Using flow models based on axisymmetric general relativistic magnetohydrodynamics simulations, we construct radiative for Sgr A*. Spectral energy distributions (SEDs) that include the effects of thermal synchrotron emission and absorption, Compton scattering, are calculated using a Monte Carlo technique. Images ray-tracing scheme. All scaled so 230 GHz flux density is 3.4 Jy. The key model parameters dimensionless black hole spin a*, inclination i, ion-to-electron temperature ratio Ti/Te. We...

We have conducted nineteen state-of-the-art 3D core-collapse supernova simulations spanning a broad range of progenitor masses. This is the largest collection sophisticated ever performed. found that while majority these models explode, not all do, and even in middle available mass may be less explodable. does mean those for which we did witness explosion would explode Nature, but they are prone to than others. One consequence "compactness" measure metric explodability. find lower-mass...

The 2017 detection of the inspiral and merger two neutron stars in gravitational waves gamma rays was accompanied by a quickly-reddening transient. Such transient predicted to occur following rapid capture (r-process) nucleosynthesis event, which synthesizes neutron-rich, radioactive nuclei can take place both dynamical ejecta wind driven off accretion torus formed after star merger. We present first three-dimensional general relativistic, full transport neutrino radiation...

Abstract This paper describes the design and implementation of our new multigroup, multidimensional radiation hydrodynamics code F ornax provides a suite tests to validate its application in wide range physical regimes. Instead focusing exclusively on neutrino relevant core-collapse supernova problem for which is primarily intended, we present here classical rigorous demonstrations performance broad hydrodynamic multigroup problems. Our solves comoving-frame moment equations using M 1...

In this paper, we present the results of our three-dimensional, multi-group, multi-neutrino-species radiation/hydrodynamic simulation using state-of-the-art code F{\sc{ornax}} terminal dynamics core a non-rotating 16-M$_{\odot}$ stellar progenitor. The calculation incorporates redistribution by inelastic scattering, correction for effect many-body interactions on neutrino-nucleon scattering rates, approximate general relativity (including effects gravitational redshifts), velocity-dependent...

Multi-dimensional instabilities have become an important ingredient in core-collapse supernova (CCSN) theory. Therefore, it is necessary to understand the driving mechanism of dominant instability. We compare our parameterized three-dimensional CCSN simulations with other buoyancy-driven and propose scaling relations for neutrino-driven convection. Through these comparisons, we infer that convection dominates post-shock turbulence simulations. In support this inference, present four major...

We present new two-dimensional (2D) axisymmetric neutrino radiation/hydrodynamic models of core-collapse supernova (CCSN) cores. use the CASTRO code, which incorporates truly multi-dimensional, multi-group, flux-limited diffusion (MGFLD) transport, including all relevant $\mathcal{O}(v/c)$ terms. Our main motivation for carrying out this study is to compare with recent 2D produced by other groups who have obtained explosions some progenitor stars and VULCAN results that did not incorporate...

A major goal over the last decade has been understanding which multidimensional effects are crucial in facilitating core-collapse supernova (CCSN) explosions. Unfortunately, much of this work necessarily assumed axisymmetry. In work, we present analyses simplified two-dimensional (2D) and three-dimensional (3D) CCSN models with comparing hydrodynamics setups that differ only dimension. Not surprisingly, find many differences between 2D 3D models. While some subtle perhaps not crucial, others...

The Event Horizon Telescope (EHT) has released analyses of reconstructed images horizon-scale millimeter emission near the supermassive black hole at center M87 galaxy. Parts made use a large library synthetic and spectra, which were produced using numerical general relativistic magnetohydrodynamics fluid simulations polarized ray tracing. In this article, we describe PATOKA pipeline, was used to generate Illinois contribution EHT simulation library. We begin by describing relevant accretion...

We describe a Monte Carlo radiative transport code intended for calculating spectra of hot, optically thin plasmas in full general relativity. The version we here is designed to model hot accretion flows the Kerr metric and therefore incorporates synchrotron emission absorption, Compton scattering. can be readily generalized, however, account other processes an arbitrary spacetime. suite test problems, demonstrate expected $N^{-1/2}$ convergence rate, where $N$ number samples. Finally...

Monte Carlo approaches to radiation transport have several attractive properties such as simplicity of implementation, high accuracy, and good parallel scaling. Moreover, methods can handle complicated geometries are relatively easy extend multiple spatial dimensions, which makes them potentially interesting in modeling complex multi-dimensional astrophysical phenomena core-collapse supernovae. The aim this paper is explore for neutrino We generalize the Implicit photon scheme Fleck &...

We investigate the structure of stalled supernova shock in both 2D and 3D explore differences effects neutrino heating standing accretion instability (SASI). find that early on amplitude dipolar mode is factors 2 to 3 smaller than 2D. However, later monopole dipole modes start grow until explosion. Whereas (l,m) = (1,0) changes sign quasi-periodically, producing "up-and-down" motion always seen modern simulations, this almost never happens. Rather, when starts grow, it grows magnitude...

We explore with self-consistent 2D F{\sc{ornax}} simulations the dependence of outcome collapse on many-body corrections to neutrino-nucleon cross sections, nucleon-nucleon bremsstrahlung rate, electron capture heavy nuclei, pre-collapse seed perturbations, and inelastic neutrino-electron scattering. Importantly, proximity criticality amplifies role even small changes in neutrino-matter couplings, such can together add produce outsized effects. When close critical condition cumulative result...

