We present the analysis of optical and near-infrared spectra of the only four
z>6.5 quasars known to date, discovered in the UKIDSS-LAS and VISTA-VIKING
surveys. Our data-set consists of VLT/X-Shooter and Magellan/FIRE observations
of the z>6.5 quasars, and includes new deep VLT/X-Shooter observations of the
highest redshift quasar known to date (z=7.1). These are the best optical/NIR
spectroscopic data that are likely to be obtained for the z>6.5 sample using
current 6-10 m facilities. We estimate the black hole mass, the Eddington
ratio, and the SiIV/CIV, CIII/CIV, and FeII/MgII emission-line flux ratios. We
perform spectral modeling using a procedure that allows us to derive a
probability distribution for the continuum components and to obtain the quasar
properties weighted upon the underlying distribution of continuum models. The
z>6.5 quasars show the same emission properties as their counterparts at lower
redshifts. The z>6.5 quasars host black holes with masses of ~10^9 M_sun that
are accreting close to the Eddington luminosity (<log(L_Bol/L_Edd)>=
-0.4+/-0.2), in agreement with what has been observed for a sample of 4.0<z<6.5
quasars. By comparing the SiIV/CIV and CIII/CIV flux ratios with the results
obtained from luminosity-matched samples at z~6 and 2<z<4.5, we find no
evidence of evolution of the line ratios with cosmic time. We compare the
measured FeII/MgII flux ratios with those obtained for a sample of 4.0<z<6.4
sources. The two samples are analyzed using a consistent procedure. The
FeII/MgII flux ratio does not show any evolution in the 4.0<z<7.1 redshift
range. Under the assumption that the FeII/MgII traces the Fe/Mg abundance
ratio, this implies the presence of major episodes of chemical enrichment in
the quasar hosts in the first ~0.8 Gyr after the Big Bang.
Description
[1311.3260] Black hole mass estimates and emission-line properties of a sample of redshift z>6.5 quasars
%0 Generic
%1 derosa2013black
%A De Rosa, G.
%A Venemans, B. P.
%A Decarli, R.
%A Gennaro, M.
%A Simcoe, R. A.
%A Dietrich, M.
%A Peterson, B. M.
%A Walter, F.
%A Frank, S.
%A McMahon, R. G.
%A Hewett, P. C.
%A Mortlock, D. J.
%A Simpson, C.
%A Warren, S. J.
%D 2013
%K black high-z hole mass
%T Black hole mass estimates and emission-line properties of a sample of
redshift z>6.5 quasars
%U http://arxiv.org/abs/1311.3260
%X We present the analysis of optical and near-infrared spectra of the only four
z>6.5 quasars known to date, discovered in the UKIDSS-LAS and VISTA-VIKING
surveys. Our data-set consists of VLT/X-Shooter and Magellan/FIRE observations
of the z>6.5 quasars, and includes new deep VLT/X-Shooter observations of the
highest redshift quasar known to date (z=7.1). These are the best optical/NIR
spectroscopic data that are likely to be obtained for the z>6.5 sample using
current 6-10 m facilities. We estimate the black hole mass, the Eddington
ratio, and the SiIV/CIV, CIII/CIV, and FeII/MgII emission-line flux ratios. We
perform spectral modeling using a procedure that allows us to derive a
probability distribution for the continuum components and to obtain the quasar
properties weighted upon the underlying distribution of continuum models. The
z>6.5 quasars show the same emission properties as their counterparts at lower
redshifts. The z>6.5 quasars host black holes with masses of ~10^9 M_sun that
are accreting close to the Eddington luminosity (<log(L_Bol/L_Edd)>=
-0.4+/-0.2), in agreement with what has been observed for a sample of 4.0<z<6.5
quasars. By comparing the SiIV/CIV and CIII/CIV flux ratios with the results
obtained from luminosity-matched samples at z~6 and 2<z<4.5, we find no
evidence of evolution of the line ratios with cosmic time. We compare the
measured FeII/MgII flux ratios with those obtained for a sample of 4.0<z<6.4
sources. The two samples are analyzed using a consistent procedure. The
FeII/MgII flux ratio does not show any evolution in the 4.0<z<7.1 redshift
range. Under the assumption that the FeII/MgII traces the Fe/Mg abundance
ratio, this implies the presence of major episodes of chemical enrichment in
the quasar hosts in the first ~0.8 Gyr after the Big Bang.
@misc{derosa2013black,
abstract = {We present the analysis of optical and near-infrared spectra of the only four
z>6.5 quasars known to date, discovered in the UKIDSS-LAS and VISTA-VIKING
surveys. Our data-set consists of VLT/X-Shooter and Magellan/FIRE observations
of the z>6.5 quasars, and includes new deep VLT/X-Shooter observations of the
highest redshift quasar known to date (z=7.1). These are the best optical/NIR
spectroscopic data that are likely to be obtained for the z>6.5 sample using
current 6-10 m facilities. We estimate the black hole mass, the Eddington
ratio, and the SiIV/CIV, CIII]/CIV, and FeII/MgII emission-line flux ratios. We
perform spectral modeling using a procedure that allows us to derive a
probability distribution for the continuum components and to obtain the quasar
properties weighted upon the underlying distribution of continuum models. The
z>6.5 quasars show the same emission properties as their counterparts at lower
redshifts. The z>6.5 quasars host black holes with masses of ~10^9 M_sun that
are accreting close to the Eddington luminosity (<log(L_Bol/L_Edd)>=
-0.4+/-0.2), in agreement with what has been observed for a sample of 4.0<z<6.5
quasars. By comparing the SiIV/CIV and CIII]/CIV flux ratios with the results
obtained from luminosity-matched samples at z~6 and 2<z<4.5, we find no
evidence of evolution of the line ratios with cosmic time. We compare the
measured FeII/MgII flux ratios with those obtained for a sample of 4.0<z<6.4
sources. The two samples are analyzed using a consistent procedure. The
FeII/MgII flux ratio does not show any evolution in the 4.0<z<7.1 redshift
range. Under the assumption that the FeII/MgII traces the Fe/Mg abundance
ratio, this implies the presence of major episodes of chemical enrichment in
the quasar hosts in the first ~0.8 Gyr after the Big Bang.},
added-at = {2013-11-14T16:29:52.000+0100},
author = {De Rosa, G. and Venemans, B. P. and Decarli, R. and Gennaro, M. and Simcoe, R. A. and Dietrich, M. and Peterson, B. M. and Walter, F. and Frank, S. and McMahon, R. G. and Hewett, P. C. and Mortlock, D. J. and Simpson, C. and Warren, S. J.},
biburl = {https://www.bibsonomy.org/bibtex/2b2f5f3e2cc90fcabed02988a1668ba68/miki},
description = {[1311.3260] Black hole mass estimates and emission-line properties of a sample of redshift z>6.5 quasars},
interhash = {6bfd548dcc111b4b958c16a551100635},
intrahash = {b2f5f3e2cc90fcabed02988a1668ba68},
keywords = {black high-z hole mass},
note = {cite arxiv:1311.3260Comment: 21 pages, 11 figures. Submitted to ApJ},
timestamp = {2013-11-14T16:29:52.000+0100},
title = {Black hole mass estimates and emission-line properties of a sample of
redshift z>6.5 quasars},
url = {http://arxiv.org/abs/1311.3260},
year = 2013
}