• Publications
  • Influence
Star Formation Rate Indicators in the Sloan Digital Sky Survey
The Sloan Digital Sky Survey (SDSS) first data release provides a database of ?106,000 unique galaxies in the main galaxy sample with measured spectra. A sample of star-forming (SF) galaxies are
Galaxy ecology: groups and low-density environments in the SDSS and 2dFGRS
We analyse the observed correlation between galaxy environment and Halpha emission-line strength, using volume-limited samples and group catalogues of 24 968 galaxies at 0.05 < z < 0.095, drawn from
Galaxy Star Formation as a function of Environment
We study the galaxy star formation rate (SFR) as a function of environment using the SDSS EDR data. We nd that the SFR is depressed in dense environments (clusters and groups) compared to the eld. We
The Environment of Active Galactic Nuclei in the Sloan Digital Sky Survey
We present the observed fraction of galaxies with an active galactic nucleus (AGN) as a function of environment in the early data release of the Sloan Digital Sky Survey (SDSS). Using 4921 galaxies
The morphology–density relation in the Sloan Digital Sky Survey
We have studied the morphology-density relation and morphology-cluster-centric-radius relation using a volume-limited sample (0.05 < z < 0.1, Mr* < -20.5) of the Sloan Digital Sky Survey (SDSS) data.
A Large, Uniform Sample of X-Ray-emitting AGNs: Selection Approach and an Initial Catalog from the ROSAT All-Sky and Sloan Digital Sky Surveys
Many open questions in X-ray astronomy are limited by the relatively small number of objects in uniform optically identified and observed samples, especially when rare subclasses are considered or
Composite Luminosity Functions Based on the Sloan Digital Sky Survey ``Cut and Enhance'' Galaxy Cluster Catalog
We present here results on the composite luminosity functions (LF) of galaxies in the clusters of galaxies selected from the Cut and Enhance cluster catalog (CE) of the Sloan Digital Sky Survey. We
Optical and X-Ray Observations of the Merging Cluster AS1063
We present the first in-depth analysis of the massive cluster AS1063. This is one of the hottest X-ray clusters discovered to date and is undergoing a major merging event. The average temperature of
The Environment of Passive Spiral Galaxies in the SDSS
In previous work on galaxy clusters, several authors reported the discovery of an unusual population of galaxies, which have spiral morphologies, but do not show any star-formation activity. These
Morphological Butcher–Oemler Effect in the SDSS “Cut and Enhance” Galaxy Cluster Catalog
We investigate the evolution of the fractions of late type cluster galaxies as a function of redshift, using one of the largest, most uniform cluster samples available. The sample consists of 514