Galaxy properties as revealed by MaNGA. III. Kinematic profiles and stellar population gradients in S0s

Abstract

This is the third paper of a series where we study the stellar population gradients (SP; ages, metallicities, $\alpha$-element abundance ratios and stellar initial mass functions) of early type galaxies (ETGs) at $z\le 0.08$ from the MaNGA-DR15 survey. In this work we focus on the S0 population and quantify how the SP varies across the population as well as with galactocentric distance. We do this by measuring Lick indices and comparing them to stellar population synthesis models. This requires spectra with high signal-to-noise which we achieve by stacking in bins of luminosity (L${}_r$) and central velocity dispersion (${\sigma }_0$). We find that: 1) There is a bimodality in the S0 population: S0s more massive than $3\times 10^{10}{M}_{\odot }$ show stronger velocity dispersion and age gradients (age and ${\sigma }_r$ decrease outwards) but little or no metallicity gradient, while the less massive ones present relatively flat age and velocity dispersion profiles, but a significant metallicity gradient (i.e. [M/H] decreases outwards). Above $2\times 10^{11}{M}_{\odot }$ the number of S0s drops sharply. These two mass scales are also where global scaling relations of ETGs change slope. 2) S0s have steeper velocity dispersion profiles than fast rotating elliptical galaxies (E-FRs) of the same luminosity and velocity dispersion. The kinematic profiles and stellar population gradients of E-FRs are both more similar to those of slow rotating ellipticals (E-SRs) than to S0s, suggesting that E-FRs are not simply S0s viewed face-on. 3) At fixed ${\sigma }_0$, more luminous S0s and E-FRs are younger, more metal rich and less $\alpha$-enhanced. Evidently for these galaxies, the usual statement that 'massive galaxies are older' is not true if ${\sigma }_0$ is held fixed.

Accepted for publication in MNRAS. 15 pages, 20 figures

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• Formation of S0s in extreme environments II: the star-formation histories of bulges, discs and lenses
• BUDDI-MaNGA II: The Star-Formation Histories of Bulges and Discs of S0s
• The half mass radius of MaNGA galaxies: Effect of IMF gradients
• The Puzzling Origin of Massive Compact Galaxies in MaNGA
• The differences between mass- and light-derived structural parameters over time for MaNGA Elliptical galaxies
• The redshift evolution of the S0 fraction for $z<1$ in COSMOS
• The age gradients of galaxies in EAGLE: outside-in quenching as the origin of young bulges in cluster galaxies
• Stellar population analysis of MaNGA early-type galaxies: IMF dependence and systematic effects
• BANG-MaNGA: A census of kinematic discs and bulges across mass and star formation in the local Universe
• Stellar velocity dispersion and initial mass function gradients in dissipationless galaxy mergers
• Comparison of the Stellar Populations of Bulges and Discs using the MaNGA Survey
• The origin of star-forming rings in S0 galaxies
• The local Universe in the era of large surveys -- II. Multi-wavelength characterisation of activity in nearby S0 galaxies
• Asymmetric star formation triggered by gas inflow in a barred lenticular galaxy PGC 34107
• On the variation in stellar $\alpha$-enhancements of star-forming galaxies in the EAGLE simulation
• The Color Gradients of the Globular Cluster Systems in M87 and M49
• The distribution of lenticular galaxies in the phase space of present-day galaxy cluster regions
• J-PAS: A Neural Network Approach to Single Stellar Population Characterization
• Testing the key role of the stellar mass-halo mass relation in galaxy merger rates and morphologies via DECODE, a novel Discrete statistical sEmi-empiriCal mODEl
• Morpho-kinematic of galaxies at cosmic noon