Publication Date:
2018-06-11
Description:
Based on the stellar orbit distribution derived from orbit-superposition Schwarzschild models, we decompose each of 250 representative present-day galaxies into four orbital components: cold with strong rotation, warm with weak rotation, hot with dominant random motion, and counter-rotating (CR). We rebuild the surface brightness (Σ) of each orbital component and we present in figures and tables a quantification of their morphologies using the Sersic index n, concentration |$C = log {(Sigma _{0.1R_e}/Sigma _{R_e})}$| and intrinsic flattening qRe and qRmax, with Re the half-light radius and Rmax the CALIFA data coverage. We find that: (1) kinematic hotter components are generally more concentrated and rounder than colder components, and (2) all components become more concentrated and thicker/rounder in more massive galaxies; they change from disc-like in low-mass late-type galaxies to bulge-like in high-mass early type galaxies. Our findings suggest that Sersic n is not a good discriminator between rotating bulges and non-rotating bulges. The luminosity fraction of cold orbits fcold is well correlated with the photometrically decomposed disc fractiondisc |$f_{
m disc}$| as |$f_{mathrm{cold}} = 0.14 + 0.23f_{mathrm{mathrm{disc}}}$|. Similarly, the hot orbit fraction fhot is correlated with the bulge fraction fbulge as |$f_{mathrm{hot}} = 0.19 + 0.31f_{mathrm{mathrm{bulge}}}$|. The warm orbits mainly contribute to discs in low-mass late-type galaxies, and to bulges in high-mass early-type galaxies. The cold, warm, and hot components generally follow the same morphology (ε = 1 − qRmax) versus kinematics (|$sigma _z^2/overline{V_{mathrm{tot}}^2}$|) relation as the thin disc, thick disc/pseudo-bulge, and classical bulge identified from cosmological simulations.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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