We investigate whether the hard X-ray photon index ($\Gamma$) versus
accretion rate correlation for super-Eddington accreting quasars is different
from that for sub-Eddington accreting quasars. We construct a sample of 113
bright quasars from the Sloan Digital Sky Survey Data Release 14 quasar
catalog, including 38 quasars as the super-Eddington subsample and 75 quasars
as the sub-Eddington subsample. We derive black-hole masses using a
simple-epoch virial mass formula based on the $H\beta$ lines, and we use
the standard thin disk model to derive the dimensionless accretion rates
($\mathscrM$) for our sample. The X-ray data for these quasars are
collected from the Chandra and XMM-Newton archives. We fit the hard X-ray
spectra using a single power-law model to obtain $\Gamma$ values. We find a
statistically significant ($R_S=0.43$, $p=7.7510^-3$)
correlation between $\Gamma$ and $\mathscrM$ for the super-Eddington
subsample. The $\Gamma$-$\mathscrM$ correlation for the sub-Eddington
subsample is also significant, but weaker ($R_S=0.30$,
$p=9.9810^-3$). Linear regression analysis shows that $\rm
\Gamma=(0.34\pm0.11)log\mathscrM+(1.71\pm0.17)$ and $\rm
\Gamma=(0.09\pm0.04)log\mathscrM+(1.93\pm0.04)$ for the super-
and sub-Eddington subsamples, respectively. The $\Gamma$-$\mathscrM$
correlations of the two subsamples are different, suggesting different
disk-corona connections in these two types of systems. We propose one
qualitative explanation of the steeper $\Gamma$-$\mathscrM$
correlation in the super-Eddington regime that involves larger seed photon
fluxes received by the compact coronae from the thick disks in super-Eddington
accreting quasars.
Description
On the relation between hard X-ray photon index versus Accretion Rate for super-Eddington accreting quasars
%0 Journal Article
%1 huang2020relation
%A Huang, Jian
%A Luo, Bin
%A Hu, Chen
%A Du, Pu
%A Wang, Jian-Min
%A Li, Yi-Jia
%D 2020
%K AGN X-ray superEddington
%T On the relation between hard X-ray photon index versus Accretion Rate
for super-Eddington accreting quasars
%U http://arxiv.org/abs/2005.01749
%X We investigate whether the hard X-ray photon index ($\Gamma$) versus
accretion rate correlation for super-Eddington accreting quasars is different
from that for sub-Eddington accreting quasars. We construct a sample of 113
bright quasars from the Sloan Digital Sky Survey Data Release 14 quasar
catalog, including 38 quasars as the super-Eddington subsample and 75 quasars
as the sub-Eddington subsample. We derive black-hole masses using a
simple-epoch virial mass formula based on the $H\beta$ lines, and we use
the standard thin disk model to derive the dimensionless accretion rates
($\mathscrM$) for our sample. The X-ray data for these quasars are
collected from the Chandra and XMM-Newton archives. We fit the hard X-ray
spectra using a single power-law model to obtain $\Gamma$ values. We find a
statistically significant ($R_S=0.43$, $p=7.7510^-3$)
correlation between $\Gamma$ and $\mathscrM$ for the super-Eddington
subsample. The $\Gamma$-$\mathscrM$ correlation for the sub-Eddington
subsample is also significant, but weaker ($R_S=0.30$,
$p=9.9810^-3$). Linear regression analysis shows that $\rm
\Gamma=(0.34\pm0.11)log\mathscrM+(1.71\pm0.17)$ and $\rm
\Gamma=(0.09\pm0.04)log\mathscrM+(1.93\pm0.04)$ for the super-
and sub-Eddington subsamples, respectively. The $\Gamma$-$\mathscrM$
correlations of the two subsamples are different, suggesting different
disk-corona connections in these two types of systems. We propose one
qualitative explanation of the steeper $\Gamma$-$\mathscrM$
correlation in the super-Eddington regime that involves larger seed photon
fluxes received by the compact coronae from the thick disks in super-Eddington
accreting quasars.
@article{huang2020relation,
abstract = {We investigate whether the hard X-ray photon index (${\Gamma}$) versus
accretion rate correlation for super-Eddington accreting quasars is different
from that for sub-Eddington accreting quasars. We construct a sample of 113
bright quasars from the Sloan Digital Sky Survey Data Release 14 quasar
catalog, including 38 quasars as the super-Eddington subsample and 75 quasars
as the sub-Eddington subsample. We derive black-hole masses using a
simple-epoch virial mass formula based on the ${\rm H\beta}$ lines, and we use
the standard thin disk model to derive the dimensionless accretion rates
($\dot{\mathscr{M}}$) for our sample. The X-ray data for these quasars are
collected from the Chandra and XMM-Newton archives. We fit the hard X-ray
spectra using a single power-law model to obtain ${\Gamma}$ values. We find a
statistically significant ($R_{\rm S}=0.43$, $p=7.75\times{10}^{-3}$)
correlation between ${\Gamma}$ and $\dot{\mathscr{M}}$ for the super-Eddington
subsample. The ${\Gamma}$-$\dot{\mathscr{M}}$ correlation for the sub-Eddington
subsample is also significant, but weaker ($R_{\rm S}=0.30$,
$p=9.98\times{10}^{-3}$). Linear regression analysis shows that ${\rm
\Gamma}=(0.34\pm0.11){\rm log}{\dot{\mathscr{M}}}+(1.71\pm0.17)$ and ${\rm
\Gamma}=(0.09\pm0.04){\rm log}{\dot{\mathscr{M}}}+(1.93\pm0.04)$ for the super-
and sub-Eddington subsamples, respectively. The ${\Gamma}$-$\dot{\mathscr{M}}$
correlations of the two subsamples are different, suggesting different
disk-corona connections in these two types of systems. We propose one
qualitative explanation of the steeper ${\Gamma}$-$\dot{\mathscr{M}}$
correlation in the super-Eddington regime that involves larger seed photon
fluxes received by the compact coronae from the thick disks in super-Eddington
accreting quasars.},
added-at = {2020-05-06T09:27:26.000+0200},
author = {Huang, Jian and Luo, Bin and Hu, Chen and Du, Pu and Wang, Jian-Min and Li, Yi-Jia},
biburl = {https://www.bibsonomy.org/bibtex/2ed33703bda402dad66b91c080f660a32/kiwasawa},
description = {On the relation between hard X-ray photon index versus Accretion Rate for super-Eddington accreting quasars},
interhash = {b59e3e1cb0f629639d82533d7ecda6a2},
intrahash = {ed33703bda402dad66b91c080f660a32},
keywords = {AGN X-ray superEddington},
note = {cite arxiv:2005.01749Comment: 14 pages, 10 figures, accepted for publication in ApJ},
timestamp = {2020-05-06T09:27:26.000+0200},
title = {On the relation between hard X-ray photon index versus Accretion Rate
for super-Eddington accreting quasars},
url = {http://arxiv.org/abs/2005.01749},
year = 2020
}