Search Publications
Geomagnetic signatures of current wedge produced by fast flows in a plasma sheet
Dunlop, Malcolm; Zhang, Tielong; Cao, Jin-Bin +10 more
This paper uses the plasma data from Cluster and TC-1 and geomagnetic data to study the geomagnetic signatures of the current wedge produced by fast-flow braking in the plasma sheet. The three fast flows studied here occurred in a very quiet background and were accompanied by no (or weak) particle injections, thus avoiding the influences from othe…
Comparison of approximately isothermal gravitational potentials of elliptical galaxies based on X-ray and optical data
Böhringer, H.; Churazov, E.; Vikhlinin, A. +6 more
We analyse six X-ray bright elliptical galaxies, observed with Chandra and XMM-Newton, and approximate their gravitational potentials by isothermal spheres ϕ = v2c logr over a range of radii from ~0.5 to ~25 kpc. We then compare the circular speed vc derived from X-ray data with the estimators available from optica…
New Insights into the Problem of the Surface Gravity Distribution of Cool DA White Dwarfs
Tremblay, P. -E.; Bergeron, P.; Kalirai, J. S. +1 more
We review at length the longstanding problem in the spectroscopic analysis of cool hydrogen-line (DA) white dwarfs (T eff< 13,000 K) where gravities are significantly higher than those found in hotter DA stars. The first solution that has been proposed for this problem is a mild and systematic helium contamination from convective mix…
Evidence for present day gully activity on the Russell crater dune field, Mars
Hiesinger, H.; Erkeling, G.; Reiss, D. +1 more
On the basis of High Resolution Imaging Science Experiment (HiRISE) images of two successive years we observed changes of a gully on the Russell crater dune field. Within the first year the length of a ∼2 m wide incised gully channel grew about 50 m downslope, and ∼120 m within in the second year. Gully activity occurred in early spring between L<…
Contamination on Lyman continuum emission at z >~ 3: implication on the ionizing radiation evolution
Vanzella, E.; Cristiani, S.; Nonino, M. +1 more
We investigate the possibility of contamination by lower redshift interlopers in the measure of the ionizing radiation escaping from high-redshift galaxies. Taking advantage of the new ultradeep Very Large Telescope/Visible Multiobject Spectrograph U-band number counts in the Great Observatories Origins Deep Survey (GOODS)-South field, we calculat…
Martian polar and circum-polar sulfate-bearing deposits: Sublimation tills derived from the North Polar Cap
Le Mouélic, S.; Le Deit, L.; Massé, M. +3 more
Previous spectroscopic studies have shown the presence of hydrated minerals in various kinds of sedimentary accumulations covering and encircling the martian North Polar Cap. More specifically, gypsum, a hydrated calcium sulfate, has been detected on Olympia Planum, a restricted part of the Circum-Polar Dune Field. To further constrain the geograp…
Wave-Vector Dependence of Magnetic-Turbulence Spectra in the Solar Wind
Glassmeier, K. -H.; Sahraoui, F.; Goldstein, M. L. +1 more
Using four-point measurements of the Cluster spacecraft, the energy distribution was determined for magnetic field fluctuations in the solar wind directly in the three-dimensional wave-vector domain in the range |k|≤1.5×10-3rad/km. The energy distribution exhibits anisotropic features characterized by a prominently extended structure pe…
Structure and dynamics of the convective boundary layer on Mars as inferred from large-eddy simulations and remote-sensing measurements
Forget, F.; Hinson, D. P.; Spiga, A. +1 more
The structure of the Martian convective boundary layer (BL) is decribed by means of a novel approach involving both modelling and data analysis. Mars Express radio-occultation (RO) temperature profiles are compared to large-eddy simulations (LESs) performed with the Martian mesoscale model. The model combines the Martian radiative transfer, soil a…
The Origin of the Hot Gas in the Galactic Halo: Confronting Models with XMM-Newton Observations
Henley, David B.; Shelton, Robin L.; Mac Low, Mordecai-Mark +2 more
We compare the predictions of three physical models for the origin of the hot halo gas with the observed halo X-ray emission, derived from 26 high-latitude XMM-Newton observations of the soft X-ray background between l = 120° and l = 240°. These observations were chosen from a much larger set of observations as they are expected to be the least co…
Herschel reveals a Tdust-unbiased selection of z ~ 2 ultraluminous infrared galaxies
Aussel, H.; Elbaz, D.; Le Floc'h, E. +69 more
Using Herschel Photodetector Array Camera (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) observations of Lockman Hole-North and Great Observatories Origins Deep Survey-North (GOODS-N) as part of the Herschel Multi-tiered Extragalactic Survey (HerMES) project, we explore the far-infrared (IR) properties of a sample of mid-IR-selected …