Guy Hilburn, Edison Liang
Spectral fits to M87 core data from radio to hard x-ray are generated via a
specially selected software suite, comprised of the HARM GRMHD accretion disk
model and a 2D Monte Carlo radiation transport code. By determining appropriate
parameter changes necessary to fit x-ray quiescent and flaring behavior of
M87's core, we assess the reasonableness of various flaring mechanisms. This
shows that an accretion disk model of M87's core out to 28 GM/c^2 can describe
the inner emissions. High spin rates show GRMHD-driven polar outflow
generation, without citing an external jet model. Our results favor accretion
rate changes as the dominant mechanism of x-ray flux and index changes, with
variations in density of approximately 20% necessary to scale between the
average x-ray spectrum and flaring or quiescent spectra. The best fit
parameters are black hole spin a/M > 0.8 and maximum accretion flow density n
<= 3x10^7 cm^-3, equivalent to horizon accretion rates between m_dot =
M_dot/M_dot_Edd ~ 2x10^-6 and 1x10^-5 (with M_dot_Edd defined assuming a
radiative efficiency eta = 0.1). These results demonstrate that the immediate
surroundings of M87's core are appropriate to explain observed x-ray
variability.
View original:
http://arxiv.org/abs/1109.2847
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