Search Publications
Metallicity and Ionization in High-Velocity Cloud Complex C
Shull, J. Michael; Giroux, Mark L.; Collins, Joseph A.
We analyze HST and FUSE ultraviolet spectroscopic data for 11 sight lines passing through the infalling high-velocity cloud (HVC) Complex C. These sight lines pass through regions with H I column densities in the range NHI=1018.1-1020.1 cm-2. From [O I/H I] abundances, we find that Complex C metallicitie…
The energy transfer process in planetary flybys
Anderson, John D.; Campbell, James K.; Nieto, Michael Martin
We illustrate the energy transfer during planetary flybys as a function of time using a number of flight mission examples. The energy transfer process is rather more complicated than a monotonic increase (or decrease) of energy with time. It exhibits temporary maxima and minima with time which then partially moderate before the asymptotic conditio…
The Leo Elliptical NGC 3379: A Metal-Poor Halo Emerges
Layden, Andrew C.; Harris, William E.; Wehner, Elizabeth M. H. +1 more
We have used the ACS camera on HST to obtain (V, I) photometry for 5300 red giant stars in the halo of the dominant Leo group member NGC 3379, a galaxy usually regarded as a classic normal giant elliptical. We use this data to derive the metallicity distribution function (MDF) for its outer-halo field stars at a location centered 33 kpc from the g…
Hydration state of the Martian surface as seen by Mars Express OMEGA: 1. Analysis of the 3 µm hydration feature
Bibring, J. -P.; Gondet, B.; Langevin, Y. +5 more
Global mapping by the visible/near-infrared OMEGA spectrometer gives the first opportunity to study in detail the characteristics of the 3 µm hydration absorption on the surface of Mars. This feature is caused by bending and stretching vibrations of adsorbed or structural H2O and/or OH- bound to minerals. A specific data reduction…
Superresolving Distant Galaxies with Gravitational Telescopes: Keck Laser Guide Star Adaptive Optics and Hubble Space Telescope Imaging of the Lens System SDSS J0737+3216
Treu, Tommaso; Gavazzi, Raphaël; Marshall, Philip J. +13 more
We combine high-resolution images in four optical/infrared bands, obtained with the laser guide star adaptive optics (LGSAO) system on the Keck telescope and with the Hubble Space Telescope (HST), to study the gravitational lens system SDSS J0737+3216 (lens redshift 0.3223, source redshift 0.5812). We show that (under favorable observing condition…
Alice: The rosetta Ultraviolet Imaging Spectrograph
Parker, Joel Wm.; Stern, S. A.; Feldman, P. D. +8 more
We describe the design, performance and scientific objectives of the NASA-funded ALICE instrument aboard the ESA Rosetta asteroid flyby/comet rendezvous mission. ALICE is a lightweight, low-power, and low-cost imaging spectrograph optimized for cometary far-ultraviolet (FUV) spectroscopy. It will be the first UV spectrograph to study a comet at cl…
Discovery of a Temperature-Dependent Upflow in the Plage Region During a Gradual Phase of the X-Class Flare
Harra, Louise K.; Hara, Hirohisa; Kamio, Suguru +5 more
We present Hinode/EIS raster scan observations of the plage region taken during the gradual phase of the GOES X3.2 flare that occurred on 2006 December 13. The plage region is located 200" east of the flare arcade. The plage region has a small transient coronal hole. The transient coronal hole is strongly affected by an X-class flare, and upflows …
Detection of 13CH 3D on Titan
Bézard, Bruno; Nixon, Conor A.; Jennings, Donald E. +1 more
We report the detection of 13CH 3D in Titan's stratosphere from Cassini/CIRS infrared spectra near 8.7 µm. Fitting simultaneously the ν bands of both 13CH 3D and 12CH 3D and the ν band of CH 4, we derive a D/H ratio equal to 1.32-0.11+0.15×10 and a 12C/ <…
The Grain Impact Analyser and Dust Accumulator (GIADA) Experiment for the Rosetta Mission: Design, Performances and First Results
Fulle, M.; Rodriguez, J.; Colangeli, L. +13 more
The Grain Impact Analyser and Dust Accumulator (GIADA) onboard the ROSETTA mission to comet 67P/Churyumov-Gerasimenko is devoted to study the cometary dust environment. Thanks to the rendezvous configuration of the mission, GIADA will be plunged in the dust environment of the coma and will be able to explore dust flux evolution and grain dynamic p…
Thinning and stretching of the plasma sheet
Petrukovich, A. A.; Balogh, A.; RèMe, H. +3 more
With Cluster observations in the magnetotail we study dynamics of plasma sheet thinning and stretching during 39 intervals associated with substorm growth phases. The cross-tail current density and normal magnetic field generally scale as Bn ∼ TpNp1/2/J0, but with frequent transient variations…