New MGCAMB tests of gravity with CosmoMC and Cobaya

We present a new version of MGCAMB, a patch for the Einstein-Boltzmann solver CAMB for cosmological tests of gravity. New features include a new cubic-spline parameterization allowing for a simultaneous reconstruction of & mu;, E and the dark energy density fraction S2X as functions of redshift, the option to work with a direct implementation of & mu;, E (instead of converting to & mu;,-y first), along with the option to test models with a scalar field coupled only to dark matter, and the option to include dark energy perturbations when working with w =6 -1 backgrounds, to restore consistency with CAMB in the GR limit. This version of MGCAMB comes with a Python wrapper to run it directly from the Python interface, an implementation in the latest version of CosmoMC, and can be used with Cobaya.

Automated summary

This article introduces a new version of MGCAMB, a patch for the Einstein-Boltzmann solver CAMB used for cosmological tests of gravity. The new version features several improvements, including a new cubic-spline parameterization, the option to work with a direct implementation of & mu;, E, testing models with a scalar field coupled only to dark matter, and including dark energy perturbations to restore consistency with CAMB in the GR limit.