Photoionization Models for High Density Gas. (arXiv:2011.10603v2 [astro-ph.HE] UPDATED)

Photoionization Models for High Density Gas. (arXiv:2011.10603v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Kallman_T/0/1/0/all/0/1">T. Kallman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bautista_M/0/1/0/all/0/1">M. Bautista</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deprince_J/0/1/0/all/0/1">J. Deprince</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garcia_J/0/1/0/all/0/1">J. A. Garcia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mendoza_C/0/1/0/all/0/1">C. Mendoza</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ogorzalek_A/0/1/0/all/0/1">A. Ogorzalek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Palmeri_P/0/1/0/all/0/1">P. Palmeri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Quinet_P/0/1/0/all/0/1">P. Quinet</a>

Relativistically broadened and redshifted 6.4 — 6.9 keV iron K lines are
observed from many accretion powered objects, including X-ray binaries and
active galactic nuclei (AGN). Existence of gas close to the central engine
implies large radiation intensities and correspondingly large gas densities if
the gas is to remain partially ionized. Simple estimates indicate that high gas
densities are needed to allow survival of iron against ionization. These are
high enough that rates for many atomic processes are affected by mechanisms
related to interactions with nearby ions and electrons. Radiation intensities
are high enough that stimulated processes can be important. Most models
currently in use for interpreting relativistic lines use atomic rate
coefficients designed for use at low densities and neglect stimulated
processes. In our work so far we have presented atomic structure calculations
with the goal of providing physically appropriate models at densities
consistent with line-emitting gas near compact objects. In this paper we apply
these rates to photoionization calculations, and produce ionization balance
curves and X-ray emissivities and opacities which are appropriate for high
densities and high radiation intensities. The final step in our program will be
presented in a subsequent paper: Model atmosphere calculations which
incorporate these rates into synthetic spectra.

Relativistically broadened and redshifted 6.4 — 6.9 keV iron K lines are
observed from many accretion powered objects, including X-ray binaries and
active galactic nuclei (AGN). Existence of gas close to the central engine
implies large radiation intensities and correspondingly large gas densities if
the gas is to remain partially ionized. Simple estimates indicate that high gas
densities are needed to allow survival of iron against ionization. These are
high enough that rates for many atomic processes are affected by mechanisms
related to interactions with nearby ions and electrons. Radiation intensities
are high enough that stimulated processes can be important. Most models
currently in use for interpreting relativistic lines use atomic rate
coefficients designed for use at low densities and neglect stimulated
processes. In our work so far we have presented atomic structure calculations
with the goal of providing physically appropriate models at densities
consistent with line-emitting gas near compact objects. In this paper we apply
these rates to photoionization calculations, and produce ionization balance
curves and X-ray emissivities and opacities which are appropriate for high
densities and high radiation intensities. The final step in our program will be
presented in a subsequent paper: Model atmosphere calculations which
incorporate these rates into synthetic spectra.

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