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mead module
Uses an extended Halo model to compute non-linear and baryonic power
Name: mead
File: cosmosis-standard-library/structure/mead/mead_interface.so
Version: 1.0
Author(s):
- Alexander Mead
URL: https://github.com/alexander-mead/hmcode
Cite:
Rules:
Assumptions:
- Halo model and particular extensions described in referenced paper
Explanation
In the non-linear regime (high k; small scales) predicting the matter
power spectrum is extremely challenging, as the simple predictability
of the linear regime no longer applies.
The Halo model is a formalism for making predictions in this regime.
It models structure as a collection of randomly-positioned (overlapping) blobs of
matter with a specified radial density profile (for example the NFW profile).
The correlation function of matter is then the sum of the correlation within a
halo, and the correlation between halos. The distribution of the masses and radii
of the halos then specifies a particular realization of the model.
Mead et al present an optimized variant of the Halo Model, designed to produce
accurate matter power spectra well into the non-linear regime for a wide
range of cosmological models. It is designed to fit hydrodynamical simulations
like the OWLS set of models, and thus account for both non-linear evolution
and
The model has two free input parameters (though these are set to fiducial values
if they are not otherwise specified). See Table 2 in Mead et al for the meaning
of these new parameters.
Please contact Alexander Mead if you have any difficulties with the code/models itself.
(Though the CosmoSIS team are of course happy to help with connecting the code
into CosmoSIS pipelines).
##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, min redshift to save output P(k,z) |
| zmax | Real, max redshift to save P(k,z) |
| nz | Integer, number of redshift samples in P(k,z) |
| kmin | Real, min wavenumber to save output P(k,z), in Mpc/h |
| kmax | Real, max wavenumber to save P(k,z), in Mpc/h |
| nk | Integer, number of wavenumber samples in P(k,z) |
##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 |
|---|---|---|
| cosmological_parameters | omega_b | real, baryon density fraction today |
| omega_m | real, total matter density fraction today | |
| omega_lambda | real, dark energy density fraction today | |
| h0 | real, little h Hubble parameter (H0 / (100 km/s/Mpc)) | |
| sigma_8 | real, amplitude of linear matter power at 8/h Mpc at z=0. | |
| w | real, w(z=0) equation of state of dark energy (default -1.0) | |
| halo_model_parameters | A | real, default=3.13, Minimum halo concentration |
| eta_0 | real, default=0.603, Halo bloating parameter constant term |
##Outputs
These parameters and data are computed as outputs from the module
| Section | Parameter | Description |
|---|---|---|
| matter_power_nl | k_h | real 1D array, sample values of nonlinear spectrum in Mpc/h |
| z | real 1D array, redshift of nonlinear spectrum samples | |
| P_k | real 2D array, nonlinear spectrum in (Mpc/h)^{-3} |
Updated