Does the mid-infrared-hard X-ray luminosity relation for active galactic nuclei depend on Eddington ratio?. (arXiv:1812.09485v1 [astro-ph.GA])

Does the mid-infrared-hard X-ray luminosity relation for active galactic nuclei depend on Eddington ratio?. (arXiv:1812.09485v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Toba_Y/0/1/0/all/0/1">Yoshiki Toba</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ueda_Y/0/1/0/all/0/1">Yoshihiro Ueda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsuoka_K/0/1/0/all/0/1">Kenta Matsuoka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shidatsu_M/0/1/0/all/0/1">Megumi Shidatsu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nagao_T/0/1/0/all/0/1">Tohru Nagao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Terashima_Y/0/1/0/all/0/1">Yuichi Terashima</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_W/0/1/0/all/0/1">Wei-Hao Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chang_Y/0/1/0/all/0/1">Yu-Yen Chang</a>

We revisit the correlation between the mid-infrared (6 $mu$m) and hard X-ray
(2–10 keV) luminosities of active galactic nuclei (AGNs) to understand the
physics behind it. We construct an X-ray flux-limited sample of 571 type 1 AGNs
with $f_{0.5-2.0 ,{rm keV}} > 2.4 times 10^{-12}$ erg cm$^{-2}$ s$^{-1}$,
drawn from the ROSAT Bright Survey catalog. Cross-matching the sample with
infrared data taken from Wide-field Infrared Survey Explorer, we investigate
the relation between the rest-frame 6 $mu$m luminosity ($L_{rm 6}$) and the
rest-frame 2–10 keV luminosity ($L_{rm X}$), where $L_{rm 6}$ is corrected
for the contamination of host galaxies by using the spectral energy
distribution fitting technique. We confirm that $L_{rm 6}$ and $L_{rm X}$ are
correlated over four orders of magnitude, in the range of $L_{rm X} =
10^{42-46}$ erg s$^{-1}$. We investigate what kinds of physical parameters
regulate this correlation. We find that $L_{rm X}$/$L_{rm 6}$ clearly depends
on the Eddington ratio ($lambda_{rm Edd}$) as $log lambda_{rm Edd} =
-(0.56 pm 0.10) log , (L_{rm X}/L_{rm 6}) – (1.07 pm 0.05)$, even taking
into account quasars that are undetected by ROSAT as well as those detected by
XMM-Newton in the literature. We also add hyper-luminous quasars with $L_{rm
6}$ $>$ 10$^{46}$ erg s$^{-1}$ in the literature and perform a correlation
analysis. The resultant correlation coefficient is $-0.41 pm 0.07$, indicating
a moderately tight correlation between $L_{rm X}$/$L_{rm 6}$ and
$lambda_{rm Edd}$. This means that AGNs with high Eddington ratios tend to
have lower X-ray luminosities with respect to the mid-infrared luminosities.
This dependence can be interpreted as a change in the structure of the
accretion flow.

We revisit the correlation between the mid-infrared (6 $mu$m) and hard X-ray
(2–10 keV) luminosities of active galactic nuclei (AGNs) to understand the
physics behind it. We construct an X-ray flux-limited sample of 571 type 1 AGNs
with $f_{0.5-2.0 ,{rm keV}} > 2.4 times 10^{-12}$ erg cm$^{-2}$ s$^{-1}$,
drawn from the ROSAT Bright Survey catalog. Cross-matching the sample with
infrared data taken from Wide-field Infrared Survey Explorer, we investigate
the relation between the rest-frame 6 $mu$m luminosity ($L_{rm 6}$) and the
rest-frame 2–10 keV luminosity ($L_{rm X}$), where $L_{rm 6}$ is corrected
for the contamination of host galaxies by using the spectral energy
distribution fitting technique. We confirm that $L_{rm 6}$ and $L_{rm X}$ are
correlated over four orders of magnitude, in the range of $L_{rm X} =
10^{42-46}$ erg s$^{-1}$. We investigate what kinds of physical parameters
regulate this correlation. We find that $L_{rm X}$/$L_{rm 6}$ clearly depends
on the Eddington ratio ($lambda_{rm Edd}$) as $log lambda_{rm Edd} =
-(0.56 pm 0.10) log , (L_{rm X}/L_{rm 6}) – (1.07 pm 0.05)$, even taking
into account quasars that are undetected by ROSAT as well as those detected by
XMM-Newton in the literature. We also add hyper-luminous quasars with $L_{rm
6}$ $>$ 10$^{46}$ erg s$^{-1}$ in the literature and perform a correlation
analysis. The resultant correlation coefficient is $-0.41 pm 0.07$, indicating
a moderately tight correlation between $L_{rm X}$/$L_{rm 6}$ and
$lambda_{rm Edd}$. This means that AGNs with high Eddington ratios tend to
have lower X-ray luminosities with respect to the mid-infrared luminosities.
This dependence can be interpreted as a change in the structure of the
accretion flow.

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