Bahram Mobasher

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A comparative study of the rest-frame morphology and structural properties of optically selected starburst galaxies at redshift z 1 is carried out using multi-waveband (BV iz) high resolution images taken by the Advanced Camera for Surveys (ACS) as part of the Great Observatories Origins Deep Survey (GOODS). We classify galaxies into starburst, early and(More)
We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to trace the history of cosmic expansion over the last 10 billion yr. These objects, which include 13 spectro-scopically confirmed SNe Ia at z ! 1, were discovered during 14 epochs of reimaging of the GOODS fields North and South over 2 yr with the(More)
We present the first results from the Australia Telescope Large Area Survey, which consists of deep radio observations of a 3.7 deg 2 field surrounding the Chandra Deep Field–South, largely coincident with the infrared Spitzer Wide-Area Infrared Extragalactic (SWIRE) Survey. We also list cross-identifications to infrared and optical photom-etry data from(More)
Ordinary baryonic particles (such as protons and neutrons) account for only one-sixth of the total matter in the Universe. The remainder is a mysterious 'dark matter' component, which does not interact via electromagnetism and thus neither emits nor reflects light. As dark matter cannot be seen directly using traditional observations, very little is(More)
Results of a blind test of photometric redshift predictions against spectroscopic galaxy redshifts obtained in the Hubble Deep Field with the Keck Telescope are presented. The best photometric redshift schemes predict spectroscopic redshifts with a redshift accuracy of |∆z| < 0.1 for more than 68 percent of sources and with |∆z| < 0.3 for 100 percent, when(More)
We present a three-dimensional cosmic shear analysis of the Hubble Space Telescope COSMOS survey, the largest ever optical imaging program performed in space. We have measured the shapes of galaxies for the telltale distortions caused by weak gravitational lensing and traced the growth of that signal as a function of redshift. Using both 2D and 3D analyses,(More)
We present photometric redshifts for the COSMOS survey derived from a – 3 – new code, optimized to yield accurate and reliable redshifts and spectral types of galaxies down to faint magnitudes and redshifts out to z ∼ 1.2. The technique uses χ 2 template fitting, combined with luminosity function priors and with the option to estimate the internal(More)
We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to trace the history of cosmic expansion over the last 10 billion years. These objects, which include 13 spectroscopically confirmed SNe Ia at z ≥ 1, were discovered during 14 epochs of reimaging of the GOODS fields North and South over two years(More)
One-third of present-day spirals host optically visible strong bars that drive their dynamical evolution. However, the fundamental question of how bars evolve over cosmological times has yet to be resolved, and even the frequency of bars at intermediate redshifts remains controversial. We investigate the frequency of bars out to z ∼ 1 drawing on a sample of(More)