http://arxiv.org/abs/2004.13044
We present a study on the radial profiles of D4000, luminosity-weighted stellar ages $\tau_L$ and metallicities $[Z/H]L$ of 3654 nearby galaxies ($0.01<z<0.15$) using the IFU spectroscopic data from the SDSS DR15 MaNGA data release, in an effort to explore the connection between median stellar population radial gradients (i.e., $\nabla$D4000,$\nabla\tau_L,\nabla [Z/H]_L$) out to $\sim 1.5R_e$ and various galaxy properties, including stellar mass ($M{\star}$), specific star formation rate (sSFR), morphologies and local environment. We find that $M_{\star}$ is the single most predictive physical property for $\nabla$D4000 and $\nabla [Z/H]L$. The most predictive properties for $\nabla\tau_L$ are sSFR and to a lesser degree, $M{\star}$. The environmental parameters, including local galaxy overdensities and central-satellite division, have virtually no correlation with stellar population radial profiles for whole sample, but $\nabla$D4000 of star-forming satellite galaxies with $M_{\star}\lesssim 10^{10}M_\odot$ exhibit a significant positive correlation with galaxy overdensities. Galaxies with lower sSFR have on average steeper negative stellar population gradients, and this sSFR dependence is stronger for more massive star-forming galaxies. The negative correlation between median stellar population gradients and $M_{\star}$ are best described largely as segmented relationships, whereby median gradients of galaxies with $\log M_{\star}\lesssim 10$ (with the exact value depending on sSFR) have much weaker mass dependence than galaxies with higher $M_{\star}$.While the dependence of radial gradients of ages and metallicities on T-Types and central stellar mass surface densities are generally not significant, galaxies with later T-Types or lower central mass densities tend to have significantly lower D4000, younger $\tau_L$ and lower $[Z/H]_L$ across the radial ranges probed in this study.
G. Chen, H. Zhang, X. Kong, et. al.
Wed, 29 Apr 20
41/75
Comments: 20 pages, 12 figures, accepted for publication in ApJ