Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Steepened inner density profiles of group galaxies via interactions: An
  N-body analysis   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.

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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: cond-mat
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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The categories of this paper are: q-fin
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom