Search Publications
A global climate model of Titan's atmosphere and surface
West, Robert A.; Orton, Glenn S.; Friedson, A. James +2 more
We present the formulation of a global climate model (GCM) of Titan's atmosphere and surface and report initial results. The model is a fully three-dimensional, modified version of NCAR's terrestrial global climate model, CAM3. It includes forcing by Saturn's gravitational tides; a treatment of the planetary boundary layer and surface interactions…
Iron Emission Lines on the Galactic Ridge Observed with Suzaku
Koyama, Katsuji; Ezoe, Yuichiro; Yamasaki, Noriko Y. +5 more
In order to elucidate the origin of galactic ridge X-ray emission, we analyzed Suzaku data taken at various regions along the galactic plane, and studied their Fe-K emission line features. Suzaku resolved the Fe line complex into three narrow lines at ∼6.4keV, ∼6.7keV and ∼6.97keV, which are K-lines from neutral (or low-ionized), He-like, and H-li…
Discovery of a 30-d period in the supergiant fast X-ray transient SAX J1818.6-1703
Hill, A. B.; Bird, A. J.; McBride, V. A. +4 more
SAX J1818.6-1703 has been characterized as a supergiant fast X-ray transient system on the basis of several INTEGRAL/IBIS detections since the original BeppoSAX Wide Field Camera detection. Using IBIS/ISGRI, Swift/BAT and archival observations, we show that, in fact, SAX J1818.6-1703 exhibits emission on a period of 30 +/- 0.1 d, with a high degre…
Saturn's equinoctial auroras
Dougherty, M. K.; Kurth, W. S.; Mitchell, D. G. +13 more
We present the first images of Saturn's conjugate equinoctial auroras, obtained in early 2009 using the Hubble Space Telescope. We show that the radius of the northern auroral oval is ∼1.5° smaller than the southern, indicating that Saturn's polar ionospheric magnetic field, measured for the first time in the ionosphere, is ∼17% larger in the nort…
Stratigraphy of Promethei Lingula, south polar layered deposits, Mars, in radar and imaging data sets
Plaut, J. J.; Picardi, G.; Safaeinili, A. +3 more
The south polar layered deposits (SPLD) of Mars have been studied through imagery for decades. Now, two subsurface sounding radar instruments have collected data: the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument on Mars Express and the Shallow Radar (SHARAD) instrument on Mars Reconnaissance Orbiter are observing…
Observations of Jovian polar auroral filaments
Nichols, J. D.; Clarke, J. T.; Grodent, D. +1 more
In this paper we report a phenomenon hitherto unobserved in Jupiter's ultraviolet polar auroras, specifically thin (∼0.6° wide), long-lived quasi-sun-aligned polar auroral filaments (PAFs) of brightness ∼100 kR spanning the highly variable region poleward of the main oval. This observation, made using Hubble Space Telescope images, is significant …
Interstellar extinction and long-period variables in the Galactic centre
Ganesh, S.; Glass, I. S.; Schultheis, M. +4 more
Aims: We derive a new map of the interstellar extinction near the Galactic Centre (GC), extending to much higher values of AV than previously available, and use the results obtained to better characterise the long-period variable star population of the region.
Methods: We take the Spitzer IRAC catalogue of GC point sources (Ramírez …
Detection of Ne VIII in an Intervening Multiphase Absorption System Toward 3C 263
Savage, Blair D.; Wakker, Bart P.; Narayanan, Anand
We report the detection of Ne VIII in an intervening multiphase absorption line system at z = 0.32566 in the Far Ultraviolet Spectroscopic Explorer spectrum of the quasar 3C 263 (zem = 0.646). The Ne VIII λ770 Å detection has a 3.9σ significance. At the same velocity, we also find absorption lines from C IV, O III, O IV, and N IV. The l…
Young Stellar Populations and Star Clusters in NGC 1705
Greggio, L.; Tosi, M.; Montegriffo, P. +4 more
We present Hubble Space Telescope (HST) photometry of the late-type dwarf galaxy NGC 1705 observed with the Wide-Field Planetary Camera 2 (WFPC2) in the F380W and F439W bands and with the Advanced Camera for Surveys/High-Resolution Channel (HRC) in the F330W, F555W, and F814W broad-band filters. We cross-correlate these data with previous ones acq…
Evolution of Physical Characteristics of Umbral Dots and Penumbral Grains
Jurčák, J.; Sobotka, M.
A time series of full-Stokes spectropolarimetric observations of the sunspot NOAA 10944, acquired with HINODE/SOT in 2007 February, is analyzed. The data were inverted using the code SIR into a series of 34 maps covering 3 hr of umbra and penumbra evolution. The retrieved maps of plasma parameters show the spatial distribution of temperature, line…