Search Publications
Missions
Journals
Publication Years
Chandra and XMM-Newton Observations of a Sample of Low-Redshift FR I and FR II Radio Galaxy Nuclei
Hardcastle, M. J.; Birkinshaw, M.; Worrall, D. M. +2 more
We present spectral results from Chandra and XMM-Newton observations of a sample of 22 low-redshift (z<0.1) radio galaxies and consider whether the core emission originates from the base of a relativistic jet, or an accretion flow, or contains contributions from both. We find correlations between the unabsorbed X-ray, radio, and optical fluxes …
Hubble Space Telescope and Ground-based Observations of Type Ia Supernovae at Redshift 0.5: Cosmological Implications
Filippenko, Alexei V.; Garnavich, Peter; Riess, Adam G. +26 more
We present observations of the Type Ia supernovae (SNe) 1999M, 1999N, 1999Q, 1999S, and 1999U, at redshift z~0.5. They were discovered in early 1999 with the 4.0 m Blanco telescope at Cerro Tololo Inter-American Observatory by the High-z Supernova Search Team (HZT) and subsequently followed with many ground-based telescopes. SNe 1999Q and 1999U we…
Early and Rapid Merging as a Formation Mechanism of Massive Galaxies: Empirical Constraints
Conselice, Christopher J.
We present the results of a series of empirical computations regarding the role of major mergers in forming the stellar masses of modern galaxies based on measured galaxy merger and star formation histories from z~0.5 to 3. We reconstruct the merger history of normal field galaxies from z~3 to z~0 as a function of initial mass using published pair…
Composition and Physical Properties of Enceladus' Surface
Sotin, C.; Baines, K. H.; Nicholson, P. D. +22 more
Observations of Saturn's satellite Enceladus using Cassini's Visual and Infrared Mapping Spectrometer instrument were obtained during three flybys of Enceladus in 2005. Enceladus' surface is composed mostly of nearly pure water ice except near its south pole, where there are light organics, CO2, and amorphous and crystalline water ice, …
Joint observations by Cluster satellites of bursty bulk flows in the magnetotail
Zhang, T. L.; Dandouras, I.; Lucek, E. +9 more
Using the observations of three satellites of Cluster (C1, C3, and C4) during the periods July to October 2001 and July to October 2002, we study 209 active time bursty bulk flows (BBFs), the difference between single satellite observations and multisatellite observations, and the difference among three selection criteria (two about BBFs and one a…
Hubble Space Telescope NICMOS Observations of T Dwarfs: Brown Dwarf Multiplicity and New Probes of the L/T Transition
Burrows, Adam; Kirkpatrick, J. Davy; Burgasser, Adam J. +5 more
We present the results of a Hubble Space Telescope NICMOS imaging survey of 22 T-type field brown dwarfs. Five are resolved as binary systems with angular separations of 0.05"-0.35", and companionship is established on the basis of component F110W-F170M colors (indicative of CH4 absorption) and low probabilities of background contaminat…
The Latitudinal Distribution of Clouds on Titan
Montmessin, F.; Lebonnois, S.; Rannou, P. +1 more
Clouds have been observed recently on Titan, through the thick haze, using near-infrared spectroscopy and images near the south pole and in temperate regions near 40°S. Recent telescope and Cassini orbiter observations are now providing an insight into cloud climatology. To study clouds, we have developed a general circulation model of Titan that …
The Nitrogen Chemistry of Titan's Upper Atmosphere Revealed
Yelle, R. V.; Vuitton, V.; Anicich, V. G.
Titan's atmosphere is unique because dissociation of N2 and CH4, the primary atmospheric constituents, provides the H, C, and N atoms necessary for the synthesis of complex organic molecules. The first steps in the synthesis of organic molecules occur in the upper atmosphere where energetic photons and electrons dissociate N<…
Cepheid Distances to SNe Ia Host Galaxies Based on a Revised Photometric Zero Point of the HST WFPC2 and New PL Relations and Metallicity Corrections
Saha, A.; Tammann, G. A.; Thim, F. +2 more
With this paper we continue the preparation for a forthcoming summary report of our experiment with the HST to determine the Hubble constant using Type Ia supernovae as standard candles. Two problems are addressed. (1) We examine the need for, and determine the value of, the corrections to the apparent magnitudes of our program Cepheids in the 11 …
The unprecedented optical outburst of the quasar 3C 454.3 . The WEBT campaign of 2004-2005
Lee, C. -U.; Lähteenmäki, A.; Umana, G. +85 more
Context: .The radio quasar
Aims: .In order to follow the emission behaviour of the …