RSD-Bispec

This package computes the multipoles of redshift space bispectrum. There are four files

• "multipoles.py"
• "terms.py"
• "bispec_functions.py"
• "kernels.py"
• Additional "pk.dat" provides matter power spectrum calculated using CLASSS code.

Installation:

Download the package in the directory of your choice and import "multipoles.py".

Description

multipoles.py:

It is the master file. To compute any multipole user need to >> import "multipoles.py" as ml . Then, any multipole can be computed using the following form ml.multipole(l,m,k_1, mu,t,beta_1,b_1,gamma_2) The details of each argument can be found in ref[1].

"multipoles.py" imports the other mentioned files.

terms.py

It computes the R,S,T terms as described in ref[1].

bispec_functions.py

It sets the cosmological parameters. It interpolates the externally provided matter power spectrum, P(k), [pk.dat] and it can extrapolate the value of P(k) at any redshift z assuming an $\Lambda$-CDM cosmology.

kernels.py

It provides the expression of second-order standard perturbation theory (SPT) kernels as F and G in terms of $\mu = \cos(\theta)$ and $t = k_2/k_1$. The difference between F and G is also computed as dG

pk.dat

It is a data file generated by Boltzmann code CLASS which provides the matter power spectrum. The cosmological parameters used to generate "pk.dat" were set as per Planck's 2015 results[2].

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-Written by Somnath Bharadwaj, Debanjan Sarkar, Arindam Mazumdar

references:

[1] Mazumdar, Arindam and Bharadwaj, Somnath and Sarkar, Debanjan, Quantifying the Redshift Space Distortion of the Bispectrum II: Induced Non-Gaussianity at Second Order Perturbation

https://arxiv.org/abs/2005.07066

[2] Planck paper: https://arxiv.org/abs/1502.01589