SCYON Abstract

Received on March 5 2018

Connections between star cluster populations and their host galaxy nuclear rings

AuthorsC. Ma (1,2), R. de Grijs (2,1,3,4), and L. C. Ho (2,1)
Affiliation(1) Department of Astronomy, Peking University, Beijing, China
(2) Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing, China;
(3) International Space Science Institute–Beijing, Beijing, China
(4) Present address: Department of Physics and Astronomy, Macquarie University, North Ryde, Australia
Accepted byAstrophysical Journal


Nuclear rings are excellent laboratories for probing diverse phenomena such as the formation and evolution of young massive star clusters (YMCs), nuclear starbursts, as well as the secular evolution and dynamics of their host galaxies. We have compiled a sample of 17 galaxies with nuclear rings, which are well resolved by high-resolution Hubble and Spitzer Space Telescope imaging. For each nuclear ring, we identified the ring star cluster population, along with their physical properties (ages, masses, extinction values). We also determined the integrated ring properties, including the average age, total stellar mass, and current star-formation rate (SFR). We find that Sb-type galaxies tend to have the highest ring stellar mass fraction with respect to the host galaxy, and this parameter is correlated with the ring's SFR surface density. The ring SFRs are correlated with their stellar masses, which is reminiscent of the main sequence of star-forming galaxies. There are striking correlations between star-forming properties (i.e., SFR and SFR surface density) and non-axisymmetric bar parameters, appearing to confirm previous inferences that strongly barred galaxies tend to have lower ring SFRs, although the ring star-formation histories turn out to be significantly more complicated. Nuclear rings with higher stellar masses tend to be associated with lower cluster mass fractions, but there is no such relation with the ages of the rings. The two youngest nuclear rings in our sample, NGC 1512 and NGC 4314, which have the most extreme physical properties, represent the young extremity of the nuclear ring age distribution.