Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Implications of Quasar Black Hole Masses at High Redshifts   We investigated a sample of 15 luminous high-redshift quasars (3.3 < z < 5.1)
to measure the mass of their super-massive black holes (SMBH) and compare, for
the first time, results based on CIV, MgII, and Hbeta emission lines at
high-redshifts. Assuming gravitationally bound orbits as dominant broad-line
region gas motion, we determine black hole masses in the range of M_bh = 2
times 10^8 M_sun up to M_bh = 4 times 10^10 M_sun. While the black hole mass
estimates based on CIV and Hbeta agree well, MgII typically indicates a factor
of $\sim 5 \times$ lower SMBH masses. A flatter slope of the Hbeta radius -
luminosity relation, a possibly steeper slope of the MgII radius - luminosity
relation, and a slightly larger radius of the MgII BLR than for Hbeta could
relax the discrepancy. In spite of these uncertainties, the CIV, MgII, and
Hbeta emission lines consistently indicate super-massive black hole masses of
several times 10^9 M_sun at redshifts up to z = 5.1. Assuming logarithmic
growth by spherical accretion with a mass to energy conversion efficiency of
epsilon = 0.1 and an Eddington ratio L_bol / L_edd calculated for each quasar
individually, we estimate black hole growth-times of the order of several ~100
Myr which are smaller than the age of the universe at the corresponding
redshift. Assuming high-mass seed black holes (M_bh^seed = 10^3 to 10^5 M_sun)
the SMBHs in the z = 3.5 quasars began to grow at redshifts z > 4, while for
the quasars with z > 4.5 they started at z = 6 to 10. These estimated time
scales for forming SMBHs at high redshifts, together with previous studies
indicating high quasar metallicities, suggest that the main SMBH growth phase
occurs roughly contemporaneously with a period of violent and extensive star
formation in proto-galactic nuclei.

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The categories of this paper are: q-alg
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
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The categories of this paper are: nlin
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The categories of this paper are: alg-geom