    The XSPEC zkerrbb model: multi-temperature blackbody model for thin accretion disk around a Kerr black hole.

xszkerrbb
The xszkerrbb model is an additive model component.

The model is described at [1] .

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

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

mdl Param Type Value Min Max Units ----- ---- ----- --- --- ----- mdl.eta frozen 0 0 1 mdl.a thawed 0.5 -0.99 0.9999 mdl.i frozen 30 0 85 deg mdl.Mbh thawed 1e+07 3 1e+10 M_sun mdl.Mdd thawed 1 1e-05 100000 M0yr mdl.z frozen 0.01 0 10 mdl.fcol frozen 2 -100 100 mdl.rflag frozen 1 -3.40282e+38 3.40282e+38 mdl.lflag frozen 1 -3.40282e+38 3.40282e+38 mdl.norm thawed 1 0 1e+24

ATTRIBUTES

The attributes for this object are:

Attribute
Definition
eta
The ratio of the disk power produced by a torque at the disk inner boundary to the disk power arising from accretion. See

[1] for more details.
a
The specific angular momentum of the black hole in units of the black hole mass M (when G=c=1). It should be in the range [-1, 1).
i
The disk inclination angle, in degrees. A face-on disk has i=0. It must be less than or equal to 85 degrees.
Mbh
The mass of the black hole, in solar masses.
Mdd
The "effective" mass accretion rate in units of M_solar/year. See [1] for more details.
z
The redshift of the black hole
fcol
The spectral hardening factor, Tcol/Teff. See [1] for more details.
rflag
A flag to switch on or off the effect of self irradiation: when greater than zero the self irradition is included, otherwise it is not. This parameter can not be thawed.
lflag
A flag to switch on or off the effect of limb darkening: when greater than zero the disk emission is assumed to be limb darkened, otherwise it is isotropic. This parameter can not be thawed.
norm
The normalization of the model. It should be fixed to 1 if the inclination, mass, and distance are frozen.

References

[1] https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelKerrbb.html

Changes in CIAO

The fcol parameter was incorrectly labelled as hd: both names can be used to access this parameter.

The default a, Mbh, fcol, and lflag parameter values have changed from 0, 1, 1.7, and 0 to 0.5, 1e7, 2.0, and 1 to match XSPEC.

XSPEC version

CIAO 4.16 comes with support for version 12.13.1e of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec; print(xspec.get_xsversion())'12.13.1e

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

December 2023