Morphology and kinematics of orbital components in CALIFA galaxies across the Hubble sequence

Zhu, Ling; Ven, Glenn van de; Mendez-Abreu, Jairo und Obreja, Aura (2018): Morphology and kinematics of orbital components in CALIFA galaxies across the Hubble sequence. In: Monthly Notices of the Royal Astronomical Society, Bd. 479, Nr. 1: S. 945-960

Abstract

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 (Sigma) 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(0.1Re)/Sigma(Re) ) and intrinsic flattening q(Re) and q(Rmax) , with R-e the half-light-radius and R-max 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 disk-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 f(cold) is well correlated with the photometrically-decomposed disk fraction f(disk) as f(cold) =0.14+0.23 f(disk). Similarly, the hot orbit fraction f(hot) is correlated with the bulge fraction f(bulge) as f(hot) =0.19+0.31 f(bulge). The warm orbits mainly contribute to disks 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 (epsilon=1 - q(Rmax)) versus kinematics (sigma(2)(z)/V-tot((2) over bar)) relation as the thin disk, thick disk/pseudo bulge, and classical bulge identified from cosmological simulations.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 0035-8711
• Sprache: Englisch