We present results of 2D axisymmetric core-collapse supernova simulations, employing the FORNAX code, nine progenitor models spanning 12 to 25 M$_{\odot}$ and evolved over a 20,000-km grid. find that four explode with inelastic scattering off electrons neutrons as well many-body correction neutrino-nucleon opacities. show these feature sharp Si-O interfaces in their density profiles, corresponding dip reduces accretion rate around stalled shock prompts explosion. The non-exploding lack such...

We present bhlight, a numerical scheme for solving the equations of general relativistic radiation magnetohydrodynamics using direct Monte Carlo solution frequency-dependent radiative transport equation. bhlight is designed to evolve black hole accretion flows at intermediate rate, in regime between classical radiatively efficient disk and inefficient flow (RIAF), which global effects play sub-dominant but non-negligible role dynamics. describe governing equations, method, idiosyncrasies our...

The mechanism driving core-collapse supernovae is sensitive to the interplay between matter and neutrino radiation. However, radiation transport very difficult simulate, several methods of varying levels approximation are available. We carefully compare for first time in multiple spatial dimensions discrete ordinates (DO) code Nagakura, Yamada, Sumiyoshi Monte Carlo (MC) Sedonu, under assumptions a static fluid background, flat spacetime, elastic scattering, full special relativity. find...

Abstract We present axisymmetric numerical simulations of radiatively inefficient accretion flows onto black holes combining general relativity, magnetohydrodynamics, self-consistent electron thermodynamics, and frequency-dependent radiation transport. investigate a range rates up to hole with spin . report on averaged flow thermodynamics as function rate. the spectra outgoing find that it varies strongly rate, from synchrotron-dominated in radio at low inverse-Compton-dominated our highest...

We model a compact black hole-accretion disk system in the collapsar scenario with full transport, frequency dependent, general relativistic radiation magnetohydrodynamics. examine whether or not winds from can undergo rapid neutron capture (r-process) nucleosynthesis and significantly contribute to solar r-process abundances. find inclusion of accurate transport has significant effects on outflows, raising electron fraction above $Y_{\rm e} \sim 0.3$ preventing third peak material being...

Abstract We present new 1D (spherical) and 2D (axisymmetric) simulations of electron-capture (EC) low-mass iron-core-collapse supernovae (SN). consider six progenitor models: the ECSN from Nomoto; two ECSN-like low-metallicity iron-core progenitors A. Heger (2016, private communication); 9, 10, 11 <?CDATA ${M}_{\odot }$?> (zero-age main-sequence) Sukhbold et al. confirm that ESCN-like explode easily even in with explosion energies up to a 0.15 Bethes ( $1\ {\rm{B}}\equiv {10}^{51}\...

Global, general relativistic magnetohydrodynamic (GRMHD) simulations of nonradiative, magnetized disks are widely used to model accreting black holes. We have performed a convergence study GRMHD models computed with HARM3D. The span factor 4 in linear resolution, from 96x96x64 384x384x256. consider three diagnostics convergence: (1) dimensionless shell-averaged quantities such as plasma \beta; (2) the azimuthal correlation length fluid variables; and (3) synthetic spectra source including...

ABSTRACT We perform the first self-consistent, time-dependent, multi-group calculations in two dimensions (2D) to address consequences of using ray-by-ray+ transport simplification core-collapse supernova simulations. Such a dimensional reduction is employed by many researchers facilitate their resource-intensive calculations. Our new code (F ornax ) implements multi-D transport, and can, zeroing out transverse flux terms, emulate scheme. Using same microphysics, initial models, resolution,...

Iharm3D is an open-source C code for simulating black hole accretion systems in arbitrary stationary spacetimes using ideal general-relativistic magnetohydrodynamics (GRMHD). It implementation of the HARM ("High Accuracy Relativistic Magnetohydrodynamics") algorithm outlined Gammie et al. (2003) with updates as McKinney & (2004) and Noble (2006). The most directly derived from Ryan (2015) but radiative transfer portions removed. a conservative finite-volume scheme solving equations GRMHD,...

In accretion-based models for Sgr A* the X-ray, infrared, and millimeter emission arise in a hot, geometrically thick accretion flow close to black hole. The spectrum size of source depend on hole mass rate $\dot{M}$. Since Gillessen et al. have recently discovered cloud moving toward that will arrive summer 2013, $\dot{M}$ may increase from its present value $\dot{M}_0$. We therefore reconsider "best-bet" model Moscibrodzka al., which is based general relativistic MHD fully radiative...

We report transient quasi-periodic oscillations (QPOs) on minute timescales in relativistic, radiative models of the galactic center source Sgr A*. The QPOs result from nonaxisymmetric $m=1$ structure accretion flow excited by MHD turbulence. Near-infrared (NIR) and X-ray power spectra show significant peaks at frequencies comparable to orbital frequency innermost stable circular orbit (ISCO) $f_o$. excess is associated with inward propagating magnetic filaments inside ISCO. amplitudes are...

Electron–positron pairs may be produced near accreting black holes by a variety of physical processes, and the resulting pair plasma accelerated collimated into relativistic jet. Here, we use self-consistent dynamical radiative model to investigate production γγ collisions in weakly accretion flows around hole mass M rate . Our flow is drawn from general magnetohydrodynamic simulations, our radiation field computed Monte Carlo transport scheme assuming electron distribution function thermal....