NUMERICAL MODELING OF MULTI-WAVELENGTH SPECTRA OF M87 CORE EMISSION

作者：Hilburn G^*; Liang E P

来源：Astrophysical Journal, 2012, 746(1): 87.

DOI：10.1088/0004-637X/746/1/87

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Spectral fits to M87 core data from radio to hard X-ray are generated via a specially selected software suite, comprised of the High-Accuracy Relativistic Magnetohydrodynamics GRMHD accretion disk model and a two-dimensional Monte Carlo radiation transport code. By determining appropriate parameter changes necessary to fit X-ray-quiescent and flaring behavior of M87%26apos;s core, we assess the reasonableness of various flaring mechanisms. This shows that an accretion disk model of M87%26apos;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 %26gt; 0.8 and maximum accretion flow density n %26lt;= 3 x 10(7) cm(-3), equivalent to horizon accretion rates between (m) over dot = (M) over dot/(M) over dot(Edd) approximate to 2 x 10(-6) and 1 x 10(-5) (with (M) over dot(Edd) defined assuming a radiative efficiency n = 0.1). These results demonstrate that the immediate surroundings of M87%26apos;s core are appropriate to explain observed X-ray variability.

• 出版日期2012-2-10