J/MNRAS/454/1886 Galaxy morphologies with Illustris Simulation (Snyder+, 2015)
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 2015MNRAS.454.1886S (SIMBAD/NED BibCode)
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☉< 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 1012M☉, disc-dominated galaxies have higher
stellar mass than bulge-dominated ones, a possible consequence of the
Illustris feedback model. While Illustris galaxies at
M*∼1011M☉ have a reasonable size distribution, those at
M*∼1010M☉ have half-light radii larger than observed by a
factor of 2. Furthermore, at M*∼1010.5-1011M☉, 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 2014MNRAS.445..175G; Vogelsberger et al., 2014MNRAS.444.1518V 2014MNRAS.444.1518V,
2014Natur.509..177V 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 2015MNRAS.448...59N) built around the
sunrise3 code (Jonsson, 2006MNRAS.372....2J 2006MNRAS.372....2J; Jonsson & Primack,
2010NewA...15..509J 2010NewA...15..509J; Jonsson, Groves & Cox, 2010MNRAS.403...17J 2010MNRAS.403...17J).
File Summary:
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FileName Lrecl Records Explanations
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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
--------------------------------------------------------------------------------
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 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
(End) Patricia Vannier [CDS] 29-Jun-2016