Speaker
Description
We employ a recently-developed population-orbit superposition technique to simultaneously fit the stellar kinematic and age maps of 82 CALIFA spiral galaxies, and obtain the ages of stars in different dynamical structures. We first evaluate the capabilities of this method on CALIFA-like mock data created from the Auriga simulations. The recovered mean ages of dynamically cold, warm and hot components match the true values well, with up to $20\%$ observational error in the mock age maps. For CALIFA spiral galaxies, we find that the stellar ages of the cold, warm and hot components all increase with galaxies' stellar mass, from $\overline{t_{\rm cold}}\sim2.2$ Gyr, $\overline{t_{\rm warm}}\sim2.3$ Gyr and $\overline{t_{\rm hot}}\sim2.6$ Gyr for galaxies with stellar mass $M_*<10^{10}\,\rm M_{\odot}$, to $\overline{t_{\rm cold}}\sim4.0$ Gyr, $\overline{t_{\rm warm}}\sim5.1$ Gyr and $\overline{t_{\rm hot}}\sim5.9$ Gyr for galaxies with $M_*>10^{11}\,\rm M_{\odot}$. About $80\%$ of the galaxies in our sample have $t_{\rm hot}>t_{\rm cold}$, and the mean values of $t_{\rm hot}-t_{\rm cold}$ also increase with stellar mass, from $0.7_{-0.2}^{+0.6}$ Gyr in low-mass galaxies ($10^{8.9}\,\rm M_{\odot}
