Revisiting the bulge-halo conspiracy II: Towards explaining its puzzling dependence on redshift

Abstract

We carry out a systematic investigation of the total mass density profile of massive (Mstar~3e11 Msun) early-type galaxies and its dependence on redshift, specifically in the range 0<z<1. We start from a large sample of SDSS early-type galaxies with stellar masses and effective radii measured assuming two different profiles, de Vaucouleurs and Sérsic. We assign dark matter haloes to galaxies via abundance matching relations with standard LCDM profiles and concentrations. We then compute the total, mass-weighted density slope at the effective radius gamma', and study its redshift dependence at fixed stellar mass. We find that a necessary condition to induce an increasingly flatter gamma' at higher redshifts, as suggested by current strong lensing data, is to allow the intrinsic stellar profile of massive galaxies to be Sérsic and the input Sérsic index n to vary with redshift approximately as n(z)~(1+z)^(-1). This conclusion holds irrespective of the input Mstar-Mhalo relation, the assumed stellar initial mass function, or even the chosen level of adiabatic contraction in the model. Secondary contributors to the observed redshift evolution of gamma' may come from an increased contribution at higher redshifts of adiabatic contraction and/or bottom-light stellar initial mass functions. The strong lensing selection effects we have simulated seem not to contribute to this effect. A steadily increasing Sérsic index with cosmic time is supported by independent observations, though it is not yet clear whether cosmological hierarchical models (e.g., mergers) are capable of reproducing such a fast and sharp evolution.

14 pages, 8 figures. MNRAS, accepted. Main result of the paper in Figure 2

References in corpus (26)

• The hierarchical formation of the brightest cluster galaxies
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• The Structure & Dynamics of Massive Early-type Galaxies: On Homology, Isothermality and Isotropy inside one Effective Radius
• A universal model for halo concentrations
• A Revised Model for the Formation of Disk Galaxies: Low Spin and Dark-Halo Expansion
• A catalogue of 2D photometric decompositions in the SDSS-DR7 spectroscopic main galaxy sample: preferred models and systematics
• Radial variations in the stellar initial mass function of early-type galaxies
• Curvature in the scaling relations of early-type galaxies
• The galaxy-halo connection from a joint lensing, clustering and abundance analysis in the CFHTLenS/VIPERS field
• The SL2S Galaxy-scale Lens Sample. V. Dark Matter Halos and Stellar IMF of Massive Early-type Galaxies out to Redshift 0.8
• The SL2S Galaxy-scale Lens Sample. II. Cosmic evolution of dark and luminous mass in early-type galaxies
• The stellar-to-halo mass relations of local galaxies segregates by color
• Small scatter and nearly-isothermal mass profiles to four half-light radii from two-dimensional stellar dynamics of early-type galaxies
• Physical properties underlying observed kinematics of satellite galaxies
• The Stellar Initial Mass Function in Early-Type Galaxies From Absorption Line Spectroscopy. IV. A Super-Salpeter IMF in the center of NGC 1407 from Non-Parametric Models
• Systematic variations of central mass density slopes in early-type galaxies
• The KMOS Cluster Survey (KCS) I: The fundamental plane and the formation ages of cluster galaxies at redshift $1.4<z<1.6$
• Evolution of central dark matter of early-type galaxies up to z ~ 0.8
• Selection bias in dynamically-measured super-massive black hole samples: dynamical masses and dependence on Sérsic index
• The stellar initial mass function at 0.9<z<1.5
• Setting firmer constraints on the evolution of the most massive, central galaxies from their local abundances and ages
• Merger-driven evolution of the effective stellar initial mass function of massive early-type galaxies
• Revised Mass-to-Light Ratios For Nearby Galaxy Groups and Clusters
• The Stellar Mass - Halo Mass Relation for Low Mass X-ray Groups at 0.5<z<1 in the CDFS with CSI

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