96,934 research outputs found
Spectroscopy of Luminous Compact Blue Galaxies in Distant Clusters I. Spectroscopic Data
We used the DEIMOS spectrograph on the Keck II Telescope to obtain spectra of
galaxies in the fields of five distant, rich galaxy clusters over the redshift
range 0.5 < z < 0.9 in a search for luminous, compact, blue galaxies (LCBGs).
Unlike traditional studies of galaxy clusters, we preferentially targeted blue
cluster members identified via multi-band photometric pre-selection based on
imaging data from the WIYN telescope. Of the 1288 sources that we targeted, we
determined secure spectroscopic redshifts for 848 sources, yielding a total
success rate of 66%. Our redshift measurements are in good agreement with those
previously reported in the literature, except for 11 targets which we believe
were previously in error. Within our sample, we confirm the presence of 53
LCBGs in the five galaxy clusters. The clusters all stand out as distinct peaks
in the redshift distribution of LCBGs with the average number density of LCBGs
ranging from 1.65+-0.25 Mpc^-3 at z=0.55 to 3.13+-0.65 Mpc^-3 at z=0.8. The
number density of LCBGs in clustes exceeds the field desnity by a factor of
749+-116 at z=0.55; at z=0.8, the corresponding ratio is E=416+-95. At z=0.55,
this enhancement is well above that seen for blue galaxies or the overall
cluster population, indicating that LCBGs are preferentially triggered in
high-density environments at intermediate redshifts.Comment: 45 pages, 19 figures, accepted to ApJ. For Full resolution figure and
data tables, see http://www.salt.ac.za/~crawford/projects/deimos
- …