K correction plots

Since we do not cover the entire spectral range of galaxies we observe, to compare the measurement of galaxies at z ~ 1 with galaxies in the Nearby Universe, we must use K-corrections. Put simply, K-corrections allow transforming the observed measurements at a redshift z, into a standard measurement at redshift zero, which we call as the rest-frame. This correction depends on the filter that was used for the observations, the filter used as a rest-frame standard, the shape of the spectral energy distribution (SED) of the galaxy, and the redshift (for a more detailed explanation on what are K-corrections please read this article by D. Hogg et al.).

In the following series of plots we calculate for each redshift, the convolution between a subset of Kinney et al. (1996) template SEDs and the CFHT 12k X 8k filters used for DEEP2. The colours of "template" galaxies are a function of the synthetic U-B (Johnson) colour at redshift zero. If you are using a Netscape browser, the rest-frame colours will be printed on the bottom of the browser (unfortunately this feature does not work on Mozilla).

Each of the columns represents:

  1. the (B-R), (R-I) colours. Also shown are DEEP2 galaxies with redshifts within 0.02 (grey dots) and 0.01 (black dots) from the nominal panel redshift.
  2. the rest frame U-B as a function of observed (B-R).
  3. the rest frame U-B as a function of observed (R-I).
  4. The fourth column shows the K-correction that converts R(z observed) into B(z=0) as a function of the observed (B-R).
  5. The fifth column shows the K correction that converts R(z observed) into B(z=0) but now as a function of the observed (R-I).
  6. the limiting absolute B magnitude as a function of rest fram U-B. The adopted apparent magnitude limit (which is fixed) is R=24.1 (AB) or R=23.885 (vega).
The rest frame U-B and absolute B magnitude are calculated using the Johnson response curves adopted by Fukugita, Ichikawa and Shimasaku, PASP, 107, 945. The plots were calculated for
cnaw@ucolick.org
Last modified: Mon Nov 3 15:55:54 2003