The ESO Distant Cluster Survey (EDisCS) is a photometric and spectroscopic study of the galaxy cluster population at two epochs, z ≃ 0.5 and z ≃ 0.8, drawn from the Las Campanas Distant Cluster Survey (LCDCS). We report results from the initial candidate confirmation stage of the program and use these results to probe the properties of the LCDCS. Of the 30 candidates targeted, we find statistic...

We examine the clustering of galaxies around a sample of 20 luminous low redshift (z < ∼ 0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope. The HST resolution makes possible galaxy identification brighter than V = 23.5 and as close as 2 to the quasar. We find a significant enhancement of galaxies within a projected separation of < ∼ 100 h kpc of the quasars. If w...

The gravitational lens configuration where a background galaxy is closely aligned with a foreground galaxy, can provide accurate measurement of the dark matter density profile in the foreground galaxy, free of dynamical assumptions. Currently only three such galaxy–galaxy lenses are known where the lensed source has a confirmed redshift and is reasonably bright at optical wavelengths, and there...

We describe observations of a galaxy in the field of the z = 2.483 radio galaxy 4C23.56, photometrically selected to have a spectral-energy distribution consistent with an old stellar population at the redshift of the radio galaxy. Exploration of redshift—stellar-population—reddening constraints from the photometry indicates that the galaxy is indeed at a redshift close to that of 4C23.56, that...

We present broad band surface photometry of the radio galaxy 3C270 (NGC 4261). We find a distinct dust lane in the V −R image of the galaxy, and determine its orientation and size. We use the major axis profile of the galaxy to estimate the optical depth of the dust lane, and discuss the significance of the lane to the shape of the galaxy. Subject headings: Galaxies: active; Galaxies: radio; Ga...

Methods for compression and classification of galaxy spectra, which are useful for large galaxy redshift surveys (such as the SDSS, 2dF, 6dF and VIRMOS), are reviewed. In particular, we describe and contrast three methods: (i) Principal Component Analysis, (ii) Information Bottleneck, and (iii) Fisher Matrix. We show applications to 2dF galaxy spectra and to mock semi-analytic spectra, and we d...

In a sample of thirty normal elliptical galaxies observed with the Spitzer IRS, one galaxy, NGC4697, shows strong PAH emission, but with an apparently weak 7.7 μm feature. We find that the PAH emission is confined to the central regions of the galaxy and that once a quiescent elliptical galaxy spectrum is subtracted, the PAH feature ratios are normal. We show that the PAH spectrum resembles the...

The 2dF Galaxy Redshift Survey has now been completed and has mapped the three-dimensional distribution, and hence clustering, of galaxies in exquisite detail over an unprecedentedly large (∼ 108 h−3 Mpc3) volume of the local Universe. Here we highlight some of the major results to come from studies of clustering within the survey: galaxy correlation function and power spectrum analyses and the...

(i) When was the Galaxy assembled? Is this an ongoing process? What was the merging history of the Milky Way? (ii) When did star formation occur in what is now ‘The Milky Way Galaxy’? Where did the star formation occur then? What was the stellar Initial Mass Function? (iii) How much dissipation of energy was there before and during the formation of the different stellar components of the Galaxy...

Adopting the framework of the Halo Occupation Distribution (HOD), we investigate the ability of galaxy clustering measurements to simultaneously constrain cosmological parameters and galaxy bias. Starting with a fiducial cosmological model and galaxy HOD, we calculate spatial clustering observables on a range of length and mass scales, dynamical clustering observables that depend on galaxy pecu...