Search results for "Hubble Deep Field"
showing 4 items of 4 documents
Observational Cosmology at High Redshift
2007
Summary. I offer a brief review of the evolution and present status of our observational knowledge of the high-redshift Universe. In particular, I focus on the different methods that have been devised to select distant objects, and the observational evidence in hand to support (or else) the standard evolutionary scenario. 1 How High is High? The study of objects at cosmological distances from us started in the 1960s with the discovery and identification of quasi-stellar radiosources. The explanation of the features observed in the optical spectra of these objects as highly redshifted hydrogen lines opened the door to the very distant Universe. For the next 30 years after the discovery of qu…
Mission: Impossible (Escape from the Lyman Limit)
2003
We investigate the intrinsic opacity of high-redshift galaxies to outgoing ionising photons using high-quality photometry of a sample of 27 spectroscopically-identified galaxies of redshift 1.9<z<3.5 in the Hubble Deep Field. Our measurement is based on maximum-likelihood fitting of model galaxy spectral energy distributions-including the effects of intrinsic Lyman-limit absorption and random realizations of intervening Lyman-series and Lyman-limit absorption-to photometry of galaxies from space- and ground-based broad-band images. Our method provides several important advantages over the methods used by previous groups, including most importantly that two-dimensional sky subtraction of fai…
The three-ring structure of Supernova 1987A
1995
Radio Observations of the Hubble Deep Field South Region IV: Optical Properties of the Faint Radio Population
2008
The Australia Telescope Hubble Deep Field-South (ATHDFS) survey of the Hubble Deep Field South reaches sensitivities of ~10 miceoJyJy at 1.4, 2.5, 5.2 and 8.7 GHz, making the ATHDFS one of the deepest surveys ever performed with the Australia Telescope Compact Array. Here we present the optical identifications of the ATHDFS radio sources using data from the literature. We find that ~66% of the radio sources have optical counterparts to I = 23.5 mag. Deep HST imaging of the area identifies a further 12% of radio sources. We present new spectroscopic observations for 98 of the radio sources, and supplement these spectroscopic redshifts with photometric ones calculated from 5-band optical imag…