  We describe results from a new technique for the prediction of complete,
self-consistent X-ray spectra from three-dimensional General Relativistic
magnetohydrodynamic (GRMHD) simulations of black hole accretion flows. Density
and cooling rate data from a HARM3D GRMHD simulation are processed by both an
improved version of the Monte Carlo radiation transport code PANDURATA (in the
corona) and the Feautrier solver PTRANSX (in the disk), with XSTAR subroutines.
The codes are run in a sequential but iterative fashion to achieve globally
energy-conserving and self-consistent radiation fields, temperature maps, and
photoionization equilibria. The output is the X-ray spectrum as seen by a
distant observer. For the example cases we consider here---a non-rotating $10
M_\odot$ black hole with solar abundances, accreting at 0.01, 0.03, 0.1, or 0.3
Eddington---we find spectra resembling actual observations of stellar-mass
black holes in the soft or steep power-law state: broad thermal peaks (at 1-3
keV), steep power-laws extending to high energy ($\Gamma$ = 2.7-4.5), and
prominent, asymmetric Fe K$\alpha$ emission lines with equivalent widths in the
range 40-400 eV (larger EW at lower accretion rates). By starting with
simulation data, we obviate the need for parameterized descriptions of the
accretion flow geometry---no a priori specification of the corona's shape or
flux, or the disk temperature or density, etc., are needed. Instead, we apply
the relevant physical principles to simulation output using appropriate
numerical techniques; this procedure allows us to calculate
inclination-dependent spectra after choosing only a small number of physically
meaningful parameters: black hole mass and spin, accretion rate, and elemental
abundances.
