COSMOMC: redshift of power spectrum data

[Michael Drinkwater]

This is probably trivial, but how is the redshift of power spectrum data specified?

All I can find is the mean redshift in subroutine compute_scaling_factor(Ok,Ol,w,a) in mpk.f90, and nothing in the sdss_lrgDR4.dataset files. Is the value in mpk.f90 the only place it appears?

I'm a new user: trying to understand the existing data structure prior to trying to add some new data. I'm working with the June 08 version.
Thanks!

[Antony Lewis]

Check CMB_Cls_simple.f90. Mostly it calculates a range of redshifts and then interpolates to any required value.

[Michael Drinkwater]

Thanks! (getting back to this after a long break!)

My aim here is to understand how the mean redshift of the 2dF LSS observed mpk is given to the code that makes the model mpk. (I have the LRG option off when compiling.)

I found where CMB_Cls_simple sets up the transfer redshifts for CAMB, although with cmbtypes.f90 setting matter_power_maxz = 0. & matter_power_lnzsteps = 1 when not running the LRG option, it looks like it only models the z=0 mpk.

Assuming I changed these settings in cmbtypes.f90 to model the mpk at a range of redshifts, I still can't see how it calculates the model power spectrum at the redshift of the observed power spectrum. The calculation happens in mpk.f90/LSS_mpklike but that gets the model from cmbtypes.f90/MatterPowerAt which is at z=0, not the redshift of the data. Is the 2dF option incomplete? (I have the Jan 2010 version.)

cheers Michael.

[Antony Lewis]

This may have changed in the latest version. But to the extent to which the evolution is scale-independent, as long as you marginalize over the bias it doesn't matter which low redshift you choose to evaluate the power spectrum at for linear-theory results.

I didn't actually write any of the recent mpk modules, so other people may be able to help more.