Last modified: December 2019

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/xskyrline.html
AHELP for CIAO 4.12 Sherpa v1

xskyrline

Context: models

Synopsis

The XSPEC kyrline model: relativistic line from axisymmetric accretion disk

Syntax

xskyrline

The xskyrline model is an additive model component.

Description

The model is described at [1] .


Example

>>> create_model_component("xskyrline", "mdl")
>>> print(mdl)

Create a component of the xskyrline model and display its default parameters. The output is:

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.a        thawed       0.9982            0            1       GM/c
   mdl.theta_o  thawed           30            0           89        deg
   mdl.rin      frozen            1            1         1000     GM/c^2
   mdl.ms       frozen            1            0            1           
   mdl.rout     frozen          400            1         1000     GM/c^2
   mdl.Erest    frozen          6.4            1           99        keV
   mdl.alpha    frozen            3          -20           20           
   mdl.beta     frozen            3          -20           20           
   mdl.rb       frozen          400            1         1000     GM/c^2
   mdl.zshift   frozen            0       -0.999           10           
   mdl.limb     frozen            1            0            2           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

a

Black Hole angular momentum, in units of GM/c.

theta_o

The observer inclination, where 0 is pole on. The units are degrees.

rin

The inner radius (units of GM/c^2).

ms

A flag that determines whether to integrate from rin (0) or to integrate emission from above the marginally-stable orbit only (1)

rout

The outer radius (units of GM/c^2).

Erest

The line energy in keV.

alpha

The accretion disk emissivity scales as r^(-alpha) for r < rb.

beta

The accretion disk emissivity scales as r^(-beta) for r > rb.

rb

The boundary radius between the inner and outer emissivity laws (units of GM/c^2).

zshift

The overall Doppler shift.

limb

0 means isotropic emission, 1 means Laor's limb darkening (1 + 0.26 mu), 2 means Haardt's limb brightening (ln(1 + 1/mu))

norm

The normalization.

Notes

This model is only available when used with XSPEC 12.10.1 or later.

Early releases of XSPEC 12.10.1 refer to the first parameter as a/M. As this is not a valid Python name, the parameter has been renamed "a" to better match other XSPEC models (after consultation with Keith Arnaud).

References

XSPEC version

CIAO 4.12 comes with support for version 12.10.1n of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;
print(xspec.get_xsversion())'
12.10.1n

Bugs

See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.