Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Properties of High Redshift Quasars-I: Evolution of the super-massive
  black-hole to halo mass ratio   In the local universe, the masses of Super-Massive Black-Holes (SMBH) appear
to correlate with physical properties of their hosts, including the mass of the
dark-matter halos. At higher redshifts, we observe the growth of SMBHs
indirectly through identification of high redshift quasars. However information
on their hosts is difficult to obtain. In this paper we determine the masses of
halos that host high redshift quasars (at z>4) by comparing the rate of growth
of quasar density with that predicted by the Press-Schechter mass function. The
host mass determined depends on how the ratio between SMBH and host halo mass
evolves with redshift. Assuming the ratio between SMBH and halo mass does not
evolve with redshift, we find a host halo mass of log(M)=11.7+/-0.3 solar
masses. Even if the quasars shine at their Eddington limit, this mass is
significantly smaller than that seen in the local universe. Indeed the
null-hypothesis, of a constant SMBH to halo mass ratio at all redshifts, can be
ruled out at greater than a 5-sigma level. SMBHs must therefore have
contributed a larger fraction to the host mass in the past. Including redshift
evolution of the SMBH to halo mass ratio, we find larger halo masses of
log(M)=12.4+/-0.3 solar masses, and a ratio between SMBH and halo mass that
increases with redshift as ~(1+z)^1.5 are required to be consistent with both
local and high redshift observations. We investigate restrictions placed on the
critical linear overdensity of quasar hosts at their epoch of virialisation and
find that it cannot exceed the traditional value of delta_c=1.69 by more than a
factor of two. Finally, we find that the high redshift quasars are hosted by
fluctuations on scales that have a variance of (delta M/M) = 2-3, corresponding
to (3-4.5)-sigma fluctuations in the density field.

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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol