TY - JOUR
T1 - Bright, relatively isolated star clusters in PHANGS-HST galaxies
T2 - Aperture corrections, quantitative morphologies, and comparison with synthetic stellar population models
AU - Deger, Sinan
AU - Lee, Janice C.
AU - Whitmore, Bradley C.
AU - Thilker, David A.
AU - Boquien, Mederic
AU - Chandar, Rupali
AU - Dale, Daniel A.
AU - Ubeda, Leonardo
AU - White, Rick
AU - Grasha, Kathryn
AU - Glover, Simon C.O.
AU - Schruba, Andreas
AU - Barnes, Ashley T.
AU - Klessen, Ralf
AU - Kruijssen, J. M.DIederik
AU - Rosolowsky, Erik
AU - Williams, Thomas G.
N1 - Publisher Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
PY - 2022/2/1
Y1 - 2022/2/1
N2 - Using PHANGS-HST NUV-U-B-V-I imaging of 17 nearby spiral galaxies, we study samples of star clusters and stellar associations, visually selected to be bright and relatively isolated, for three purposes: to compute aperture corrections for star cluster photometry, to explore the utility of quantitative morphologies in the analysis of clusters and associations, and to compare to synthetic stellar population models. We provide a technical summary of our procedures to determine aperture corrections, a standard step in the production of star cluster candidate catalogues, and compare to prior work. We also use this specialized sample to launch an analysis into the measurement of star cluster light profiles. We focus on one measure, M20 (normalized second-order moment of the brightest 20 per cent of pixels), applied previously to study the morphologies of galaxies. We find that M20 in combination with UB-VI colours, yields a parameter space where distinct loci are formed by single-peaked symmetric clusters, single-peaked asymmetric clusters, and multipeaked associations. We discuss the potential applications for using M20 to gain insight into the formation and evolution of clusters and associations. Finally, we compare the colour distributions of this sample with various synthetic stellar population models. One finding is that the standard procedure of using a single-metallicity SSP track to fit the entire population of clusters in a given galaxy should be revisited, as the oldest globular clusters will be more metal-poor compared to clusters formed recently.
AB - Using PHANGS-HST NUV-U-B-V-I imaging of 17 nearby spiral galaxies, we study samples of star clusters and stellar associations, visually selected to be bright and relatively isolated, for three purposes: to compute aperture corrections for star cluster photometry, to explore the utility of quantitative morphologies in the analysis of clusters and associations, and to compare to synthetic stellar population models. We provide a technical summary of our procedures to determine aperture corrections, a standard step in the production of star cluster candidate catalogues, and compare to prior work. We also use this specialized sample to launch an analysis into the measurement of star cluster light profiles. We focus on one measure, M20 (normalized second-order moment of the brightest 20 per cent of pixels), applied previously to study the morphologies of galaxies. We find that M20 in combination with UB-VI colours, yields a parameter space where distinct loci are formed by single-peaked symmetric clusters, single-peaked asymmetric clusters, and multipeaked associations. We discuss the potential applications for using M20 to gain insight into the formation and evolution of clusters and associations. Finally, we compare the colour distributions of this sample with various synthetic stellar population models. One finding is that the standard procedure of using a single-metallicity SSP track to fit the entire population of clusters in a given galaxy should be revisited, as the oldest globular clusters will be more metal-poor compared to clusters formed recently.
KW - galaxies: star clusters: general
KW - galaxies: star formation
UR - http://www.scopus.com/inward/record.url?scp=85126640326&partnerID=8YFLogxK
U2 - 10.1093/mnras/stab3213
DO - 10.1093/mnras/stab3213
M3 - Article
SN - 0035-8711
VL - 510
SP - 32
EP - 53
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -