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:
The rest frame U-B and absolute B magnitude are calculated using the
Johnson response curves adopted by Fukugita, Ichikawa and Shimasaku, PASP, 107,
The plots were calculated for
- 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.
- the rest frame U-B as a function of observed (B-R).
- the rest frame U-B as a function of observed (R-I).
- The fourth column shows the K-correction that
converts R(z observed) into B(z=0) as a function of the observed (B-R).
- The fifth column shows the K correction that
converts R(z observed) into B(z=0) but now as a function of the
- 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
Last modified: Mon Nov 3 15:55:54 2003