Search Publications

The statistics of foreshock cavities: results of a Cluster survey

Schwartz, S. J.; Sibeck, D. G.; Billingham, L.

We use Cluster magnetic field, thermal ion, and energetic particle observations upstream of the Earth's bow shock to investigate the occurrence patterns of foreshock cavities. Such cavities are thought to form when bundles of magnetic field connect to the quasi-parallel bow shock. Shock-processed suprathermal ions can then stream along the field, …

Removal of Titan's noble gases by their trapping in its haze

Bar-Nun, Akiva; Jacovi, Ronen

Titan's haze, formed by photolysis of C ₂H ₂, C ₂H ₄ and HCN, was found experimentally to trap Ar, Kr and Xe with efficiencies of 3.5 × 10 ^-4, 1.9 × 10 ^-3 and 6.5 × 10 ^-2 [noble gas atom]/[carbon atom] in the polymer, respectively. The rate of aerosol formation and settli…

Integral field spectroscopy of four lensed quasars: analysis of their neighborhood and evidence for microlensing

Kneib, J. -P.; Faure, C.; Alloin, D. +4 more

Context: Gravitationally lensed quasars constitute an independent tool to derive the Hubble constant through the time-delays of their different images; they offer as well the opportunity to study the mass distribution and interstellar medium of their lensing galaxies and, through microlensing due to stars in their lensing galaxy, they also allow o…

A revisit to agglomerates of early-type Hipparcos stars

Caballero, J. A.; Dinis, L.

% We study the spatial structure and sub-structure of regions rich in {Hipparcos} stars with blue B_T-V_T colours. These regions, which comprise large stellar complexes, OB associations, and young open clusters, are tracers of on-going star formation in the Galaxy. The DBSCAN (Density-Based Spatial Clustering of Applications with Noise) data clust…

Exploratory Study of the X-Ray Properties of Quasars with Intrinsic Narrow Absorption Lines

Charlton, Jane C.; Eracleous, Michael; Misawa, Toru +1 more

We have used archival Chandra and XMM-Newton observations of quasars hosting intrinsic narrow UV absorption lines (intrinsic NALs) to carry out an exploratory survey of their X-ray properties. Our sample consists of three intrinsic NAL quasars and one "mini-BAL" quasar, plus four quasars without intrinsic absorption lines for comparison. These wer…

A HST study of the environment of the Herbig Ae/Be star LkHα 233 and its bipolar jet

Ray, T. P.; Eislöffel, J.; Bacciotti, F. +3 more

Context: LkHα 233 is a Herbig Ae/Be star with a collimated bipolar jet. As such, it may be a high-mass analogue to the classical T Tauri stars and their outflows.
Aims: We investigate optical forbidden lines along the LkHα 233 jet to determine physical parameters of this jet (electron density n_e, hydrogen ionisation fraction x_e…

CCD Charge Injection Structure at Very Small Signal Levels

Prigozhin, Gregory; Kissel, Steve; Lamarr, Beverly +2 more

Lensing Probabilities for Spectroscopically Selected Galaxy-Galaxy Strong Lenses

Keeton, Charles R.; Dobler, Gregory; Bolton, Adam S. +1 more

Spectroscopic galaxy-galaxy lens searches are presently the most prolific method of identifying strong lens systems in large data sets. We study the probabilities associated with these lens searches, namely the probability of identifying a candidate with rogue [O II] emission lines in a galaxy's spectrum, and the probability that the candidate wil…

Deviations from the Flux-Recurrence Time Relationship in GS 1826-238: Potential Transient Spectral Changes

Rothschild, Richard E.; Galloway, Duncan K.; Homer, Lee +1 more

The low-mass X-ray binary GS 1826-238 is presently unique for its consistently regular bursting behavior. In previous Rossi X-Ray Timing Explorer (RXTE) measurements between 1997 November and 2002 July, this source exhibited (nearly) limit-cycle bursts with recurrence times that decreased proportionately as the persistent flux increased. Here we r…

Dielectric properties of the Martian south polar layered deposits: MARSIS data inversion using Bayesian inference and genetic algorithm

Nielsen, Erling; Zhang, Zhenfei; Plaut, Jeffrey J. +3 more

Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) has offered abundant data, which have been used to estimate dielectric properties of the south polar layered deposits (SPLD) of Mars. This paper presents a new way to invert the data to estimate the dielectric properties of the SPLD. A total of 4364 measurements were analyzed. The…