The Most Predictive Physical Properties for the Stellar Population Radial Profiles of Nearby Galaxies

Guangwen Chen; Hong-Xin Zhang; Xu Kong; Zesen Lin; Zhixiong Liang; Xinkai Chen; Zuyi Chen; Zhiyuan Song

doi:10.3847/1538-4357/ab8cc2

paper

The Most Predictive Physical Properties for the Stellar Population Radial Profiles of Nearby Galaxies

arXiv:2004.13044 · doi:10.3847/1538-4357/ab8cc2

Abstract

We present a study on the radial profiles of D4000,luminosity-weighted stellar ages $τ_{L}$ ,and luminosity-weighted stellar metallicities $[Z / H]_{L}$ of 3654 nearby galaxies( $0.01 < z < 0.15$ )using the IFU spectroscopic data from the MaNGA survey available in the SDSS DR15,in an effort to explore the connection between median stellar population radial gradients( $\nabla$ D4000, $\nabla τ_{L}, \nabla [Z / H]_{L}$ )out to~ $1.5 R_{e}$ and various galaxy properties,including stellar mass( $M_{⋆}$ ),specific star formation rate(sSFR),morphologies,and local environment. We find that $M_{⋆}$ is the single most predictive physical property for $\nabla$ D4000 and $\nabla [Z / H]_{L}$ . The most predictive properties for $\nabla τ_{L}$ are sSFR,and to a lesser degree, $M_{⋆}$ . The environmental parameters,including local galaxy overdensities and central-satellite division,have virtually no correlation with stellar population radial profiles for the whole sample,but the $\nabla$ D4000 of star-forming satellite galaxies with $M_{⋆} ≲ 1 0^{10} M_{⊙}$ 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 the median stellar population gradients and $M_{⋆}$ are best described largely as segmented relationships, whereby median gradients of galaxies with $lo g M_{⋆} ≲ 10$ (with the exact value depending on sSFR)have much weaker mass dependence than galaxies with higher $M_{⋆}$ . While the dependence of the 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 $τ_{L}$ and lower $[Z / H]_{L}$ across the radial ranges probed in this study.

20 pages, 12 figures, ApJ in press

The Most Predictive Physical Properties for the Stellar Population Radial Profiles of Nearby Galaxies

Abstract

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