astropy/astropy — pull request #2757 by joergdietrich (2014-07-17 12:56:35+00:00)
Title: Add baryonic matter density paramter and its evolution to cosmology clas...

...ses

As discussed in #2707, this PR adds the baryonic density to all cosmology classes. It is a new keyword argument at class instantiation. If a cosmology does not have a value for Omega_b it is left at `None` and trying to access it raises a `ValueError`.