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=0.73

  • 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.


1 Note that this may refer to a newer version than the compiled version used by Sherpa; use get_xsversion to check.


>>> set_xscosmo(73, 0, 0.73)