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SDSS-IV MaNGA: global stellar population and gradients for about 2000 early-type and spiral galaxies on the mass-size plane

Research output: Contribution to journalArticle

  • Hongyu Li
  • Shude Mao
  • Michele Cappellari
  • Junqiang Ge
  • R. J. Long
  • Ran Li
  • H. J. Mo
  • Cheng Li
  • Zheng Zheng
  • Kevin Bundy
  • Professor Daniel Thomas
  • Joel R. Brownstein
  • Alexandre Roman Lopes
  • David R. Law
  • Niv Drory
We perform full spectrum fitting stellar population analysis and Jeans Anisotropic modelling of the stellar kinematics for about 2000 early-type galaxies (ETGs) and spiral galaxies from the MaNGA DR14 sample. Galaxies with different morphologies are found to be located on a remarkably tight mass plane which is close to the prediction of the virial theorem, extending previous results for ETGs. By examining an inclined projection (‘the mass–size’ plane), we find that spiral and early-type galaxies occupy different regions on the plane, and their stellar population properties (i.e. age, metallicity, and stellar mass-to-light ratio) vary systematically along roughly the direction of velocity dispersion, which is a proxy for the bulge fraction. Galaxies with higher velocity dispersions have typically older ages, larger stellar mass-to-light ratios and are more metal rich, which indicates that galaxies increase their bulge fractions as their stellar populations age and become enriched chemically. The age and stellar mass-to-light ratio gradients for low-mass galaxies in our sample tend to be positive (centre < outer), while the gradients for most massive galaxies are negative. The metallicity gradients show a clear peak around velocity dispersion log10 σe ≈ 2.0, which corresponds to the critical mass ∼3 × 1010 M⊙ of the break in the mass–size relation. Spiral galaxies with large mass and size have the steepest gradients, while the most massive ETGs, especially above the critical mass Mcrit ≳ 2 × 1011 M⊙, where slow rotator ETGs start dominating, have much flatter gradients. This may be due to differences in their evolution histories, e.g. mergers.
Original languageEnglish
Pages (from-to)1765-1775
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume476
Issue number2
Early online date9 Feb 2018
DOIs
Publication statusPublished - 11 May 2018

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    Rights statement: This article has been accepted for publication in MNRAS © 2018 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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