J/MNRAS/454/1886   Galaxy morphologies with Illustris Simulation (Snyder+, 2015)
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Galaxy morphology and star formation in the Illustris Simulation at z = 0.
    Snyder G.F., Torrey P., Lotz J.M., Genel S., Mcbride C.K., Vogelsberger M.,
    Pillepich A., Nelson D., Sales L.V., Sijacki D., Hernquist L., Springel V.
   <Mon. Not. R. Astron. Soc., 454, 1886-1908 (2015)>
   =2015MNRAS.454.1886S    (SIMBAD/NED BibCode)
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ADC_Keywords: Models ; Galaxy catalogs ; Morphology
Keywords: methods: numerical - galaxies: formation - galaxies: statistics -
          galaxies: structure

Abstract:
    We study how optical galaxy morphology depends on mass and star
    formation rate (SFR) in the Illustris Simulation. To do so, we measure
    automated galaxy structures in 10808 simulated galaxies at z=0 with
    stellar masses 109.7<M*/M_{sun}_< 1012.3. We add observational realism
    to idealized synthetic images and measure non-parametric statistics in
    rest-frame optical and near-IR images from four directions. We find
    that Illustris creates a morphologically diverse galaxy population,
    occupying the observed bulge strength locus and reproducing median
    morphology trends versus stellar mass, SFR, and compactness.
    Morphology correlates realistically with rotation, following
    classification schemes put forth by kinematic surveys. Type fractions
    as a function of environment agree roughly with data. These results
    imply that connections among mass, star formation, and galaxy
    structure arise naturally from models matching global star formation
    and halo occupation functions when simulated with accurate methods.
    This raises a question of how to construct experiments on galaxy
    surveys to better distinguish between models. We predict that at fixed
    halo mass near 10^12^M_{sun}_, disc-dominated galaxies have higher
    stellar mass than bulge-dominated ones, a possible consequence of the
    Illustris feedback model. While Illustris galaxies at
    M*~10^11^M_{sun}_ have a reasonable size distribution, those at
    M*~10^10^M_{sun}_ have half-light radii larger than observed by a
    factor of 2. Furthermore, at M*~10^10.5^-10^11^M_{sun}_, a relevant
    fraction of Illustris galaxies have distinct 'ring-like' features,
    such that the bright pixels have an unusually wide spatial extent.

Description:
    The Illustris Project consists of hydrodynamical simulations of galaxy
    formation in a periodic volume of size (106.5Mpc)^3^ (Genel et al.
    2014MNRAS.445..175G; Vogelsberger et al., 2014MNRAS.444.1518V,
    2014Natur.509..177V).

    The Illustris simulations are publicly available at
    www.illustris-project.org/data (Nelson et al., 2015, preprint
    (arXiv:1504.00362)).

    We generate noiseless high-resolution images with an approach
    described by Torrey et al. (2015MNRAS.448...59N) built around the
    sunrise3 code (Jonsson, 2006MNRAS.372....2J; Jonsson & Primack,
    2010NewA...15..509J; Jonsson, Groves & Cox, 2010MNRAS.403...17J).

File Summary:
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 FileName      Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe            80        .   This file
gfs_u.dat         57    42531   SDSS-like sources for 10808 simulated galaxies
                                 in rest-frame u filter
gfs_g.dat         57    42531   SDSS-like sources for 10808 simulated galaxies
                                 in rest-frame g filter
gfs_i.dat         57    42531   SDSS-like sources for 10808 simulated galaxies
                                 in rest-frame i filter
gfs_h.dat         57    42531   SDSS-like sources for 10808 simulated galaxies
                                 in rest-frame H filter
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See also:
   J/AJ/128/163 : Galaxy morphological classification (Lotz+, 2004)

Byte-by-byte Description of file: gfs_g.dat gfs_h.dat gfs_i.dat gfs_u.dat
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   Bytes Format Units   Label     Explanations
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       1  A1    ---     Band      [Hgiu] Band
   3-  8  I6    ---     Index     Illustris Simulation subhalo index for
                                   snapshot 135 (z=0)
  10- 14  F5.2  [Msun]  logM*     Log10 of stellar mass within 2x stellar
                                   half-mass radius (fiducial M_* from
                                   Vogelsberger et al., 2014MNRAS.444.1518V)
  16- 20  F5.2  Msun/yr SFR       Star formation rate in subhalo
  22- 25  F4.2  mag     U-B       Intrinsic U-B color (AB system, Johnson
                                    filters) of subhalo, dust-free
      27  I1    ---     Cam       Camera number from 2013 Sunrise run
  29- 32  F4.2  ---     Gini      Gini, following Lotz et al.
                                   (2004, Cat. J/AJ/128/163)
  34- 38  F5.2  ---     M20       M20, following Lotz et al.
                                   (2004, Cat. J/AJ/128/163)
  40- 43  F4.2  ---     C         ? Concentration, following Lotz et al.
                                   (2004, Cat. J/AJ/128/163)
      44  A1    ---   n_C         [i] i for infinity
  46- 51  F6.2  kpc     Rpetro    Elliptical Petrosian radius, following
                                   Lotz et al. (2004, Cat. J/AJ/128/163)
  53- 57  F5.2  kpc     rhl       Elliptical half-light radius, following
                                   Lotz et al. (2004, Cat. J/AJ/128/163)
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History:
    From electronic version of the journal

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(End)                                      Patricia Vannier [CDS]    29-Jun-2016