Paper: astro-ph/0506368
Date: Thu, 16 Jun 2005 06:16:33 GMT (406kb)

Title: Jet Formation in Black Hole Accretion Systems I: Theoretical Unification
Model

Authors: Jonathan C. McKinney
Comments: 24 pages, 4 figures, submitted to ApJ
\\
Two types of relativistic jets are suggested to form near accreting black
holes: a potentially ultrarelativistic Poynting-dominated jet and a
Poynting-baryon jet. One source of jet matter is electron-positron pair
production, which is driven by neutrino annihilation in GRBs and photon
annihilation in AGN and x-ray binaries. GRB Poynting-dominated jets are also
loaded by electron-proton pairs by the collisional cascade of Fick-diffused
free neutrons. We show that, for the collapsar model, the neutrino-driven
enthalpy flux (classic fireball model) is probably dominated by the
Blandford-Znajek energy flux, which predicts a jet Lorentz factor of
$\Gamma\sim 100-1000$. We show that radiatively inefficient AGN, such as M87,
are synchrotron-cooling limited to $\Gamma\sim 2-10$. Radiatively efficient
x-ray binaries, such as GRS1915+105, are Compton-drag limited to $\Gamma
\lesssim 2$, but the jet may be destroyed by Compton drag. However, the
Poynting-baryon jet is a collimated outflow with $\Gamma \sim 1-3$. The jet
from radiatively efficient systems, such as microquasar GRS1915+105, may
instead be a Poynting-baryon jet that is only relativistic when the disk is
geometrically thick. In a companion paper, general relativistic hydromagnetic
simulations of black hole accretion with pair creation are used to simulate jet
formation in GRBs, AGN, and x-ray binaries.

\\ ( http://arXiv.org/abs/astro-ph/0506368 , 406kb)

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Paper: astro-ph/0506369
Date: Thu, 16 Jun 2005 06:13:47 GMT (619kb)

Title: Jet Formation in Black Hole Accretion Systems II: Numerical Models

Authors: Jonathan C. McKinney
Comments: 20 pages, 12 figures, submitted to ApJ
\\
In a companion theory paper, we presented a unified model of jet formation.
We suggested that primarily two types of relativistic jets form near accreting
black holes: a potentially ultrarelativistic Poynting-dominated jet and a
Poynting-baryon jet. We showed that, for the collapsar model, the
neutrino-driven enthalpy flux (classic fireball model) is probably dominated by
the Blandford-Znajek energy flux, which predicts a jet Lorentz factor of
$\Gamma\sim 100-1000$. We showed that radiatively inefficient AGN, such as M87,
are synchrotron-cooling limited to $\Gamma\sim 2-10$. Radiatively efficient
x-ray binaries, such as GRS1915+105, are Compton-drag limited to $\Gamma
\lesssim 2$, but the jet may be destroyed by Compton drag. However, the
Poynting-baryon jet is a collimated outflow with $\Gamma \sim 1-3$. Here we
present general relativistic hydromagnetic simulations of black hole accretion
with pair creation used to simulate jet formation in GRBs, AGN, and x-ray
binaries. Our collapsar model shows the development of a patchy ``magnetic
fireball'' with typically $\Gamma\sim 100-1000$ and a Gaussian structure.
Temporal variability of the jet is dominated by toroidal field instabilities
for $\gtrsim 10^2$ gravitational radii. A broader Poynting-baryon jet with
$\Gamma\sim 1.5$ could contribute to a supernova.

\\ ( http://arXiv.org/abs/astro-ph/0506369 , 619kb)