Classifying
Objects by
Medium-Band
Observations
- a spectrophotometric
17-filter survey -
project: groups and clusters at z<1
We search for overdensities in alpha/delta/z space of the galaxy sample to identify rich groups and poor clusters in the COMBO-17 fields at redshifts ranging from z=0.1 to z~1. Redshift accuracies of ~0.03 should suffice to detect groups above the underlying density field. Several high-contrast superstructures are already known in our fields, such as
- the Abell 901/902 supercluster system at z=0.17,
- the double superstructure at z=0.666 and z=0.733 in the Chandra field,
first identified through spectroscopy of the Chandra AGN sample
(Hasinger et al.)
- further clusters at z=0.11, z=0.4 etc.
The clusters and groups found will be used to study their integrated luminosity, their location on the color-magnitude relation compared to the general field, and their composition in terms of galaxy types w.r.t. the Butcher-Oemler effect. On the Chandra field, we can furthermore study the X-ray properties of the groups using the Chandra and XMM Deep Surveys.
Contact person: Hermann-Josef Röser, MPIA
Back to COMBO-17 science page
Last update Feb 11, 2003, CW