set_xscosmo¶
-
sherpa.astro.xspec.
set_xscosmo
(h0, q0, l0)[source] [edit on github]¶ Set the cosmological parameters used by X-Spec models.
Set the cosmological parameters (H_0, q_0, lambda_0) used by X-Spec. It is equivalent to the X-Spec
cosmo
command [1]. The default values are h0=70, q0=0, and l0=0.73Parameters: - h0 (number) – The Hubble constant in km/s/Mpc.
- q0 (number) – The deceleration parameter.
- l0 (number) – The cosmological constant. If this is non-zero then the q0 parameter is ignored and the Universe is assumed to be flat.
See also
References
[1] http://heasarc.nasa.gov/xanadu/xspec/manual/XScosmo.html Note that this may refer to a newer version than the compiled version used by Sherpa; use get_xsversion to check. Examples
>>> set_xscosmo(73, 0, 0.73)