redshift: Spectroscopic and Photometric Galaxy Redshift Measurements

In merror: Accuracy and Precision of Measurements

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.

Source

<https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140013340.pdf>

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)

## Not run: 
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)

## End(Not run)

merror documentation built on Aug. 29, 2023, 5:06 p.m.