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Mass along the Line of Sight to the Gravitational Lens B1608+656: Galaxy Groups and Implications for H0
McKean, J. P.; Fassnacht, C. D.; Readhead, A. C. S. +3 more
We report the discovery of four groups of galaxies along the line of sight to the B1608+656 gravitational lens system. One group is at the redshift of the primary lensing galaxy (z=0.631) and appears to have a low mass, with eight spectroscopically confirmed members and an estimated velocity dispersion of 150+/-60 km s-1. The three othe…
Oscillatory magnetic flux tube slippage in the plasma sheet
Petrukovich, A. A.; Balogh, A.; Zhang, T. L. +4 more
Cluster observations in the magnetotail revealed an abundance of strongly inclined current sheets. We determine the magnetic configuration of a particular subset of such phenomena: a series of sheet crossings, having significantly differing inclinations and occurring during quiet conditions. These wave-like variations appear to propagate azimuthal…
Dissipation of Titan's south polar clouds
Brown, Michael E.; Trujillo, Chadwick A.; Bouchez, Antonin H. +2 more
Nearly all adaptive optics images of Titan taken between December 2001 and November 2004 showed tropospheric clouds located within 30° of the south pole. We report here on a dissipation of Titan's south polar clouds observed in twenty-nine Keck and Gemini images taken between December 2004 and April 2005. The near complete lack of south polar clou…
The Rate of Type Ia Supernovae at High Redshift
Tonry, John L.; Barris, Brian J.
We derive the rates of Type Ia supernovae (SNe Ia) over a wide range of redshifts using a complete sample from the IfA Deep Survey. This sample of more than 100 SNe Ia is the largest set ever collected from a single survey and therefore uniquely powerful for a detailed supernova rate (SNR) calculation. Measurements of the SNR as a function of cosm…
VLT/GIRAFFE spectroscopic observations of the metal-poor blue compact dwarf galaxy SBS 0335-052E
Schaerer, D.; Royer, F.; Izotov, Y. I. +3 more
Aims.We present two-dimensional spectroscopy of the extremely metal-deficient blue compact dwarf (BCD) galaxy SBS 0335-052E to study physical conditions, element abundances and kinematical properties of the ionised gas in this galaxy.
Methods: .Observations were obtained in the spectral range λ3620-9400 Å with the imaging spectrograph GIRAFFE …
The electrostatic potential of E ring particles
Beckmann, U.; Kempf, S.; Srama, R. +3 more
Saturn's E ring is remarkable not only for its huge size. Based on optical measurements the ring was surprisingly found to mainly consist of ice particles of uniform size (radii between 0.3 and 2 microns) [Nicholson et al., 1996. Observations of Saturn's ring-plane crossing in August and November. Science 272, 509-516], though the source of the ri…
Hydrogen cyanide polymers, comets and the origin of life
Matthews, Clifford N.; Minard, Robert D.
Hydrogen cyanide polymers - heterogeneous solids ranging in colour from yellow to orange to brown to black - could be major components of the dark matter observed on many bodies of the outer solar system including asteroids, moons, planets and, especially, comets. The presence on cometary nuclei of frozen volatiles such as methane, ammonia and wat…
Electron velocity distribution and lion roars in the magnetosheath
Fazakerley, A. N.; Maksimovic, M.; Schwartz, S. J. +1 more
Whistler waves which are termed "lion roars" in the magnetosheath are studied using data obtained by the Spectrum Analyser (SA) of the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment aboard Cluster. Kinetic theory is then employed to obtain the theoretical expression for the whistler wave with electron temperature anisotropy whic…
The spectral energy distribution of PKS 2004-447: a compact steep-spectrum source and possible radio-loud narrow-line Seyfert 1 galaxy
Kataoka, J.; Boller, Th.; Welsh, W. F. +10 more
An investigation of the spectral energy distribution (SED) of the compact steep-spectrum (CSS) source and possible radio-loud narrow-line Seyfert 1 galaxy (NLS1), PKS 2004-447, is presented. Five out of six well-studied radio-loud NLS1 share this dual classification [optically defined as an NLS1 with radio definition of a CSS or gigahertz-peaked s…
Differential Microlensing of the Continuum and Broad Emission Lines in SDSS J0924+0219, the Most Anomalous Lensed Quasar
Keeton, Charles R.; Schechter, Paul L.; Burles, Scott +1 more
SDSS J092455.87+021924.9 is the most glaring example of a gravitational lens with anomalous flux ratios; optical broadband photometry shows image D to be a factor of 12 fainter than expected for smooth lens potentials. We report spectroscopy showing that the anomaly is present in the broad emission line flux ratios as well. There are differences b…