Recent observations of SgrA* by the GRAVITY instrument have astrometrically
tracked infrared flares (IR) at distances of $10$ gravitational radii
($r_g$). In this paper, we study a model for the flares based on 3D general
relativistic magnetohydrodynamic (GRMHD) simulations of magnetically arrested
accretion disks (MADs) which exhibit violent episodes of flux escape from the
black hole magnetosphere. These events are attractive for flare modeling for
several reasons: i) the magnetically dominant regions can resist being
disrupted via magneto-rotational turbulence and shear, ii) the orientation of
the magnetic field is predominantly vertical as suggested by the GRAVITY data,
iii) magnetic reconnection associated with the flux eruptions could yield a
self-consistent means of particle heating/acceleration during the flare events.
In this analysis we track erupted flux bundles and provide distributions of
sizes, energies and plasma parameter. In our simulations, the orbits tend to
circularize at a range of radii from $5-40 r_g$. The magnetic energy
contained within the flux bundles ranges up to $\sim10^40$ erg, enough to
power IR and X-ray flares. We find that the motion within the magnetically
supported flow is substantially sub-Keplerian, in tension with the inferred
period-radius relation of the three GRAVITY flares.
Description
Flares in the Galactic center I: orbiting flux tubes in Magnetically Arrested Black Hole Accretion Disks
%0 Generic
%1 porth2020flares
%A Porth, O.
%A Mizuno, Y.
%A Younsi, Z.
%A Fromm, C. M.
%D 2020
%K a flares in sgr
%T Flares in the Galactic center I: orbiting flux tubes in Magnetically
Arrested Black Hole Accretion Disks
%U http://arxiv.org/abs/2006.03658
%X Recent observations of SgrA* by the GRAVITY instrument have astrometrically
tracked infrared flares (IR) at distances of $10$ gravitational radii
($r_g$). In this paper, we study a model for the flares based on 3D general
relativistic magnetohydrodynamic (GRMHD) simulations of magnetically arrested
accretion disks (MADs) which exhibit violent episodes of flux escape from the
black hole magnetosphere. These events are attractive for flare modeling for
several reasons: i) the magnetically dominant regions can resist being
disrupted via magneto-rotational turbulence and shear, ii) the orientation of
the magnetic field is predominantly vertical as suggested by the GRAVITY data,
iii) magnetic reconnection associated with the flux eruptions could yield a
self-consistent means of particle heating/acceleration during the flare events.
In this analysis we track erupted flux bundles and provide distributions of
sizes, energies and plasma parameter. In our simulations, the orbits tend to
circularize at a range of radii from $5-40 r_g$. The magnetic energy
contained within the flux bundles ranges up to $\sim10^40$ erg, enough to
power IR and X-ray flares. We find that the motion within the magnetically
supported flow is substantially sub-Keplerian, in tension with the inferred
period-radius relation of the three GRAVITY flares.
@misc{porth2020flares,
abstract = {Recent observations of SgrA* by the GRAVITY instrument have astrometrically
tracked infrared flares (IR) at distances of $\sim 10$ gravitational radii
($r_g$). In this paper, we study a model for the flares based on 3D general
relativistic magnetohydrodynamic (GRMHD) simulations of magnetically arrested
accretion disks (MADs) which exhibit violent episodes of flux escape from the
black hole magnetosphere. These events are attractive for flare modeling for
several reasons: i) the magnetically dominant regions can resist being
disrupted via magneto-rotational turbulence and shear, ii) the orientation of
the magnetic field is predominantly vertical as suggested by the GRAVITY data,
iii) magnetic reconnection associated with the flux eruptions could yield a
self-consistent means of particle heating/acceleration during the flare events.
In this analysis we track erupted flux bundles and provide distributions of
sizes, energies and plasma parameter. In our simulations, the orbits tend to
circularize at a range of radii from $\sim 5-40 r_g$. The magnetic energy
contained within the flux bundles ranges up to $\sim10^{40}$ erg, enough to
power IR and X-ray flares. We find that the motion within the magnetically
supported flow is substantially sub-Keplerian, in tension with the inferred
period-radius relation of the three GRAVITY flares.},
added-at = {2020-06-10T04:06:32.000+0200},
author = {Porth, O. and Mizuno, Y. and Younsi, Z. and Fromm, C. M.},
biburl = {https://www.bibsonomy.org/bibtex/2ca700952da79d099512d9d226912a54c/ericblackman},
description = {Flares in the Galactic center I: orbiting flux tubes in Magnetically Arrested Black Hole Accretion Disks},
interhash = {1a10919fa0d0f71f753eb21b358e47ac},
intrahash = {ca700952da79d099512d9d226912a54c},
keywords = {a flares in sgr},
note = {cite arxiv:2006.03658Comment: submitted to MNRAS},
timestamp = {2020-06-10T04:06:32.000+0200},
title = {
Flares in the Galactic center I: orbiting flux tubes in Magnetically
Arrested Black Hole Accretion Disks},
url = {http://arxiv.org/abs/2006.03658},
year = 2020
}