dtrans: Transverse comoving distance

In mlpeck/cosmo: Cosmological distances

Description

Transverse comoving distance in Mpc between position (ra, dec) and reference point at position (ra0, dec0) with redshift z0.

Usage

dtrans(ra, dec, z0, ra0, dec0, ...)

Arguments

ra	Right ascension in decimal degrees
dec	Declination in decimal degrees
z0	reference redshift
ra0	reference right ascension
dec0	reference declination
...	cosmological parameters passed to dcos

Details

Either the positions (ra, dec) or (z0, ra0, dec0) can be vectors. Cosmological parameters must be named if they are used. See dcos.

Value

The comoving transverse separation in Mpc.

Author(s)

M.L. Peck

Examples

    ## A compact group of galaxies from SDSS
    
    ra <- c(53.055043, 53.053015, 53.055655, 53.053242)
    dec <- c(0.26295811, 0.26203222, 0.26371558, 0.26455499)
    z <- c(0.0860, 0.08751, 0.08686, 0.08636)
    dtrans(ra, dec, z[1], ra[1], dec[1]) ##distance from object 1
    

mlpeck/cosmo documentation built on May 23, 2019, 3:02 a.m.