TY - JOUR
T1 - PHANGS-JWST First Results
T2 - A Combined HST and JWST Analysis of the Nuclear Star Cluster in NGC 628
AU - Hoyer, Nils
AU - Pinna, Francesca
AU - Kamlah, Albrecht W.H.
AU - Nogueras-Lara, Francisco
AU - Feldmeier-Krause, Anja
AU - Neumayer, Nadine
AU - Sormani, Mattia C.
AU - Boquien, Médéric
AU - Emsellem, Eric
AU - Seth, Anil C.
AU - Klessen, Ralf S.
AU - Williams, Thomas G.
AU - Schinnerer, Eva
AU - Barnes, Ashley T.
AU - Leroy, Adam K.
AU - Bonoli, Silvia
AU - Kruijssen, J. M.Diederik
AU - Neumann, Justus
AU - Sánchez-Blázquez, Patricia
AU - Dale, Daniel A.
AU - Watkins, Elizabeth J.
AU - Thilker, David A.
AU - Rosolowsky, Erik
AU - Bigiel, Frank
AU - Grasha, Kathryn
AU - Egorov, Oleg V.
AU - Liu, Daizhong
AU - Sandstrom, Karin M.
AU - Larson, Kirsten L.
AU - Blanc, Guillermo A.
AU - Hassani, Hamid
N1 - Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/2/1
Y1 - 2023/2/1
N2 - We combine archival Hubble Space Telescope and new James Webb Space Telescope imaging data covering the ultraviolet to mid-infrared regime to morphologically analyze the nuclear star cluster (NSC) of NGC 628, a grand-design spiral galaxy. The cluster is located in a 200 pc × 400 pc cavity lacking both dust and gas. We find roughly constant values for the effective radius (r eff ∼ 5 pc) and ellipticity (ϵ ∼ 0.05), while the Sérsic index (n) and position angle (PA) drop from n ∼ 3 to ∼2 and PA ∼ 130° to 90°, respectively. In the mid-infrared, r eff ∼ 12 pc, ϵ ∼ 0.4, and n ∼ 1-1.5, with the same PA ∼ 90°. The NSC has a stellar mass of log 10 ( M ⋆ nsc / M ⊙ ) = 7.06 ± 0.31 , as derived through B − V, confirmed when using multiwavelength data, and in agreement with the literature value. Fitting the spectral energy distribution (SED), excluding the mid-infrared data, yields a main stellar population age of (8 ± 3) Gyr with a metallicity of Z = 0.012 ± 0.006. There is no indication of any significant star formation over the last few gigayears. Whether gas and dust were dynamically kept out or evacuated from the central cavity remains unclear. The best fit suggests an excess of flux in the mid-infrared bands, with further indications that the center of the mid-infrared structure is displaced with respect to the optical center of the NSC. We discuss five potential scenarios, none of them fully explaining both the observed photometry and structure.
AB - We combine archival Hubble Space Telescope and new James Webb Space Telescope imaging data covering the ultraviolet to mid-infrared regime to morphologically analyze the nuclear star cluster (NSC) of NGC 628, a grand-design spiral galaxy. The cluster is located in a 200 pc × 400 pc cavity lacking both dust and gas. We find roughly constant values for the effective radius (r eff ∼ 5 pc) and ellipticity (ϵ ∼ 0.05), while the Sérsic index (n) and position angle (PA) drop from n ∼ 3 to ∼2 and PA ∼ 130° to 90°, respectively. In the mid-infrared, r eff ∼ 12 pc, ϵ ∼ 0.4, and n ∼ 1-1.5, with the same PA ∼ 90°. The NSC has a stellar mass of log 10 ( M ⋆ nsc / M ⊙ ) = 7.06 ± 0.31 , as derived through B − V, confirmed when using multiwavelength data, and in agreement with the literature value. Fitting the spectral energy distribution (SED), excluding the mid-infrared data, yields a main stellar population age of (8 ± 3) Gyr with a metallicity of Z = 0.012 ± 0.006. There is no indication of any significant star formation over the last few gigayears. Whether gas and dust were dynamically kept out or evacuated from the central cavity remains unclear. The best fit suggests an excess of flux in the mid-infrared bands, with further indications that the center of the mid-infrared structure is displaced with respect to the optical center of the NSC. We discuss five potential scenarios, none of them fully explaining both the observed photometry and structure.
UR - http://www.scopus.com/inward/record.url?scp=85148768874&partnerID=8YFLogxK
U2 - 10.3847/2041-8213/aca53e
DO - 10.3847/2041-8213/aca53e
M3 - Article
SN - 2041-8205
VL - 944
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L25
ER -