The Structure and Dynamics of Luminous and Dark Matter in the Early-Type Lens Galaxy of 0047–281 at z = 0.485

By Leon V. E. Koopmans, T. Treu. 2002

187 citations recorded by the source corpus.

We have measured the kinematic profile of the early-type (E/S0) lens galaxy in the system 0047-281 (z = 0.485) with the Echelle Spectrograph and Imager (ESI) on the W. M. Keck II Telescope, as part of the Lenses Structure and Dynamics (LSD) Survey. The central velocity dispersion is σ = 229 ± 15 km s-1, and the dispersion profile is nearly flat to beyond one effective radius (Re). No significant streaming motion is found. Surface photometry of the lens galaxy is measured from Hubble Space Telescope images. From the offset from the local fundamental plane (FP), we measure an evolution of the effective mass-to-light ratio (M/L) of Δ log = -0.37 ± 0.06 between z = 0 and 0.485, consistent with the observed evolution of field E/S0 galaxies. (We assume h65 = 1, Ωm = 0.3, and ΩΛ = 0.7 throughout.) Gravitational lens models provide a mass of ME = × 1011 h M☉ inside the Einstein radius of RE = h kpc. This allows us to break the degeneracy between velocity anisotropy and density profile typical of dynamical models for E/S0 galaxies. We find that constant-M/L models, even with strongly tangential anisotropy of the stellar velocity ellipsoid, are excluded at more than 99.9% CL. The total mass distribution inside RE can be described by a single power-law density profile, ρt ∝ r, with an effective slope γ′ = 1.90 (68% CL; ±0.1 systematic error). Two-component models yield an upper limit (68% CL) of γ ≤ 1.55 on the power-law slope of the dark matter density profile and a projected dark matter mass fraction of 0.41(0.54)() (68% CL) inside RE, for Osipkov-Merritt models with anisotropy radius ri = ∞ . The stellar M*/L values derived from the FP agree well with the maximum allowed value from the isotropic dynamical models (i.e., the "maximum-bulge solution"). The fact that both lens systems 0047-281 (z = 0.485) and MG 2016+112 (z = 1.004) are well described inside their Einstein radii by a constant-M*/L stellar mass distribution embedded in a nearly logarithmic potential—with an isotropic or a mildly radially anisotropic dispersion tensor—could indicate that E/S0 galaxies underwent little structural evolution at z ≲ 1 and have a close-to-isothermal total mass distribution in their inner regions. Whether this conclusion can be generalized, however, requires the analysis of more systems. We briefly discuss our results in the context of E/S0 galaxy formation and cold dark matter simulations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/bd5158b1cbc83be0408b35deee75cda96866e4b5

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In Astronomy and Astrophysics

