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Michalychforever / lss_montepython

Various large-scale structure likelihoods for Montepython
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Exactly which spectra are being computed in these likelihoods #3

Closed alexander-reeves closed 3 years ago

alexander-reeves commented 3 years ago

Dear all,

could you describe to me exactly which specta are being computed in these likelihood functions: is this the total real space matter spectrum (as would be evaluated using the convenient function "M.pk_mm_real(cs)" in CLASS-PT). Also, is IR resummation being included? Sorry if this is a very basic question but I can't tell for the code written in the likelihoods what is being calculated.

Michalychforever commented 3 years ago

Hi Alex,

CLASS-PT computes many different spectra: matter-matter, galaxy-matter, galaxy-galaxy + matter and galaxy power spectrum multipoles in redshift space. In our BOSS likelihood we use the redshift-space multipoles. IR resummation is always included in the likelihoods. If you want to check its effect, you can play with the option 'IR resummation':'Yes' in classy.

As far as the real space spectrum of matter is concerned, you can build a likelihood with the following call:

cosmo.set(....) --- this is the usual classy call, make sure you use 'non linear':'PT' z =0 k=np.linspace(0.001,0.2,100) krange=len(k) all_theory = cosmo.get_pk_mult(k*h,z,orange)

cs = 1 (this is the dark matter effective sound speed, set to 1 for simplicity here)

Pmm = (all_theory[14]+all_theory[0] + 2. cs all_theory[10]/h * 2.) h ** 3

alexander-reeves commented 3 years ago

Thank you- that clears up what I was unsure about!