CAMB-code: neutrino and quint perturbations

[Martina Schwind]

Hello Antony,

as I wrote a few weeks ago, I want to implement this paper
http://arxiv.org/abs/astro-ph/0512367
in the Camb-Code.

I have some questions about the perturbations in CAMB:

neutrino perturbations in Nu_Integrate_L012:
- for the delt_press of the neutrinos I have an additional term, where I need the Integral without the perturbations of the Fermi-Dirac-distribution.
As far as I understood it now I just can use this nu_int_kernel(iq) (in subroutine Nu_Integrate_L012) or pert_scale and multiply it with v**n (n any order) without multiplying it with y(ind +x), which is the perturbation of the distr. function.

Am I right, that
- clxq corresponds to delta_phi?
- k*psi_prime*Z corresponds to 1/2*h_dot*phi_dot?

martina

[Martina Schwind]

I have another question:
why are the pressure perturbations not included in
the subroutine MassiveNuVars?
They are not added to the pressure of the neutrinos there...

[Martina Schwind]

As far as I see it now,the pressure pertubations are neglected in these Massive_Nu_Vasr(Out), i.e. as soon as the neutrinos are massive.

Would be happy for any comment of somebody who knows this...

martina

[Antony Lewis]

The total pressure perturbation is not needed (basically because it doesn't enter into the Poisson equation, only \delta\rho).

[Martina Schwind]

Thanks!

But it is calculated. Can I use it in the way it is calculated is it right like this? As far as I see - Yes.

To which order of v can I use these Kernel values of the integration
for other additional terms, that I want to add, to get a good approximation? In the papers that I found there was no delimiter for this w of v^w. But I guess there must be a limit where it starts not to be a good approximation any more.

Martina

[Martina Schwind]

the order of v is given by the apprix. scheme n=(-4,-2,...2) and the muliplication with nu right?
In the multiplication I get the q^n where n should be inside this scheme....