Search Publications
Cepheid Calibrations from the Hubble Space Telescope of the Luminosity of Two Recent Type Ia Supernovae and a Redetermination of the Hubble Constant
Filippenko, Alexei V.; Riess, Adam G.; Challis, Peter M. +6 more
We report observations of two nearby Type Ia supernovae (SNe Ia) for which observations of Cepheid variables in the host galaxies have been obtained with the Hubble Space Telescope: SN 1994ae in NGC 3370 and SN 1998aq in NGC 3982. For NCG 3370, we used the Advanced Camera for Surveys to observe 64 Cepheids that yield a distance of 29 Mpc, the fart…
The Hubble Deep Field North SCUBA Super-map - III. Optical and near-infrared properties of submillimetre galaxies
Dickinson, Mark; Mobasher, Bahram; Pope, Alexandra +3 more
We present a new submillimetre (submm) super-map in the Hubble Deep Field North (HDF-N) region (Great Observatories Origins Deep Survey North, GOODS-N, field), containing 40 statistically robust sources at 850µm. This map contains additional data, and several new sources, including one of the brightest blank-sky extragalactic submm sources e…
Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan
Rodriguez, S.; Sotin, C.; Brown, R. H. +23 more
Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5bar (ref. 1) and, similar to the Earth, N2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 107years (ref. 3). This short timescale has led to…
Multiphase High-Velocity Clouds toward HE 0226-4110 and PG 0953+414
Tripp, Todd M.; Sembach, Kenneth R.; Savage, Blair D. +3 more
We study the physical conditions, elemental abundances, and kinematics of the high-velocity clouds (HVCs) along the sight lines toward active galaxies HE 0226-4110 and PG 0953+414 using Hubble Space Telescope Space Telescope Imaging Spectrograph and Far Ultraviolet Spectroscopic Explorer data. No 21 cm H I emission is detected in these clouds, but…
Discovery of an aurora on Mars
Bertaux, Jean-Loup; Leblanc, François; Korablev, Oleg +5 more
In the high-latitude regions of Earth, aurorae are the often-spectacular visual manifestation of the interaction between electrically charged particles (electrons, protons or ions) with the neutral upper atmosphere, as they precipitate along magnetic field lines. More generally, auroral emissions in planetary atmospheres ``are those that result fr…
Cassini Measurements of Cold Plasma in the Ionosphere of Titan
Gurnett, D. A.; Persoon, A. M.; Dougherty, M. K. +15 more
The Cassini Radio and Plasma Wave Science (RPWS) Langmuir probe (LP) sensor observed the cold plasma environment around Titan during the first two flybys. The data show that conditions in Saturn's magnetosphere affect the structure and dynamics deep in the ionosphere of Titan. The maximum measured ionospheric electron number density reached 3800 p…
Imaging Redshifts of BL Lacertae Objects
Sbarufatti, B.; Falomo, R.; Treves, A.
The HST snapshot imaging survey of 110 BL Lac objects (Urry et al.) has clearly shown that the host galaxies are massive and luminous ellipticals. The dispersion of the absolute magnitudes is sufficiently small that the measurement of the galaxy brightness becomes a valuable way of estimating their distance. This is illustrated by constructing a H…
The DEEP Groth Strip Galaxy Redshift Survey. III. Redshift Catalog and Properties of Galaxies
Weiner, Benjamin J.; Forbes, Duncan A.; Rhodes, Jason +16 more
The Deep Extragalactic Evolutionary Probe (DEEP) is a series of spectroscopic surveys of faint galaxies, targeted at understanding the properties and clustering of galaxies at redshifts z~1. We present the redshift catalog of the DEEP1 Groth Strip pilot phase of this project, a Keck LRIS survey of faint galaxies in the Groth Survey Strip imaged wi…
Transforming observational data and theoretical isochrones into the ACS/WFC Vega-mag system
Anderson, Jay; Salaris, Maurizio; Bedin, Luigi R. +5 more
We propose a zero-point photometric calibration of the data from the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) on board the Hubble Space Telescope, based on a spectrum of Vega and the most up-to-date in-flight transmission curves of the camera. This calibration is accurate at the level of a few hundredths of a magnitude. The main …
Spectral Reflectance and Morphologic Correlations in Eastern Terra Meridiani, Mars
Mangold, N.; Bibring, J. -P.; Arvidson, R. E. +7 more
The Mars Express Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) hyperspectral image data covering eastern Terra Meridiani indicate the ubiquitous presence of molecular water in etched terrain materials that disconformably overlie heavily cratered terrains and underlie the hematite-bearing plains explored by the Opportun…