Steepened inner density profiles of group galaxies via interactions: An N-body analysis

Abstract

We continue to see a range of values for the Hubble constant obtained from gravitationally lensed multiple image time delays when assuming an isothermal lens despite a robust value from the HST key project (72 +- 8 km s^-1 Mpc^-1. One explanation is that there is a variation in Hubble constant values due to a fundamental heterogeneity in lens galaxies present in groups. Our goal is to see if a variety of group interactions between the most massive group members can result in significant changes in the galaxy density profiles over the scale probed by strong lensing (<15 kpc). While stripping of the outer parts of the halo can be expected, the impact on inner regions where the luminous component is important is less clear in the context of lensing, though still crucial, as a steepened density profile within this inner region allows these lens systems to be consistent with current HST/WMAP estimates on H_0. We employ the particle-mesh code SUPERBOX to carry out the group interaction simulations. We simulate interactions between group members, comparing the density profile for the satellite before and after interaction for the mass range of 10^11 to 10^13 M_sun. Our investigations show a significant steepening of the density profile in the region of < 5-20 kpc, i.e. that which dominates strong lensing in lens galaxies. Additionally, the steepening in the inner region is transient in nature, with consecutive interactions returning the profile to an isothermal state within a timeframe of ~ 0.5 - 2.0 Gyr. This factor may help explain why lens galaxies that produce lower values of H_0 (i.e. those with possibly steeper profiles) are far fewer in number than those which agree with both the HST key project value for H_0 and isothermality, since one would have to observe the lens galaxy during this transient steepened phase.

arXiv comment8 pages, 6 figures, MNRAS accepted

References in corpus (34)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• The Structure of Cold Dark Matter Halos
• Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant
• Halo Models of Large Scale Structure
• The Sloan Lens ACS Survey. III - The Structure and Formation of Early-type Galaxies and their Evolution since z~1
• Dynamical family properties and dark halo scaling relations of giant elliptical galaxies
• The Structural Evolution of Substructure
• Dynamical Modeling of Velocity Profiles: The Dark Halo Around the Elliptical Galaxy NGC2434
• Density Profiles of Cold Dark Matter Substructure: Implications for the Missing Satellites Problem
• The internal structure and formation of early-type galaxies: the gravitational--lens system MG2016+112 at z=1.004
• The importance of tides for the Local Group dwarf spheroidals
• What Do Gravitational Lens Time Delays Measure?
• The internal structure of the lens PG1115+080: breaking degeneracies in the value of the Hubble Constant
• Evidence in Virgo for the Universal Dark Matter Halo
• The Time Delays of Gravitational Lens HE0435-1223: An Early-Type Galaxy With a Rising Rotation Curve
• Time delay for the gravitational lens system B0218+357
• Self-Similar Models for the Mass Profiles of Early-type Lens Galaxies
• Superbox - An Efficient Code for Collisionless Galactic Dynamics
• Truncation of galaxy dark matter halos in high density environments
• An Infrared Einstein Ring in the Gravitational Lens PG 1115+080
• A Spectroscopic Study of the Environments of Gravitational Lens Galaxies
• The Importance of Lens Galaxy Environments
• The Robustness of Dark Matter Density Profiles in Dissipationless Mergers
• Redshifts of the Gravitational Lenses MG0414+0534 and MG0751+2716
• The Hubble time inferred from 10 time-delay lenses
• The image separation distribution of strong lenses: Halo versus subhalo populations
• Modeling the dynamical evolution of the M87 globular cluster system
• Mass Along the Line of Sight to the Gravitational Lens B1608+656: Galaxy Groups and Implications for H_0
• Constraints on H_0 from the Central Velocity Dispersions of Lens Galaxies
• Gravitational lensing model degeneracies: Is steepness all-important?
• First Results from a Photometric Survey of Strong Gravitational Lens Environments
• The Double Quasar HE1104-1805: a case study for time delay determination with poorly sampled lightcurves
• Enhanced Mass-to-Light Ratios in UCDs through Tidal Interaction with the Centre of the Host Galaxy
• A simple analysis of halo density profiles using gravitational lensing time delays

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