Showing papers by "I. M. Hook published in 2003"
California Institute of Technology1, Durham University2, Lawrence Berkeley National Laboratory3, Stockholm University4, Pierre-and-Marie-Curie University5, Colorado College6, University of California, Berkeley7, American Astronomical Society8, University of Tokyo9, Space Telescope Science Institute10, University of Oxford11, University of Cambridge12, Vanderbilt University13, European Southern Observatory14, University of Barcelona15, University of Texas at Austin16
TL;DR: In this article, the authors present new results on the Hubble diagram of distant type Ia supernovae (SNe Ia) segregated according to the type of host galaxy.
Abstract: We present new results on the Hubble diagram of distant type Ia supernovae (SNe Ia) segregated according to the type of host galaxy. This makes it possible to check earlier evidence for a cosmological constant by explicitly comparing SNe residing in galaxies likely to contain negligible dust with the larger sample. The cosmological parameters derived from these SNe Ia hosted by presumed dust-free early-type galaxies support earlier claims for a cosmological constant, which we demonstrate at �5σ significance, and the internal extinction implied is small even for late-type systems (AB < 0.2). Thus, our data demonstrate that host galaxy extinction is unlikely to systematically dim distant SNe Ia in a manner that would produce a spurious cosmological constant. Our analysis is based on new Hubble Space Telescope STIS ‘snapshot’ images and Keck-II echellette spectroscopy at the locations of the SNe, spanning the redshift range 0 < z < 0.8. Selecting from the sample discovered by the Supernova Cosmology Project (SCP), we classify the host galaxies of 39 distant SNe using the combination of STIS
122 citations
Centre national de la recherche scientifique1, University of Michigan2, Lawrence Berkeley National Laboratory3, Stockholm University4, University of Pennsylvania5, Indiana University6, University of California, Berkeley7, American Astronomical Society8, California Institute of Technology9, Space Telescope Science Institute10, Case Western Reserve University11, University of Cambridge12
TL;DR: In this article, a well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters.
Abstract: A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment The goal is to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters An instrument based on an integral field method with the powerful concept of imager slicing has been designed and is presented in this paper The spectrograph concept is optimized to have very high efficiency and low spectral resolution (R {approx} 100), constant through the wavelength range (035-17{micro}m), adapted to the scientific goals of the mission
5 citations