Search Publications

Cassini Imaging Science: Initial Results on Saturn's Rings and Small Satellites

Burns, J. A.; Neukum, G.; Wagner, R. +32 more

Images acquired of Saturn's rings and small moons by the Cassini Imaging Science Subsystem (ISS) during the first 9 months of Cassini operations at Saturn have produced many new findings. These include new saturnian moons; refined orbits of new and previously known moons; narrow diffuse rings in the F-ring region and embedded in gaps within the ma…

Spectroscopy of Red Giants in the Large Magellanic Cloud Bar: Abundances, Kinematics, and the Age-Metallicity Relation

Cole, Andrew A.; Tolstoy, Eline; Gallagher, John S., III +1 more

We report metallicities and radial velocities derived from spectra at the near-infrared calcium triplet for 373 red giants in a 200 arcmin² area at the optical center of the LMC bar. These are the first spectroscopic abundance measurements of intermediate-age and old field stars in the high surface brightness heart of the LMC. The metal…

A Sporadic Third Layer in the Ionosphere of Mars

Pätzold, M.; Häusler, B.; Tellmann, S. +3 more

The daytime martian ionosphere has been observed as a two-layer structure with electron densities that peak at altitudes between about 110 and 130 kilometers. The Mars Express Orbiter Radio Science Experiment on the European Mars Express spacecraft observed, in 10 out of 120 electron density profiles, a third ionospheric layer at altitude ranges o…

Evidence for a Massive Poststarburst Galaxy at z~6.5

Panagia, N.; Stern, D.; Dickinson, M. +28 more

We describe results from a search for high-redshift J-band ``dropout'' galaxies in the portion of the Great Observatories Origins Deep Survey (GOODS) southern field that is covered by extremely deep imaging from the Hubble Ultradeep Field (HUDF). Using observations at optical, near-infrared, and mid-infrared wavelengths from the Hubble and Spitzer…

An overview of the descent and landing of the Huygens probe on Titan

Lebreton, Jean-Pierre; Witasse, Olivier; Matson, Dennis L. +9 more

Titan, Saturn's largest moon, is the only Solar System planetary body other than Earth with a thick nitrogen atmosphere. The Voyager spacecraft confirmed that methane was the second-most abundant atmospheric constituent in Titan's atmosphere, and revealed a rich organic chemistry, but its cameras could not see through the thick organic haze. After…

Positron annihilation spectrum from the Galactic Centre region observed by SPI/INTEGRAL

Sunyaev, R.; Revnivtsev, M.; Sazonov, S. +2 more

The electron-positron annihilation spectrum observed by SPI/INTEGRAL during deep Galactic Centre region exposure is reported. The line energy (510.954+/-0.075 keV) is consistent with the unshifted annihilation line. The width of the annihilation line is 2.37 +/- 0.25 keV (full width at half-maximum), while the strength of the ortho-positronium con…

Quasi-perpendicular Shock Structure and Processes

Balogh, A.; Thomsen, M. F.; Lembège, B. +11 more

Temperatures, Winds, and Composition in the Saturnian System

Strobel, D. F.; Showalter, M. R.; Lellouch, E. +43 more

Stratospheric temperatures on Saturn imply a strong decay of the equatorial winds with altitude. If the decrease in winds reported from recent Hubble Space Telescope images is not a temporal change, then the features tracked must have been at least 130 kilometers higher than in earlier studies. Saturn's south polar stratosphere is warmer than pred…

High-Energy Gamma Rays from the Massive Black Hole in the Galactic Center

Aharonian, F.; Neronov, A.

Accreting black holes (BHs) are believed to be sites of possible particle acceleration with conditions that are also favorable for effective gamma-ray production. However, because of photon-photon pair production, only low-energy (MeV) gamma rays can escape these compact objects with typically very large compactness parameters, κ=(L/L_Edd

Interplanetary flux rope ejected from an X-ray bright point. The smallest magnetic cloud source-region ever observed

Mandrini, C. H.; van Driel-Gesztelyi, L.; Démoulin, P. +5 more

Using multi-instrument and multi-wavelength observations (SOHO/MDI and EIT, TRACE and Yohkoh/SXT), as well as computing the coronal magnetic field of a tiny bipole combined with modelling of Wind in situ data, we provide evidences for the smallest event ever observed which links a sigmoid eruption to an interplanetary magnetic cloud (MC). The tiny…