Broad Band X-ray Constraints on the Accreting Black Hole in Quasar 4C 74.26. (arXiv:1909.05861v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Tzanavaris_P/0/1/0/all/0/1">P. Tzanavaris</a> (1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Yaqoob_T/0/1/0/all/0/1">T. Yaqoob</a> (1, 2, 3), <a href="http://arxiv.org/find/astro-ph/1/au:+LaMassa_S/0/1/0/all/0/1">S. LaMassa</a> (4), <a href="http://arxiv.org/find/astro-ph/1/au:+Yukita_M/0/1/0/all/0/1">M. Yukita</a> (1, 3), <a href="http://arxiv.org/find/astro-ph/1/au:+Ptak_A/0/1/0/all/0/1">A. Ptak</a> (1, 3) ((1) NASA/GSFC, (2) CRESST/UMBC, (3) JHU, (4) STScI)
X-ray data for quasar 4C 74.26 have previously been modeled with a broad Fe
K$alpha$ emission line and reflection continuum originating in the inner part
of the accretion disk around the central supermassive black hole (SMBH), i.e.
the strong gravity regime. We modeled broadband X-ray spectra from $Suzaku$ and
$NuSTAR$ with MYTORUS, self-consistently accounting for Fe K$alpha$ line
emission, as well as direct and reflected continuum emission, from finite
column density matter. A narrow Fe K$alpha$ emission line originating in an
X-ray reprocessor with solar Fe abundance far from the central SMBH is
sufficient to produce excellent fits for all spectra. For the first time, we
are able to measure the global, out of the line-of-sight column density to be
in the range $sim$$1.5$ to $sim$$2.9times10^{24}$ cm$^{-2}$, i.e. in the
Compton thick regime, while the line-of-sight column density is Compton thin in
all observations. The Fe K$alpha$ emission line is unresolved in all but one
observations. The Compton scattered continuum from distant matter removes the
need for relativistic broadening of the Fe K$alpha$ emission line, which is
required for SMBH spin measurements. The resolved line observation can
alternatively be modeled with a relativistic model but we do not find evidence
for a truncated accretion disk model. We conclude that the X-ray emission in
these 4C 74.26 data is unlikely to originate in the inner accretion disk region
and thus cannot be used to measure SMBH spin.
X-ray data for quasar 4C 74.26 have previously been modeled with a broad Fe
K$alpha$ emission line and reflection continuum originating in the inner part
of the accretion disk around the central supermassive black hole (SMBH), i.e.
the strong gravity regime. We modeled broadband X-ray spectra from $Suzaku$ and
$NuSTAR$ with MYTORUS, self-consistently accounting for Fe K$alpha$ line
emission, as well as direct and reflected continuum emission, from finite
column density matter. A narrow Fe K$alpha$ emission line originating in an
X-ray reprocessor with solar Fe abundance far from the central SMBH is
sufficient to produce excellent fits for all spectra. For the first time, we
are able to measure the global, out of the line-of-sight column density to be
in the range $sim$$1.5$ to $sim$$2.9times10^{24}$ cm$^{-2}$, i.e. in the
Compton thick regime, while the line-of-sight column density is Compton thin in
all observations. The Fe K$alpha$ emission line is unresolved in all but one
observations. The Compton scattered continuum from distant matter removes the
need for relativistic broadening of the Fe K$alpha$ emission line, which is
required for SMBH spin measurements. The resolved line observation can
alternatively be modeled with a relativistic model but we do not find evidence
for a truncated accretion disk model. We conclude that the X-ray emission in
these 4C 74.26 data is unlikely to originate in the inner accretion disk region
and thus cannot be used to measure SMBH spin.
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