The Northern Sky Optical Cluster Survey: Galaxy Clusters from Five Thousand Square Degrees of DPOSS

Citation

Gal, Roy R. (2001) The Northern Sky Optical Cluster Survey: Galaxy Clusters from Five Thousand Square Degrees of DPOSS. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/5v1y-pk39. https://resolver.caltech.edu/CaltechETD:etd-10142008-144557

Abstract

Clusters of galaxies are the largest bound systems in the Universe and, as such, have been used to study how matter is distributed over extremely large scales. They provide fundamental constraints for theories of large-scale structure formation and evolution, and are valuable samples for studying galaxy evolution in dense environments. Despite their importance, the last large-area Northern sky cluster catalog was produced over forty years ago, via visual inspection of photographic plates of POSS-I, presented in George Abell's seminal 1958 paper and thesis. To remedy the limitations of this earlier work, we present a modern, objectively generated catalog of galaxy clusters drawn from the object catalogs of the three-band Digitized Second Palomar Observatory Sky Survey (DPOSS). In this thesis we have undertaken the following:

1. 1) We have created a uniform, calibrated catalog of galaxies over ten thousand square degrees, covering the entire high galactic latitude northern sky.
2. 2) From the input DPOSS galaxy catalogs, we used a simple adaptive kernel technique to create galaxy density maps, combined with a bootstrap technique to make significance maps, from which candidate galaxy clusters were selected in a model-independent fashion.
3. 3) We performed complete follow-up imaging and multislit spectroscopy for candidates from two sky survey plates (totalling ~60☐°) to assess the contamination of our catalog by spurious clusters, and to estimate the redshift distribution of the true clusters.
4. 4) We derived a robust photometric redshift estimator for the clusters, using the plate photometry in conjunction with redshifts culled from the literature as well as our own observations.
5. 5) We used our compilation of clusters with redshifts to measure the cluster-cluster correlation function to very large angular scales, in various photometric redshift shells.
6. 6) We used the large library of CCD images of Abell clusters taken for DPOSS calibration to provide photometric redshifts for these clusters, and study the evolution of the galaxy populations in clusters for 0.05 < z < 0.3.

Thesis Files