Dynamical Family Properties and Dark Halo Scaling Relations of Giant Elliptical Galaxies

By O. Gerhard, A. Kronawitter, R. Saglia, R. Bender. 2000

403 citations recorded by the source corpus.

Based on a uniform dynamical analysis of the line-profile shapes of 21 mostly luminous, slowly rotating, and nearly round elliptical galaxies, we have investigated the dynamical family relations and dark halo properties of ellipticals. Our results include: (i) The circular velocity curves (CVCs) of elliptical galaxies are flat to within ≃10% for R ≳ 0.2Re. (ii) Most ellipticals are moderately radially anisotropic; their dynamical structure is surprisingly uniform. (iii) Elliptical galaxies follow a Tully-Fisher (TF) relation with marginally shallower slope than spiral galaxies, and v ≃ 300 km s-1 for an L galaxy. At given circular velocity, they are ∼1 mag fainter in B and ∼0.6 mag in R and appear to have slightly lower baryonic mass than spirals, even for the maximum M/LB allowed by the kinematics. (iv) The luminosity dependence of M/LB indicated by the tilt of the fundamental plane (FP) is confirmed. The tilt of the FP is not caused by dynamical or photometric nonhomology, although the latter might influence the slope of M/L versus L. It can also not be due only to an increasing dark matter fraction with L for the range of IMF currently discussed. It is, however, consistent with stellar population models based on published metallicities and ages. The main driver is therefore probably metallicity, and a secondary population effect is needed to explain the K-band tilt. (v) These results make it likely that elliptical galaxies have nearly maximal M/LB (minimal halos). (vi) Despite the uniformly flat CVCs, there is a spread in the luminous to dark matter ratio and in cumulative M/LB(r). Some galaxies have no indication for dark matter within 2Re, whereas for others we obtain local M/LB-values of 20–30 at 2Re. (vii) In models with maximum stellar mass, the dark matter contributes ∼10%–40% of the mass within Re. Equal interior mass of dark and luminous matter is predicted at ∼2–4Re. (viii) Even in these maximum stellar mass models, the halo core densities and phase-space densities are at least ∼25 times larger and the halo core radii ∼4 times smaller than in spiral galaxies of the same circular velocity. The increase in M/L sets in at ∼10 times larger acceleration than in spirals. This could imply that elliptical galaxy halos collapsed at high redshifts or that some of the dark matter in ellipticals might be baryonic.

Subfields: Astronomy and Astrophysics, Instrumentation

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In Astronomy and Astrophysics

