CAMB: matter power-spectrum

Use of Cobaya. camb, CLASS, cosmomc, compilers, etc.
Post Reply
Patrick Valageas
Posts: 1
Joined: March 01 2007
Affiliation: CEA

CAMB: matter power-spectrum

Post by Patrick Valageas » March 01 2007

Hello,
I have run CAMB to get the matter power-spectrum at z=0. Then, from the output file I get the logarithmic power as:
read(1,'(2(tr3,e12.5))',end=991) kh,PL
DeltaL= PL*(kh**3/(2*pi**2))
where kh should be k in units of h Mpc^{-1}.
Next I used eq.(29) of Eisenstein & Hu, ApJ 496, 605 (1998) to obtain a smoother power without baryonic oscillations:
q= kh/GamP*(TCMB/2.7d0)**2
L0= log(2d0*exp(1d0)+1.8d0*q)
C0= 14.2d0+731d0/(1d0+62.5d0*q)
DLs= q**4*(L0/(L0+C0*q**2))**2
up to some normalization.
When I plot the ratio DeltaL/Ds I obtain a curve which does not only oscillate around a constant but which also grows at small k.
However, in CAMB I used a spectral index equal to 1:
initial_power_num = 1
scalar_amp(1) = 2.3e-9
scalar_spectral_index(1) = 1
scalar_nrun(1) = 0
tensor_spectral_index(1) = 0
initial_ratio(1) = 1
Is this normal ? Shouldn't the ratio DL/DLs oscillate around a constant over the range 0<k<1 h Mpc^{-1} at least ?
Thanks for your help.

Post Reply