A. Stanford

Publications (3)0 Total impact

• Source

  Available from: adsabs.harvard.edu

  Article: Galaxy Clusters at z > 1 in the IRAC Shallow Survey

  Mark Brodwin, P. Eisenhardt, A. Gonzalez, A. Stanford, D. Stern, A. Dey, B. Jannuzi
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  ABSTRACT: The IRAC Shallow Survey (Eisenhardt et al. 2004) is a wide-field (8.5 deg2) 3.6-8 um survey in Boötes designed to study the evolution of large-scale structure since z = 2. A primary goal of the survey is to carry out a search for high redshift 1 < z < 2 galaxy clusters. In addition to the powerful cosmological constraints provided by this sample, it will permit a study of the mass assembly history in rich environments, including an investigation of the "downsizing" phenomenon reported in several recent studies (e.g. Treu et al. 2005). Our cluster search methodology consists of a wavelet decomposition of structure in dz = 0.2 photometric redshift slices. This technique takes full advantage of the extensive ancillary data in the Boötes field, and, importantly, makes no assumptions about the colours of cluster members, which are increasingly uncertain at redshifts approaching z = 2. We have discovered ~20 high-significance cluster candidates at 1 < z < 2 and are pursuing follow-up observations.
  The Journal of the Royal Astronomical Society of Canada. Royal Astronomical Society of Canada 07/2005; 99:135.
• Source

  Available from: arxiv.org

  Article: BRIGHT lights, BIG city: Massive galaxies, giant Ly-a nebulae, and proto--clusters

  W. van Breugel, M. Reuland, W. de Vries, A. Stanford, A. Dey, J. Kurk, B. Venemans, H. Rottgering, G. Miley, C. De Breuck, M. Dopita, R. Sutherland, J. Bland-Hawthorn
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  ABSTRACT: High redshift radio galaxies are great cosmological tools for pinpointing the most massive objects in the early Universe: massive forming galaxies, active super--massive black holes and proto--clusters. We report on deep narrow--band imaging and spectroscopic observations of several z > 2 radio galaxy fields to investigate the nature of giant Ly-alpha nebulae centered on the galaxies and to search for over--dense regions around them. We discuss the possible implications for our understanding of the formation and evolution of massive galaxies and galaxy clusters.
  10/2002;
• Source

  Available from: arxiv.org

  Article: Induced star formation and morphological evolution in very high redshift radio galaxies

  Wil van Breugel, A. Stanford, A. Dey, G. Miley, D. Stern, H. Spinrad, J. Graham, P. McCarthy
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  ABSTRACT: Near-infrared, sub-arcsecond seeing images obtained with the W. M. Keck I Telescope of show strong evolution at rest--frame optical} wavelengths in the morphologies of high redshift radio galaxies (HzRGs) with 1.9<z<4.4. The structures change from large--scale low surface brightness regions surrounding bright, multiple component and often radio--aligned features at z>3, to much more compact and symmetrical shapes at z<3. The linear sizes (~10 kpc) and luminosities (M_B~-20 to -22) of the individual components in the z>3 HzRGs are similar to the total sizes and luminosities of normal, radio--quiet, star forming galaxies seen at z=3--4. `R'-band, 0.1 arcsec resolution images with the Hubble Space Telescope of one of these HzRGs, 4C41.17 at z=3.800, show that at rest--frame UV wavelengths the galaxy morphology breaks up in even smaller, ~1 kpc--sized components embedded in a large halo of low surface brightness emission. The brightest UV emission is from a radio--aligned, edge-brightened feature (4C41.17-North) downstream from a bright radio knot. A narrow--band Lyman-alpha image, also obtained with HST, shows an arc--shaped Lyman-alpha feature at this same location, suggestive of a strong jet/cloud collision. Deep spectropolarimetric observations with the W. M. Keck II Telescope of 4C41.17 show that the radio--aligned UV continuum is unpolarized. (abridged)
  10/1998;