Journal Info IOP Publishing | The Astrophysical Journal Letters , vol: 944 , iss: 2 , pages: L26 - L26
Publication Date 2/1/2023
ISSN 2041-8205
TypeKeyword Image article
Open Access gold Gold Access
DOI https://doi.org/10.3847/2041-8213/aca653
KeywordsKeyword Image Young Stellar Objects (Score: 0.493704)