Search Publications
High resolution science with high redshift galaxies
Hathi, N. P.; Jansen, R. A.; Driver, S. P. +4 more
We summarize the high-resolution science that has been done on high redshift galaxies with Adaptive Optics (AO) on the world’s largest ground-based facilities and with the Hubble Space Telescope (HST). These facilities complement each other. Ground-based AO provides better light gathering power and in principle better resolution than HST, giving i…
Helioseismology and the solar cycle
Howe, Rachel
Helioseismic measurements stretching back for about three decades have clearly shown that the acoustic modes are sensitive to solar-cycle changes. 2006 marks the first full 11-year cycle of continuous observations from the Global Oscillation Network Group (GONG), and 10 years of observations with the Michelson Doppler Imager (MDI) aboard the SOHO …
Saturn kilometric radiation as a monitor for the solar wind?
Dougherty, M. K.; Kurth, W. S.; McComas, D. J. +9 more
Since the Voyager mission it is known that Saturn Kilometric Radiation (SKR) is strongly influenced by external forces, i.e., the solar wind and in particular the solar wind ram pressure. Recent studies using Cassini data essentially confirmed these findings for particular periods during the first Cassini orbit of Saturn. The data coverage of SKR …
Segmentation of extreme ultraviolet solar images via multichannel fuzzy clustering
Hochedez, Jean-François; Delouille, Véronique; Barra, Vincent
The study of the variability of the solar corona and the monitoring of its traditional regions (Coronal Holes, Quiet Sun and Active Regions) are of great importance in astrophysics as well as in view of the Space Weather and Space Climate applications. Here we propose a multichannel unsupervised spatially constrained fuzzy clustering algorithm tha…
A physical interpretation of the jet-like X-ray emission from supernova remnant W49B
Ballet, J.; Miceli, M.; Bocchino, F. +4 more
In the framework of the study of supernova remnants and their complex interaction with the interstellar medium and the circumstellar material, we focus on the galactic supernova remnant W49B. Its morphology exhibits an X-ray bright elongated nebula, terminated on its eastern end by a sharp perpendicular structure aligned with the radio shell. The …
Solar wind structure in the outer heliosphere
Liu, Y.; Wang, C.; Richardson, J. D.
A solar wind parcel evolves as it moves outward, interacting with the solar wind plasma ahead of and behind it and with the interstellar neutrals. This structure varies over a solar cycle as the latitudinal speed profile and current sheet tilt change. We model the evolution of the solar wind with distance, using inner heliosphere data to predict p…
Exospheric heating by pickup ions at Titan
Ip, W. -H.; Kopp, A.; Tseng, W. -L.
Titan has a very extensive atmosphere and exosphere which interact strongly with the corotating magnetospheric plasma. Some of the new pickup ions created in the vicinity of the exosphere will re-impact the upper atmosphere causing additional energy input. Previous investigations of the atmospheric collisional interaction of the pickup ions have g…
VLBI for better gravimetry in SELENE
Noda, H.; Tamura, Y.; Tsuruta, S. +17 more
The Japanese lunar explorer SELENE (SElenological and Engineering Explorer), to be launched in 2007, will for the first time utilize VLBI observations in lunar gravimetry investigations. This will particularly improve the accuracy to which the low degree gravitational harmonics and the gravity field near the limb can be measured, and when combined…
The evolution of mirror type magnetic fluctuations in the magnetosheath based on multipoint observations
Balogh, A.; Dandouras, I.; Erdős, G. +1 more
Two orbits were selected in January February 2006 when the separation between the Cluster spacecraft was large and mirror type magnetic field fluctuations were observed by all spacecraft in different regions of the terrestrial magnetosheath. Minimum variance analysis was applied to find the mirror type fluctuations, and the amplitude of the fluctu…
Variations of the solar acoustic high-degree mode frequencies over solar cycle 23
Schou, J.; Rabello-Soares, M. C.; Korzennik, Sylvain G.
Using full-disk observations obtained with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft, we present variations of the solar acoustic mode frequencies caused by the solar activity cycle. High-degree (100 < ℓ < 900) solar acoustic modes were analyzed using global helioseismology analysis …