scholarly journals Monte Carlo closure for moment-based transport schemes in general relativistic radiation hydrodynamic simulations

2018 ◽  
Vol 475 (3) ◽  
pp. 4186-4207 ◽  
Author(s):  
Francois Foucart
Keyword(s):  
Monte Carlo ◽  
Hydrodynamic Simulations ◽  
General Relativistic

scholarly journals Neutrino and γ-ray Emission from the Core of NGC1275 by Magnetic Reconnection: GRMHD Simulations and Radiative Transfer/Particle Calculations

2018 ◽  
Vol 14 (S342) ◽  
pp. 184-188
Author(s):  
J. C. Rodríguez-Ramírez ◽  
Elisabete M. de Gouveia Dal Pino ◽  
R. Alves Batista
Keyword(s):  
Monte Carlo ◽  
Radiative Transfer ◽  
Magnetic Reconnection ◽  
Neutrino Flux ◽  
Cosmic Ray ◽  
High Energy ◽  
Emission Model ◽  
The Core ◽  
Very High Energy ◽  
General Relativistic

AbstractVery high energy (VHE) emission has been detected from the radio galaxy NGC1275, establishing it as a potential cosmic-ray (CR) accelerator and a high energy neutrino source. We here study neutrino and γ-ray emission from the core of NGC1275 simulating the interactions of CRs assumed to be accelerated by magnetic reconnection, with the accreting plasma environment. To do this, we combine (i) numerical general relativistic (GR) magneto-hydrodynamics (MHD), (ii) Monte Carlo GR leptonic radiative transfer and, (iii) Monte Carlo interaction of CRs. A leptonic emission model that reproduces the SED in the [103-1010.5] eV energy range is used as the background target for photo-pion interactions+electromagnetic cascading. CRs injected with the power-law index κ=1.3 produce an emission profile that matches the VHE tail of NGC1275. The associated neutrino flux, below the IceCube limits, peaks at ∼PeV energies. However, coming from a single source, this neutrino flux may be an over-estimation.

GRB-SN CONNECTION: CENTRAL ENGINE OF LONG GRBs AND EXPLOSIVE NUCLEOSYNTHESIS

2011 ◽  
Vol 20 (10) ◽  
pp. 1975-1978 ◽  
Author(s):  
SHIGEHIRO NAGATAKI
Keyword(s):  
Numerical Simulations ◽  
Deposition Rate ◽  
Energy Deposition ◽  
Two Dimensional ◽  
Hydrodynamic Simulations ◽  
X Ray ◽  
Central Engine ◽  
Explosive Nucleosynthesis ◽  
General Relativistic ◽  
Energy Deposition Rate

I have developed two-dimensional general relativistic magnetohydrodynamic (GRMHD) code. I have performed numerical simulations of collapsars using these codes and realistic progenitor models. In the GRMHD simulation, it is shown that a jet is launched from the center of the progenitor. We also performed two-dimensional hydrodynamic simulations in the context of collapsar model to investigate the explosive nucleosynthesis happened there. It is found that the amount of 56 Ni is very sensitive to the energy deposition rate. This result means that the amount of synthesized 56 Ni can be little even if the total explosion energy is as large as 1052 erg. Thus, some GRBs can associate with faint supernovae. Thus we consider it is quite natural to detect no underlying supernova in some X-ray afterglows.

Numerical models of VHE emission by magnetic reconnection in X-ray binaries: GRMHD simulations and Monte Carlo cosmic-ray emission

2018 ◽  
Vol 14 (S346) ◽  
pp. 388-393
Author(s):  
J. C. Rodríguez-Ramírez ◽  
E. M. de Gouveia Dal Pino ◽  
R. Alves Batista
Keyword(s):  
Monte Carlo ◽  
Magnetic Reconnection ◽  
Magnetic Energy ◽  
Numerical Models ◽  
Cosmic Ray ◽  
Black Hole Binaries ◽  
Hard State ◽  
General Relativistic ◽  
Hydrodynamical Simulations ◽  
Background Gas

