%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 }