Numerical Modeling of Multi-Wavelength Spectra of M87 Core Emission

Abstract

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 twodimensional 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 3 × 10 7 cm −3 , equivalent to horizon accretion rates betweenṁ =Ṁ/Ṁ Edd ≈ 2 × 10 −6 and 1 × 10 −5 (withṀ Edd defined assuming a radiative efficiency η = 0.1). These results demonstrate that the immediate surroundings of M87's core are appropriate to explain observed X-ray variability.

General relativistic magnetohydrodynamical simulations of the jet in M 87

“…The resulting best fiṫ M will vary depending upon the underlying electron distribution functions in the accretion disk and jet. They typically vary (Mościbrodzka et al 2011, Hilburn & Liang 2012. In our fiducial model RH100, we findṀ = 9 × 10 −3 M yr −1 .…”

“…General relativistic radiative transfer (GRRT) models can predict the general relativistic magnetohydrodynamical (GRMHD) simulation spectrum and appearance. This allows us to compare dynamical models directly to VLBI observations (e.g., Dexter et al 2012;Hilburn & Liang 2012;Mościbrodzka et al 2014). …”

Probing the Central Black Hole in M87 With Gamma-Rays

“…1,58,62 If true, this would most likely argue against an ADAF (bremsstrahlung) origin of the Chandra X-ray variations. 59…”

Black hole spin from wobbling and rotation of the M87 jet and a sign of a magnetically arrested disc

“…Then, Li et al (2009) extended the previous model based on self-similar ADAF solutions in Newtonian approximation and considered GR effects for a HD radiatively inefficient accretion flow (RIAF), which gave a > 0.8. Numerically modelling spectral fits to the M87 core data from radio to hard X-ray under the condition that all the emission goes from the immediate surroundings of the central black hole, Hilburn & Liang (2012) offered the same constraint from the best-fitting parameters. At the same time, Doeleman et al (2012) carried out 1.3-mm VLBI observations of the M87 core and found a full width at half-maximum size of (5.5 ± 0.4)R Sch .…”