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Citations in the corpus

• How do minor mergers promote inside-out growth of ellipticals, transforming the size, density profile and dark matter fraction? (2012, background): “There is evidence for the presence of dark matter in present day massive ellipticals, however the exact amount is uncertain (Gerhard et al. 2001; Thomas et al. 2009, 2011; Cappellari 2012a).”
• The internal structure of the lens PG1115+080: breaking degeneracies in the value of the Hubble constant (2002, background): “…given the intrinsic scatter in the total mss profile and fraction of dark matter in the central 1–2 Re of E/S0 galaxies (see e.g., Bertin et al. 1994; Carollo et al. 1995; Gerhard et al. 2001, for ranges of mass profiles of E/S0 galaxies), particularly if there is evidence for offsets from the FP.”
• The Sloan Lens ACS Survey. IV. The Mass Density Profile of Early-Type Galaxies out to 100 Effective Radii (2007, background): “…2005) for the passive evolution of massive early-type galaxies, we get a redshift zero B band stellar mass-to-light ratio ∼ 5.81 ± 0.61 which is statistically consistent with local estimates such as ΥB = 7.8± 2.7 and ΥB = 7.1± 2.8 from Gerhard et al. (2001) and Trujillo et al. (2004) respectively.”
• Probing Dark Matter Substructure in Lens Galaxies (2001, methodology): “An isothermal profile for the total mass distribution of elliptical galaxies is well supported by the detailed dynamical studies of local ellipticals (Gerhard et al. 2001), individual lens modeling, and statistics (e.g. Maoz & Rix 1993; Kochanek 1995; Grogin & Narayan 1996).”
• STRUCTURE AND FORMATION OF ELLIPTICAL AND SPHEROIDAL GALAXIES (2008, methodology): “They include additionalM/L values based on three-integral models (Gebhardt et al. 2003, 2007; Thomas et al. 2007), two-integral models of galaxies observed to very large radii (Kronawitter et al. 2000; Gerhard et al. 2001), and two-integral models of large galaxy samples (e. g., van der Marel 1991).”
• Submillimeter Galaxies at z ~ 2: Evidence for Major Mergers and Constraints on Lifetimes, IMF, and CO-H2 Conversion Factor (2008, background): “2, motivated by the findings in the local universe (Gerhard et al. 2001; Kassin et al. 2006).”
• Triaxial orbit based galaxy models with an application to the (apparent) decoupled core galaxy NGC 4365 (2007, background): “…et al. 2005; Shapiro et al. 2006; van den Bosch et al. 2006), to deduce the properties of dark haloes (e.g. Rix et al. 1997; Cretton et al. 1999; Gerhard et al. 2001; Thomas et al. 2005), and to derive the internal orbital structure and intrinsic shape (Cappellari et al. 2002; Verolme et al.…”
• Two-dimensional kinematics of SLACS lenses – III. Mass structure and dynamics of early-type lens galaxies beyond z ≃ 0.1 (2011, background): “…(see e.g. Saglia, Bertin, & Stiavelli 1992, Bertin et al. 1994, Franx et al. 1994, Carollo et al. 1995, Rix et al. 1997, Loewenstein & White 1999, Gerhard et al. 2001, Borriello et al. 2003, van den Bosch et al. 2008, Thomas et al. 2007, 2009, 2011 and in particular the SAURON project, de Zeeuw…”
• Stellar and dynamical masses of ellipticals in the Sloan Digital Sky Survey (2003, background): “However, based on detailed dynamical measurements of nearby ellipticals, Gerhard et al. (2001) argue that there is little evidence for any deviations from homology.”
• THE INITIAL MASS FUNCTION OF EARLY-TYPE GALAXIES (2010, positive): “As we will discuss further below, none of the results of this paper is changed if Jaffe or moderately anisotropic models (β = ±0.25)– consistent with independent constraints on anisotropy (e.g. Gerhard et al. 2001) – are considered instead.”
• Supermassive Black Holes in Galactic Nuclei: Past, Present and Future Research (2004, methodology): “For the elliptical galaxies, the circular velocity is derived from dynamical models applied to the stellar kinematics (Gerhard et al. 2001; Kronawitter et al. 2000).”
• Red mergers and the assembly of massive elliptical galaxies: the fundamental plane and its projections (2006, background): “…as possible origins for the tilt of the fundamental plane (e.g. Faber et al. 1987; Ciotti et al. 1996; Graham & Colless 1997; Pahre et al. 1998a; Gerhard et al. 2001; Padmanabhan et al. 2004; Trujillo, Burkert & Bell 2004a), it is useful to assess the importance of non-homology in the context…”
• Dark matter in elliptical galaxies — II. Estimating the mass within the virial radius (2004, background): “…of SDSSgalaxies, Guzik & Seljak (2002) find thatL∗ galaxies have mass-to-light ratio Υ of order of 100 in theB band, again implying substantial dark matter, since the stellar contribution to the mass-to-light ratio is thought to be onlyΥ∗ ≃ 8 in the blue band (see e.g. Gerhard et al. 2001).”
• THE SLOAN LENS ACS SURVEY. X. STELLAR, DYNAMICAL, AND TOTAL MASS CORRELATIONS OF MASSIVE EARLY-TYPE GALAXIES (2010, methodology): “0.5, consistent with Gerhard et al. 2001) is sufficient to produce an isothermal slope, γ′0 = 2.”
• TDCOSMO IV: Hierarchical time-delay cosmography -- joint inference of the Hubble constant and galaxy density profiles (2020, background): “Observations suggest that typical massive elliptical galaxies are, in their central regions, isotropic or mildly radially anisotropic (e.g., Gerhard et al. 2001; Cappellari et al. 2007); similarly, different theoretical models of galaxy formation predict that elliptical galaxies should have…”