How to compute the neutrino power spectrum in CLASS

[Marcos Muniz]

Hello, and sorry in advance if this is too basic.

I've been using CLASS (with the python wrapper) for some months now without any problems because I needed the full matter and dark matter + baryons power spectra, which are straightforward to compute.

Now I find myself in the situation where I need to compute the neutrino power spectrum, for which there is no direct function and I guess I have to deal with the perturbations and transfer functions themselves. However, I'm not sure how I should do this and was wondering if someone else has been in this situation or could give me some reference on how to proceed. For example, the transfer functions in CLASS are not the usual T(k,z) ones I'm used to, where T(k->0,z) ->1, for instance.

Thank you so much in advance, any help will be very much appreciated