1. T. Treu
2. C. Conroy
3. F. V. D. Bosch
4. Simon D. M. White
5. H. Mo
6. P. Hopkins
7. Rachel Mandelbaum
8. M. Blanton

In Instrumentation

1. T. Treu
2. C. Conroy
3. F. V. D. Bosch
4. Simon D. M. White
5. M. Cappellari
6. H. Mo
7. Rachel Mandelbaum
8. S. More

Citations in the corpus

• Two-dimensional kinematics of SLACS lenses – III. Mass structure and dynamics of early-type lens galaxies beyond z ≃ 0.1 (2011, result): “As highlighted by these studies, as well as by a number of other works (see Treu & Koopmans 2002, Koopmans & Treu 2003, Treu & Koopmans 2004, Rusin & Kochanek 2005, Jiang & Kochanek 2007, Grillo et al. 2008, Koopmans et al. 2009, Trott et al. 2010, van de Ven et al. 2010, Dutton et al. 2011,…”
• THE INITIAL MASS FUNCTION OF EARLY-TYPE GALAXIES (2010, unknown): “The dominant parameter in determining f∗ is the inner slope of the dark matter density profile γ: steeper halos require a smaller stellar mass fraction (see, e.g., Treu & Koopmans 2002; Koopmans & Treu 2003; Treu & Koopmans 2004).”
• The Dark Matter Distribution in the Central Regions of Galaxy Clusters: Implications for Cold Dark Matter (2003, background): “Observations of spiral and early-type galaxies tend to favor inner slopes that are shallower than predicted by CDM simulations (Treu & Koopmans 2002; Koopmans & Treu 2003; Borriello & Salucci 2002; Borriello, Salucci, & Danese 2003; Jimenez, Verde & Oh 2003), although the dominance of stellar mass…”
• Are Brightest Halo Galaxies Central Galaxies (2010, background): “…kinematics (e.g., McKay et al. 2002; van den Bosch et al. 2004; More et al. 2009), weak lensing (e.g., Mandelbaum et al. 2006; Johnston et al. 2007; Cacciato et al. 2009; Sheldon et al. 2009b), and strong lensing (e.g., Kochanek 1995; Cohn et al. 2001; Koopmans & Treu 2003; Rusin et al. 2003).”
• Galaxy Masses: A Review (2013, methodology): “…has been successfully applied initially by the Lenses Structure & Dynamics (LSD) survey (e.g. Koopmans & Treu 2002; Treu & Koopmans 2002a,b; Koopmans & Treu 2003; Treu & Koopmans 2004) and more recently by the SLACS survey, the BELLS Survey (Bolton et al. 2012; Brownstein et al. 2012), the…”
• The Sloan Lens ACS Survey. IV. The Mass Density Profile of Early-Type Galaxies out to 100 Effective Radii (2007, background): “The combination of strong lensing with stellar kinematics (Treu & Koopmans 2002; Koopmans & Treu 2002, 2003; Treu & Koopmans 2004; Koopmans et al. 2006) is particularly effective, and allows one to decompose the total mass distribution into a luminous and dark matter with good precision, yielding…”
• The Evolution and Structure of Early-Type Field Galaxies: A Combined Statistical Analysis of Gravitational Lenses (2004, methodology): “…in our sample: Q2237+ 0305 (Foltz et al. 1992), MG 1549+3047 (Lehár et al. 1996), PG 1115+080 (Tonry 1998), HST 14176+5226 (Ohyama et al. 2002; Gebhardt et al. 2003; Treu & Koopmans 2004), MG 2016+112 (Koopmans & Treu 2002), 0047 281 (Koopmans & Treu 2003), and B1608+656 (Koopmans et al. 2003).”
• TWO ACCURATE TIME-DELAY DISTANCES FROM STRONG LENSING: IMPLICATIONS FOR COSMOLOGY (2012, background): “(7) Two practical approaches to overcome this degeneracy are (1) to use the stellar kinematics of the lens galaxy (e.g., Treu & Koopmans 2002, 2004; Koopmans & Treu 2003; Barnabè et al. 2009; Auger et al. 2010; Suyu et al. 2010; Sonnenfeld et al. 2012) to make an independent estimate of the lens…”
• The Sloan Lens ACS Survey. II. Stellar Populations and Internal Structure of Early-Type Lens Galaxies (2005, unknown): “Early results on the distribution of mass and light in E/S0 lenses were obtained by the LSD survey (Koopmans & Treu 2002,2003; Treu & Koopmans 2002,2003,2004; hereafter collectively KT), which published stellar velocity dispersions for 5 lenses in the redshift range z ≈ 0.5 − 1.”
• Stellar and dynamical masses of ellipticals in the Sloan Digital Sky Survey (2003, background): “Koopmans & Treu 2003) have added independent measures of the masses of the halos of ellipticals, especially at radii outside the realm of spectroscopic techniques.”
• Density profiles of galaxy groups and clusters from SDSS galaxy–galaxy weak lensing (2006, background): “Some kinematic and strong lensing studies (e.g., Rusin & Ma 2001, Koopmans & Treu 2003, Huterer & Ma 2004, Koopmans et al. 2006) have suggested a logarithmic slope ∼ −2 on scales below 10 kpc, where optical observations provide velocity dispersion information and strong lensing occurs.”