R: Cosmological volume calculator

cosvol {celestial} | R Documentation

## Cosmological volume calculator

### Description

Given the sky area, two redshifts and the cosmology, this function calculates the comoving volume.

### Usage

    cosvol(area=60, zmax=1, zmin=0, H0=100, OmegaM=0.3, OmegaL=1-OmegaM-OmegaR, OmegaR=0,
    w0=-1, wprime=0, inunit = "deg2", ref)

### Arguments

`area` | Sky area in units of innunit (default is square degrees)
`zmax` | Maximum cosmological redshift of comoving cone.
`zmin` | Minimum cosmological redshift of comoving cone.
`H0` | Hubble constant as defined at z=0 (default is H0=100 (km/s)/Mpc)
`OmegaM` | Omega Matter (default is 0.3).
`OmegaL` | Omega Lambda (default is for a flat Universe with OmegaL = 1-OmegaM-OmegaR = 0.7).
`OmegaR` | Omega Radiation (default is 0, but OmegaM/3400 is typical).
`w0` | The value of dark energy equation of state at z=0. See `cosgrow` for more details.
`wprime` | The evolution term that governs how the dark energy equation of state evolves with redshift. See `cosgrow` for more details.
`inunit` | The units of angular area provided. Allowed options are deg2 for square degrees, amin2 for square arc minutes, asec2 for square arc seconds and rad2 or sr for steradians.
`ref` | The name of a reference cosmology to use, one of 137 / 737 / Planck / Planck13 / Planck15 / WMAP / WMAP9 / WMAP7 / WMAP5 / WMAP3 / WMAP1 / Millennium / GiggleZ. Planck=Planck15 and WMAP=WMAP9. The usage is case insensitive, so wmap9 is an allowed input. See `cosref` for details. This overrides any other settings for H0/ OmegaM and OmegaL.

### Value

A 3 element vector. The first element (voltot) specifies the comoving volume of the requested cone segment in Gpc^3, the second element (volmeanz) specifies the mean redshift when mass is uniformly distributed in the volume, the third element (volmedz) specifies the median redshift when mass is uniformly distributed in the volume.

### Author(s)

Aaron Robotham

### References

Based on the equations in:

Hogg D.W., 1999, arXiv, 9905116

Wright E.L., 2006, PASP, 118, 1711

### See Also

`cosdist`,`skyarea`, `cosmap`, `cosgrow`

### Examples

    #Approximate volume of the GAMA survey (area given in skyarea example, zmax is approx
    #limit of main galaxy sample):
    TotalGAMAvol=cosvol(293.82,0.6)[1]
    print(paste('The GAMA survey volume is ~',round(TotalGAMAvol,2),'Gpc^3'))

    #Approximate volume of SDSS (area given for DR7, zmax is approx limit of main galaxy sample):
    TotalSDSSvol=cosvol(8423,0.3)[1]
    print(paste('The SDSS survey volume is ~',round(TotalSDSSvol,2),'Gpc^3'))

    #Change of reference cosmology
    cosvol(293.82,0.6,ref='Planck')

[Package celestial version 1.4.1 Index]