_version_ 1866908654685388800
author Graham, Gabrielle B.
Dale, Daniel A.
Smith, Chase L.
Brann, Elisabeth
Conder, Kaycee D.
Crowe, Samuel
Dhileepkumar, Sumitra
Imming, Nicole A.
Mendez, Emilio
Pleska, Zachary
Sako, Kelsey
Amiri, Amirnezam
Barnes, Ashley T.
Boquien, Médéric
Chandar, Rupali
Chown, Ryan
Gnedin, Oleg Y.
Grasha, Kathryn
Hannon, Stephen
Hassani, Hamid
Indebetouw, Rémy
Kim, Hwihyun
Kim, Jaeyeon
Koziol, Hannah
Larson, Kirsten L.
Lee, Janice C.
Leroy, Adam K.
Oakes, Elias K.
Rodríguez, M. Jimena
Rosolowsky, Erik
Sandstrom, Karin
Schinnerer, Eva
Sutter, Jessica
Thilker, David A.
Ubeda, Leonardo
Whitmore, Bradley C.
Weinbeck, Tony D.
Williams, Thomas G.
Wofford, Aida
Méndez-Delgado, J. Eduardo
Tian, Qiushi Chris
Collaboration, the PHANGS
author_facet Graham, Gabrielle B.
Dale, Daniel A.
Smith, Chase L.
Brann, Elisabeth
Conder, Kaycee D.
Crowe, Samuel
Dhileepkumar, Sumitra
Imming, Nicole A.
Mendez, Emilio
Pleska, Zachary
Sako, Kelsey
Amiri, Amirnezam
Barnes, Ashley T.
Boquien, Médéric
Chandar, Rupali
Chown, Ryan
Gnedin, Oleg Y.
Grasha, Kathryn
Hannon, Stephen
Hassani, Hamid
Indebetouw, Rémy
Kim, Hwihyun
Kim, Jaeyeon
Koziol, Hannah
Larson, Kirsten L.
Lee, Janice C.
Leroy, Adam K.
Oakes, Elias K.
Rodríguez, M. Jimena
Rosolowsky, Erik
Sandstrom, Karin
Schinnerer, Eva
Sutter, Jessica
Thilker, David A.
Ubeda, Leonardo
Whitmore, Bradley C.
Weinbeck, Tony D.
Williams, Thomas G.
Wofford, Aida
Méndez-Delgado, J. Eduardo
Tian, Qiushi Chris
Collaboration, the PHANGS
contents The joint capabilities of the Hubble Space Telescope (HST) and JWST allow for an unparalleled look at the early lives of star clusters at near- and mid-infrared wavelengths. We present here a multiband analysis of embedded young stellar clusters in 11 nearby, star-forming galaxies, using the PHANGS-JWST and PHANGS-HST datasets. We use the Zooniverse citizen science platform to conduct an initial by-eye search for embedded clusters in near-UV/optical/near-infrared images that trace stellar continuum emission, the Paschen$α$ and H$α$ recombination lines, and the 3.3 $μ$m polycyclic aromatic hydrocarbon feature and its underlying continuum. With this approach, we identify 292 embedded cluster candidates for which we characterize their ages, masses, and levels of line-of-sight extinction by comparing the photometric data to predictions from stellar population models. The embedded cluster candidates have a median age of 4.5 Myr and an average line-of-sight extinction $\left< A_V \right> = 6.0$ mag. We determine lower limits on source stellar masses, resulting in a median stellar mass of $10^3$ $M_{\odot}$. We use this sample of embedded cluster candidates to train multiple convolutional neural network models to carry out deep transfer learning-based searches for embedded clusters. With the aim of optimizing models for future catalog production, we compare results for four variations of training data using two neural networks. Confusion matrices for all eight model configurations, as well as inter-model identification trends, are presented. With refinement of the training sample, we determine that optimized models could serve as a pathway for future embedded cluster identification beyond our 11 galaxy sample.
format Preprint
id arxiv_https___arxiv_org_abs_2511_11920
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle PAH Marks the Spot: Digging for Buried Clusters in Nearby Star-forming Galaxies
Graham, Gabrielle B.
Dale, Daniel A.
Smith, Chase L.
Brann, Elisabeth
Conder, Kaycee D.
Crowe, Samuel
Dhileepkumar, Sumitra
Imming, Nicole A.
Mendez, Emilio
Pleska, Zachary
Sako, Kelsey
Amiri, Amirnezam
Barnes, Ashley T.
Boquien, Médéric
Chandar, Rupali
Chown, Ryan
Gnedin, Oleg Y.
Grasha, Kathryn
Hannon, Stephen
Hassani, Hamid
Indebetouw, Rémy
Kim, Hwihyun
Kim, Jaeyeon
Koziol, Hannah
Larson, Kirsten L.
Lee, Janice C.
Leroy, Adam K.
Oakes, Elias K.
Rodríguez, M. Jimena
Rosolowsky, Erik
Sandstrom, Karin
Schinnerer, Eva
Sutter, Jessica
Thilker, David A.
Ubeda, Leonardo
Whitmore, Bradley C.
Weinbeck, Tony D.
Williams, Thomas G.
Wofford, Aida
Méndez-Delgado, J. Eduardo
Tian, Qiushi Chris
Collaboration, the PHANGS
Astrophysics of Galaxies
The joint capabilities of the Hubble Space Telescope (HST) and JWST allow for an unparalleled look at the early lives of star clusters at near- and mid-infrared wavelengths. We present here a multiband analysis of embedded young stellar clusters in 11 nearby, star-forming galaxies, using the PHANGS-JWST and PHANGS-HST datasets. We use the Zooniverse citizen science platform to conduct an initial by-eye search for embedded clusters in near-UV/optical/near-infrared images that trace stellar continuum emission, the Paschen$α$ and H$α$ recombination lines, and the 3.3 $μ$m polycyclic aromatic hydrocarbon feature and its underlying continuum. With this approach, we identify 292 embedded cluster candidates for which we characterize their ages, masses, and levels of line-of-sight extinction by comparing the photometric data to predictions from stellar population models. The embedded cluster candidates have a median age of 4.5 Myr and an average line-of-sight extinction $\left< A_V \right> = 6.0$ mag. We determine lower limits on source stellar masses, resulting in a median stellar mass of $10^3$ $M_{\odot}$. We use this sample of embedded cluster candidates to train multiple convolutional neural network models to carry out deep transfer learning-based searches for embedded clusters. With the aim of optimizing models for future catalog production, we compare results for four variations of training data using two neural networks. Confusion matrices for all eight model configurations, as well as inter-model identification trends, are presented. With refinement of the training sample, we determine that optimized models could serve as a pathway for future embedded cluster identification beyond our 11 galaxy sample.
title PAH Marks the Spot: Digging for Buried Clusters in Nearby Star-forming Galaxies
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2511.11920