Henry C. Ferguson

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We have discovered 16 Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST ) and have used them to provide the first conclusive evidence for cosmic deceleration that preceded the current epoch of cosmic acceleration. These objects, discovered during the course of the GOODS ACS Treasury program, include 6 of the 7 highest redshift SNe Ia known,(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 spectroscopically confirmed SNe Ia at z 1, were discovered during 14 epochs of reimaging of theGOODSfields North and South over 2 yr with the(More)
■ Abstract The Hubble space telescope observations of the northern Hubble deep field, and more recently its counterpart in the south, provide detections and photometry for stars and field galaxies to the faintest levels currently achievable, reaching magnitudes V ∼ 30. Since 1995, the northern Hubble deep field has been the focus of deep surveys at nearly(More)
The Lyman decrement associated with the cumulative effect of H I in QSO absorption systems along the line of sight provides a distinctive feature for identifying galaxies at z ∼> 2.5. Color criteria, which are sensitive to the presence of a Lyman-continuum break superposed on an otherwise flat UV spectrum, have been shown, through Keck spectroscopy, to(More)
The Hubble Deep Field (HDF) is a Director’s Discretionary program on HST in Cycle 5 to image an undistinguished field at high Galactic latitude in four passbands as deeply as reasonably possible. These images provide the most detailed view to date of distant field galaxies and are likely to be important for a wide range of studies in galaxy evolution and(More)
Cosmic variance is the uncertainty in observational estimates of the volume density of extragalactic objects such as galaxies or quasars arising from the underlying large-scale density fluctuations. This is often a significant source of uncertainty, especially in deep galaxy surveys, which tend to cover relatively small areas. We present estimates of the(More)
This is the second of two papers reporting results from a program to determine the Hubble constant to ∼ 5% precision from a refurbished distance ladder based on extensive use of differential measurements. Here we report observations of 240 Cepheid variables obtained with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) Camera 2 through the(More)
Based on observations obtained with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under NASA contract NAS 5-26555; observations collected at the European Southern Observatory, Chile (ESO Programmes 168.A-0845, 64.O-0643,(More)