This is an R implementation of the Caustic Mass Estimator for Galaxy Clusters developed in Python by Gifford et al. A pre-cleaning of interlopers is recommended, using e.g., the shifting-gapper technique.
The caustic technique is a powerful method to infer cluster mass profiles to clustrocentric distances well beyond the virial radius. It relies in the measure of the escape velocity of the system using only galaxy redshift information. This method was introduced by Diaferio & Geller (1997) and Diaferio (1999).
Install the required libraries
install.packages(c("magicaxis", "gplots", "imager", "pracma"))
Download and source the R file functions
source("RCausticMass.R")
Run the code, here using the sample data provided with unknown values of R200 and cluster velocity dispersion
data = read.table("sample_data.txt")
data = subset(data, CID == 1)
r = run_caustic(data$dproj, data$vlos, data$zclus, r200 = NA, clus_vdisp = NA)
The smoothed phase-space of galaxies can be plotted as well
image(r$x_range, r$y_range, r$img_tot, asp = NA, las = 1, xlab = expression(R[proj] ~ (Mpc)),
ylab = expression(v[proj] ~ (km/s)))
Author: Dailer F. Morell
This code is public and may be used for research purposes.