merror (version 3.0)

redshift: Spectroscopic and Photometric Galaxy Redshift Measurements

Description

The redshift observations were taken from DEEP 2 Galaxy Redshift Survey.

Usage

data(redshift)

Format

Redshift measurements are usually denoted by \(z\).

A data frame with one spectroscopic redshift measurement and six different photometric measurements (by researcher) for 1432 galaxies:

z_spec

Spectroscopic redshift

z_fink

Photometric redshift - S. Finklestein

z_font

Photometric redshift - A. Fontana

z_pfor

Photometric redshift - J. Pforr

z_salv

Photometric redshift - M. Salvator

z_wikl

Photometric redshift - T. Wiklind

z_wuyt

Photometric redshift - S. Wuyts

Details

Because the photometric methods depend on the same color information, a one-factor measurement error model incuding both the spectroscopic and photomentric measurements would not be a viable model because the photometric measurements would tend to be correlated. A two-factor model would be needed but would require at minimum replicated spectroscopic measurments.

References

Newman, Jeffrey A., Michael C. Cooper, Marc Davis, S. M. Faber, Alison L. Coil, Puragra Guhathakurta, David C. Koo et al. "The DEEP2 Galaxy Redshift Survey: Design, observations, data reduction, and redshifts." The Astrophysical Journal Supplement Series 208, no. 1 (2013): 5.

Examples

library(OpenMx)
library(merror)

data(redshift)
merror.pairs(redshift)

# estimates of accuracy and precision
#   parameters for a one-factor
#   measurement error model
head(redshift)
merror.pairs(redshift)

if (FALSE) {
red <- omx(redshift[,-1],reps=200) # Drop the spectroscopic measurements

summary(red$fit)
red$ci
red$q.boot

cplot(redshift[,-1],1,2,alpha.beta.sigma=red$abs)
}