Showing papers by "S. L. Lu published in 2019"
TL;DR: In this paper, the authors derived the mass-weighted total density slopes within the effective (half-light) radius, γ′, for more than 2000 nearby galaxies from the SDSS-IV (Sloan Digital Sky Survey IV) MaNGA survey using Jeans-anisotropic-models applied to integral field unit observations.
Abstract: We derive the mass-weighted total density slopes within the effective (half-light) radius, γ′, for more than 2000 nearby galaxies from the SDSS-IV (Sloan Digital Sky Survey IV) MaNGA survey using Jeans-anisotropic-models applied to integral field unit observations. Our galaxies span a wide range of the stellar mass (109 M⊙ 100 km s−1, the density slope has a mean value 〈γ′〉 = 2.24 and a dispersion σγ = 0.22, almost independent of velocity dispersion, consistent with previous lensing and stellar dynamical analysis. We also quantitatively confirm with high accuracy a turnover in the γ′–σv relation is present at σ ∼ 100 km s−1, below which the density slope decreases rapidly with σv, consistent with the results reported by previous analysis of ATLAS3D survey. Our analysis shows that a large fraction of dwarf galaxies (below M* = 1010 M⊙) have total density slopes shallower than 1, which implies that they may reside in cold dark matter haloes with shallow density slopes. We compare our results with that of galaxies in hydrodynamical simulations of EAGLE, Illustris, and IllustrisTNG projects, and find all simulations predict shallower density slopes for massive galaxies with high σv. Finally, we explore the dependence of γ′ on the positions of galaxies in haloes, namely centrals versus satellites, and find that for the same velocity dispersion, the amplitude of γ′ is higher for satellite galaxies by about 0.1.
17 citations
Tsinghua University1, Chinese Academy of Sciences2, Max Planck Society3, University of Vienna4, York University5, Columbia University6, National Autonomous University of Mexico7, Harvard University8, University of Bologna9, Massachusetts Institute of Technology10, University of Florida11, University of Illinois at Urbana–Champaign12
TL;DR: In this paper, the authors make use of a comparable galaxy sample at z = 0 with a stellar mass range from 5E9 to 5E11 solar masses, selected from the IllustrisTNG simulation and study their stellar orbit compositions in relation to a number of other fundamental galaxy properties.
Abstract: Motivated by the recently discovered kinematic "Hubble sequence" shown by the stellar orbit-circularity distribution of 260 CALIFA galaxies, we make use of a comparable galaxy sample at z = 0 with a stellar mass range from 5E9 to 5E11 solar masses, selected from the IllustrisTNG simulation and study their stellar orbit compositions in relation to a number of other fundamental galaxy properties.We find that the TNG100 simulation broadly reproduces the observed fractions of different orbital components and their stellar mass dependencies. In particular, the mean mass dependencies of the luminosity fractions for the kinematically warm and hot orbits are well reproduced within model uncertainties of the observed galaxies. The simulation also largely reproduces the observed peak and trough features at a stellar mass of 1-2E10 solar masses, in the mean distributions of the cold- and hot-orbit fractions, respectively, indicating fewer cooler orbits and more hotter orbits in both more- and less-massive galaxies beyond such a mass range. Several marginal disagreements are seen between the simulation and observations: the average cold-orbit (counter-rotating) fractions of the simulated galaxies below (above) a stellar mass of 6E10 solar masses, are systematically higher than the observational data by < 10% (absolute orbital fraction); the simulation also seems to produce more scatter for the cold-orbit fraction and less so for the non-cold orbits at any given galaxy mass. Possible causes that stem from the adopted heating mechanisms are discussed.
17 citations