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sigma_r module
Compute anisotropy dispersion sigma(R,z)
Name: sigma_r
File: cosmosis-standard-library/boltzmann/sigmar/sigmar.py
Version: 1.0
Author(s):
- Scott Dodelson
URL:
Cite:
Rules:
Assumptions:
- minimal assumptions; sigma computed directly from P(k,z)
Explanation
sigma(R,z) is the variance of cosmic density fluctuations on scales
down to 8 Mpc/h.
In Fourier space is given by sigma(R,z) = \int_0^\infty W^2(k R) k^2 P(k,z) / (2 \pi)^2 dk
The P(k,z) used could in general be linear or non-linear, but usually when people
say sigma they mean the non-linear variant.
##Parameters
These parameters can be set in the module's section in the ini parameter file.
If no default is specified then the parameter is required.
Parameter | Description |
---|---|
zmin | real, minimum redshift to generate values for |
zmax | real, maximum redshift to generate values for |
dz | real, output redshift sample spacing |
rmin | real, minimum scale R in Mpc/h to generate values for |
rmax | real, maximum scale R in Mpc/h to generate values for |
dr | real, scale R spacing |
matter_power | name of section to get P(k,z) from, e.g. matter_power_lin, matter_power_nl |
crop_klim | logical, crops the klimits of the sigma integral to max(0.01/R, kmin), min(100/R, kmax) (default T) |
##Inputs
These parameters and data are inputs to the module, either supplied as parameters by the sampler or computed by some previous module. They are loaded from the data block.
Section | Parameter | Description |
---|---|---|
matter_power | k_h | real 1D array, sample values of linear spectrum in Mpc/h. Section name specified by parameter in ini file. |
z | real 1D array, redshift of linear spectrum samples. Section name specified by parameter in ini file. | |
P_k | real 2D array, linear spectrum in (Mpc/h)^{-3}. Section name specified by parameter in ini file. |
##Outputs
These parameters and data are computed as outputs from the module
Section | Parameter | Description |
---|---|---|
sigmar | R | real 1D array, scale R of output in Mpc/h |
z | real 1D array, redshift of output | |
sigma2 | real 2D array, variance sigma^2(R,z) |
Updated