Neutrino perturbation

[ivan rodriguez-montoya]

Hello everybody,

I want to study the evolution of only one perturbation [tex]\left( \delta = \frac{\delta \rho}{\rho} \right) [/tex] of neutrinos and CDM, not the complete Matter Power Spectrum (P(k)) . To this end, I add pertinent instructions to write the values of energy densities and its perturbations in a separate output file. To be more explicit, I do this

1.- I put the instruction to open my file (e.g. deltas.dat) in cmbmain.f90 --> subroutine DoSourcek. I do this before the line

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if (CP%WantScalars) call CalcScalarSources(EV,taustart)

2.- In equations.f90 --> subroutine fderivs, after line

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if (CP%Num_Nu_Massive > 0) then

I put this

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call MassiveNuVars(EV,ay,a,grho,gpres,dgrho,dgq, grhonu_t,dgrhonu_t, wnu_arr)
write (unit=111,FMT=233) a, grhonu_t,dgrhonu_t, grhoc_t, grhoc_t*clxc

As it can be noted, I previously modified subroutine MassiveNuVars to throw grhonu_t,dgrhonu_t. I have attached the resulting graphic (perturbaciones.eps).
This is of course, the expected behaviour. Nevertheless I want to see the evolution for the entire range of values of the scale factor. As it can be seen, the output was only up to a ~ 0.009.

My question: How can I obtain the entire evolution of \delta, i.e., from a=0, to a=1?

In addition: My actual motivation is to study the close relation between [tex]\Psi_{0}[/tex] (first moment in the expansion of the phase-space distribution function perturbation) and [tex]\delta_{\nu}[/tex]. Some comments and advice to this respect would be appreciated.

I want to thank Antony Lewis for previous replay and in advance, everybody for your helpful attention.

[Antony Lewis]

See the commented example code at the beginning of CalcScalarSources.

Also the transfer functions output when get_transfer = T already includes neutrinos and can be generated for any specific redshift.