AbstractGalactic microquasars have been detected at very-high-energies (VHE) (> 100 GeV) and the particle acceleration mechanisms that produce this emission are not yet well-understood. Here we investigate a hadronic emission scenario where cosmic-rays (CRs) are accelerated in magnetic reconnection events by the turbulent, advected-dominated accretion flow (ADAF) believed to be present in the hard state of black hole binaries. We present Monte Carlo simulations of CR emission plus γ-γ and inverse Compton cascades, injecting CRs with a total energy consistent with the magnetic energy of the plasma. The background gas density, magnetic, and photon fields where CRs propagate and interact are modelled with general relativistic (GR), magneto-hydrodynamical simulations together with GR radiative transfer calculations. Our approach is applied to the microquasar Cygnus X-1, where we show a model configuration consistent with the VHE upper limits provided by MAGIC collaboration.

scholarly journals Constraining the Accretion Flow in Sgr A* by General Relativistic Dynamical and Polarized Radiative Modeling

2012 ◽  
Vol 8 (S290) ◽  
pp. 309-310 ◽  
Author(s):  
Roman V. Shcherbakov ◽  
Robert F. Penna ◽  
Jonathan C. McKinney
Keyword(s):  
Flow Model ◽  
Accretion Rate ◽  
Three Dimensional ◽  
Hydrodynamic Simulations ◽  
Accretion Flow ◽  
Dynamical Flow ◽  
General Relativistic ◽  
The Mean ◽  
Sgr A ◽  
Radiative Modeling

AbstractWe briefly summarize the method of simulating Sgr A* polarized sub-mm spectra from the accretion flow and fitting the observed spectrum. The dynamical flow model is based on three-dimensional general relativistic magneto hydrodynamic simulations. Fully self-consistent radiative transfer of polarized cyclo-synchrotron emission is performed. We compile a mean sub-mm spectrum of Sgr A* and fit it with the mean simulated spectra. We estimate the ranges of inclination angle θ=42°–75°, mass accretion rate Ṁ=(1.4-7.0)×10−8M⊙year−1, and electron temperature Te=(3–4)×1010K at 6M. We discuss multiple caveats in dynamical modeling, which must be resolved to make further progress.

scholarly journals Can jets make the radioactively powered emission from neutron star mergers bluer?

2020 ◽  
Vol 500 (2) ◽  
pp. 1772-1783
Author(s):  
L Nativi ◽  
M Bulla ◽  
S Rosswog ◽  
C Lundman ◽  
G Kowal ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Neutron Star ◽  
Radiative Transfer ◽  
Initial Conditions ◽  
Heavy Elements ◽  
Electromagnetic Transients ◽  
Relativistic Hydrodynamic ◽  
Hydrodynamic Simulations ◽  
Relativistic Jet ◽  
Nuclear Composition

ABSTRACT Neutron star mergers eject neutron-rich matter in which heavy elements are synthesized. The decay of these freshly synthesized elements powers electromagnetic transients (‘macronovae’ or ‘kilonovae’) whose luminosity and colour strongly depend on their nuclear composition. If the ejecta are very neutron-rich (electron fraction Ye < 0.25), they contain fair amounts of lanthanides and actinides that have large opacities and therefore efficiently trap the radiation inside the ejecta so that the emission peaks in the red part of the spectrum. Even small amounts of this high-opacity material can obscure emission from lower lying material and therefore act as a ‘lanthanide curtain’. Here, we investigate how a relativistic jet that punches through the ejecta can potentially push away a significant fraction of the high opacity material before the macronova begins to shine. We use the results of detailed neutrino-driven wind studies as initial conditions and explore with 3D special relativistic hydrodynamic simulations how jets are propagating through these winds. Subsequently, we perform Monte Carlo radiative transfer calculations to explore the resulting macronova emission. We find that the hole punched by the jet makes the macronova brighter and bluer for on-axis observers during the first few days of emission, and that more powerful jets have larger impacts on the macronova.

scholarly journals General relativistic magnetohydrodynamic and Monte Carlo Modeling of sagittarius A*

2010 ◽  
Vol 336 (1) ◽  
pp. 145-149
Author(s):  
Guy Hilburn ◽  
Edison Liang ◽  
Siming Liu ◽  
Hui Li
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Modeling ◽  
Sagittarius A ◽  
General Relativistic
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