agnslim, AGN super-Eddington accretion model
A broadband spectral model for a super-Eddington black hole accretion
disc developed by
Kubota & Done (2019; KD19).
This is based on the slim disc emissivity (
Abramowicz et al., 1988;
Watarai et al., 2000;
Sadowski, 2011),
where radial advection keeps
the surface luminosity at the local Eddington limit, resulting in
rather than the expected from the
Novikov-Thorne (standard, sub-Eddington) disc emissivity. This is the
only major change from the sub-Eddington agnsed model
(Kubota & Done 2018; KD18,
an updated version of optxagnf (Done et
al. (2012)). The flow is radially
stratified, with an outer standard disc (from to ), an
inner hot Comptonising region ( to ) and an intermediate warm
Comptonising region to produce the soft X-ray excess ( to
). A minor difference from agnsed is that the disc
is assumed to extend untruncated down to the inner radius of the flow,
. This can be below the innermost stable circular orbit as
pressure forces are important. By default, the code calculates its own
expected value of given the mass accretion rate. However, we
also allow this to be a free parameter e.g. for use for the extreme super
Eddington mass accretion rates probably truncate at some radius from
strong wind mass loss. Another minor difference from agnsed is that
we do not calculate the reprocessed emission as the geometry of the
inner disc is very uncertain but it probably shields the outer flow.
The model calculates some useful quantities, such as the radius at
which the flux first goes above the local Eddington limit, and the
inner radius of the flow. These are not normally displayed but can be
seen by inputting the command chatter 20, and getting the model to
recalculate the fit e.g. by changing the normalisation to 1.0001. Set
this back to the default of chatter 10 to suppress all this
information if further fits are required.
Parameters for agnslim:
par1 |
mass, black hole mass in solar masses |
par2 |
dist, comoving (proper) distance in Mpc |
par3 |
logmdot, mdot = Mdot/Mdot_Edd where eta Mdot_Edd c = L_Edd |
par4 |
astar, dimensionless black hole spin |
par5 |
cosi, cosine of the inclination angle i for the warm Comptonising
component and the outer disc. |
par6 |
kTe_hot, electron temperature for the hot Comptonisation
component in keV. If this parameter is negative then only the
hot Comptonisation component is used. |
par7 |
kTe_warm, electron temperature for the warm Comptonisation
component in keV. If this parameter is negative then only the
warm Comptonisation component is used. |
par8 |
Gamma_hot, the spectral index of the hot Comptonisation component. |
par9 |
Gamma_warm, the spectral index of the warm Comptonisation component.
If this parameter is negative then only the outer disc
component is used. |
par10 |
R_hot, outer radius of the hot Comptonisation component in Rg |
par11 |
R_warm, outer radius of the warm Comptonisation component in Rg |
par12 |
logrout, log of the outer radius of the disc in units of Rg. If this
parameter is negative, the code will use the self gravity radius as
calculated from Laor & Netzer (1989). |
par13 |
R_in, the inner radius of the disc in Rg. If this parameter
is -1 (the default), the model will use the radius calculated from
KD19. This must be greater than R_hot for mdot greater than 6 and
greater than R_isco for mdot less than 6. |
par14 |
redshift |
norm |
this must be fixed to 1. |
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Last modified: Friday, 23-Aug-2024 13:20:40 EDT
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