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The Gemini Deep Deep Survey. VII. The Redshift Evolution of the Mass-Metallicity Relation
Juneau, S.; Glazebrook, K.; Abraham, R. G. +10 more
We have investigated the mass-metallicity (M-Z) relation using galaxies at 0.4<z<1.0 from the Gemini Deep Deep Survey (GDDS) and Canada-France Redshift Survey (CFRS). Deep K- and z'-band photometry allowed us to measure stellar masses for 69 galaxies. From a subsample of 56 galaxies, for which metallicity of the interstellar mediu…
Rain, winds and haze during the Huygens probe's descent to Titan's surface
Keller, H. U.; Küppers, M.; Thomas, N. +37 more
The irreversible conversion of methane into higher hydrocarbons in Titan's stratosphere implies a surface or subsurface methane reservoir. Recent measurements from the cameras aboard the Cassini orbiter fail to see a global reservoir, but the methane and smog in Titan's atmosphere impedes the search for hydrocarbons on the surface. Here we report …
Metallicities on the Double Main Sequence of ω Centauri Imply Large Helium Enhancement
Anderson, Jay; Bedin, Luigi R.; Recio-Blanco, Alejandra +9 more
Having shown in a recent paper that the main sequence of ω Centauri is split into two distinct branches, we now present spectroscopic results showing that the bluer sequence is less metal-poor. We have carefully combined VLT's GIRAFFE spectra of 17 stars on each side of the split into a single spectrum for each branch, with adequate signal-to-nois…
The XMM-Newton view of PG quasars. I. X-ray continuum and absorption
Guainazzi, M.; Schartel, N.; Rodríguez-Pascual, P. M. +3 more
We present results of a systematic analysis of the XMM-Newton spectra of 40 quasars (QSOs) (z≤1.72) from the Palomar-Green (PG) Bright Quasar Survey sample (MB<-23). The sample includes 35 radio-quiet quasars (RQQs) and 5 radio-loud quasars (RLQs). The analysis of the spectra above 2 keV reveals that the hard X-ray continuum emission…
Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
Luri, X.; Jorissen, A.; Turon, C. +4 more
The availability of the Hipparcos Catalogue has triggered many kinematic and dynamical studies of the solar neighbourhood. Nevertheless, those studies generally lacked the third component of the space velocities, i.e., the radial velocities. This work presents the kinematic analysis of 5952 K and 739 M giants in the solar neighbourhood which inclu…
Sulfates in the North Polar Region of Mars Detected by OMEGA/Mars Express
Bibring, Jean-Pierre; Langevin, Yves; Gondet, Brigitte +1 more
The Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) imaging spectrometer observed the northern circumpolar regions of Mars at a resolution of a few kilometers. An extended region at 240°E, 85°N, with an area of 60 kilometers by 200 kilometers, exhibits absorptions at wavelengths of 1.45, 1.75, 1.94, 2.22, 2.26, and 2.48 …
Solar EUV Experiment (SEE): Mission overview and first results
Chamberlin, Phillip C.; Woods, Thomas N.; Eparvier, Francis G. +6 more
The Solar EUV Experiment (SEE) is one of four scientific instruments on the NASA Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) spacecraft, which has been simultaneously observing the Sun and Earth's upper atmosphere since January 2002. The SEE instrument measures the irradiance of the highly variable, solar extreme ultraviolet (EU…
On the Generation, Propagation, and Reflection of Alfvén Waves from the Solar Photosphere to the Distant Heliosphere
Cranmer, S. R.; van Ballegooijen, A. A.
We present a comprehensive model of the global properties of Alfvén waves in the solar atmosphere and the fast solar wind. Linear non-WKB wave transport equations are solved from the photosphere to a distance past the orbit of the Earth, and for wave periods ranging from 3 s to 3 days. We derive a radially varying power spectrum of kinetic and mag…
Biosignatures from Earth-Like Planets Around M Dwarfs
Crisp, David; Cohen, Martin; Tinetti, Giovanna +5 more
Coupled one-dimensional photochemical-climate calculations have been performed for hypothetical Earth-like planets around M dwarfs. Visible/near-infrared and thermal-infrared synthetic spectra of these planets were generated to determine which biosignature gases might be observed by a future, space-based telescope. Our star sample included two obs…
The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei
Yang, Y.; Capak, P.; Wang, W. -H. +4 more
We use highly spectroscopically complete deep and wide-area Chandra surveys to determine the cosmic evolution of hard X-ray-selected active galactic nuclei (AGNs). For the deep fields, we supplement the spectroscopic redshifts with photometric redshifts to assess where the unidentified sources are likely to lie. We find that the median redshifts a…