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.

arXiv comment20 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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