A faint galaxy redshift survey to B=24
/ Authors
/ Abstract
Using the multislit LDSS-2 spectrograph on the {\it William Herschel Telescope} we have completed a redshift survey in the magnitude range $22.5 1$ and includes the highest redshift galaxy ($z=1.108$) yet discovered in a field sample. The median redshift, $\zmed=0.46$, and form of the redshift distribution constitute compelling evidence against simple luminosity evolution as an explanation of the large excess of faint galaxies ($\simeq\times$2--4 no-evolution) seen in this magnitude range. Rather we identify the excess population as blue objects with $z\sim 0.4$ and $B$\, luminosities similar to local $L^*$ galaxies indicating a dramatic decrease in the density of such objects over the last Hubble time, confirming the trends found in brighter redshift surveys. We also find a marked absence of {\it very} low redshift galaxies ($z<$0.1) at faint limits, severely constraining any significant steepening of the local field galaxy luminosity function at low luminosities.
Journal: Monthly Notices of the Royal Astronomical Society