## CAMB: Matter Power Normalization Issues.

Use of Healpix, camb, CLASS, cosmomc, compilers, etc.
Aaron Brown
Posts: 3
Joined: July 08 2015
Affiliation: Reed College

### CAMB: Matter Power Normalization Issues.

Hi All,
Thanks in advance for any help.

I am attempting to output the matter power spectrum for varying values of the combined neutrino mass. With N_eff=3.046 a constant, and no mass hierarchy. Basically just varying Omega_nu.

However, CAMB spits back out the power spectrums...and the normalization seems to be off at small k (large scales). That is, there appears to be slight power suppression even at the largest scales. Certainly the power spectrums should only diverge after/around turnover?

I should point out that varying N_eff and keeping mass fixed yields expected result of proper normalization at large scales and divergence only at smaller scales.

Anyone know what's causing this norm. error for varying neutrino mass?
Thanks!

Antony Lewis
Posts: 1547
Joined: September 23 2004
Affiliation: University of Sussex
Contact:

### Re: CAMB: Matter Power Normalization Issues.

It depends on what you are keeping fixed when you vary \Omega_\nu.

Aaron Brown
Posts: 3
Joined: July 08 2015
Affiliation: Reed College

### CAMB: Matter Power Normalization Issues.

Everything.
N_eff fixed, degeneracies fixed, etc.