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Joachimi_Bridle_alpha module
Calculate the gradient of the galaxy luminosity function at the limiting magnitude of the survey.
Name: Joachimi_Bridle_alpha
File: cosmosis-standard-library/luminosity_function/Joachimi_Bridle_alpha/interface.py
Version: 1.0
Author(s):
- CosmoSIS team
- Simon Samuroff
URL:
Cite:
Rules:
Assumptions:
- The galaxy luminosity function is well approximated by the fitting function of Blake & Bridle (2005).
- The limiting r-band magnitude r_lim>16.9
Explanation
The gradient of the cumulative galaxy luminosity function \alpha is sensitive to both redshift and magnitude limit of the survey
considered. Joachimi & Bridle (2010) extend the fitting function of Blake & Bridle (2005) to obtain a polynomial \alpha(z, r_lim)
at a range of redshifts, where z_i is the median in redshift bin i and r_lim is the r-band magnitude limit. Note that the fitting is based on ground-based
data from the COMBO-17 survey. See Joachimi & Bridle (2010) for discussion of its applicability.
##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 |
|---|---|
| magnitude_limit | double; limiting r-band magnitude of the survey considered. default=24 |
| binned_alpha | bool; compute alpha in the survey redshift bins, rather than as a continuous funtion of redshift. default=True |
##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 |
|---|---|---|
| wl_num_density | Nz | integer; number of points used to evaluate the distribution in each redshift bin. |
| nzbin | integer; number of survey redshift bins. | |
| zmax | double; maximum redshift of the redshift distributions. | |
| bin_i | real vector; an array of Nz points evenly sampled from the galaxy redshift distribution in bin i in the range z={0...zmax}. The index ranges i={0,1...nzbin}. |
##Outputs
These parameters and data are computed as outputs from the module
| Section | Parameter | Description |
|---|---|---|
| galaxy_luminosity_function | z | real vector; redshift values of alpha(z) samples |
| alpha | real vector; gradient of the logarithmic cumulative galaxy luminosity function at the limiting magnitude. | |
| z_binned | real vector; median values of the n(z) in the survey redshift bins. | |
| alpha_binned | real vector; gradient of the logarithmic cumulative galaxy luminosity function at the limiting magnitude, evaluated at the median redshift of each bin. |
Updated