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Cassini RPWS observations of dust in Saturn's E Ring
Gurnett, D. A.; Kurth, W. S.; Averkamp, T. F. +1 more
The Cassini radio and plasma wave science (RPWS) instrument is sensitive to few-micron dust grains impacting on the spacecraft at relative speeds of order 10 km/s. Through the first year or so of operations in orbit at Saturn, the RPWS has made a number of both inclined and equatorial crossings of the E ring, particularly near the orbit of Encelad…
Valley formation and methane precipitation rates on Titan
Perron, J. Taylor; Lamb, Michael P.; Koven, Charles D. +3 more
Branching valley networks near the landing site of the Huygens probe on Titan imply that fluid has eroded the surface. The fluid was most likely methane, which forms several percent of Titan's atmosphere and can exist as a liquid at the surface. The morphology of the valley networks and the nature of Titan's surface environment are inconsistent wi…
Correlation Between Solar Flare Productivity and Photospheric Magnetic Field Properties. 1. Maximum Horizontal Gradient, Length of Neutral Line, Number of Singular Points
Wang, Huaning; Cui, Yanmei; Li, Rong +2 more
From a large number of SOHO/MDI longitudinal magnetograms, three physical measures including the maximum horizontal gradient, the length of the neutral line, and the number of singular points are computed. These measures are used to describe photospheric magnetic field properties including nonpotentiality and complexity, which is believed to be cl…
The Local Group Stellar Populations Archive from the Hubble Space Telescope WFPC2
Dolphin, Andrew; Holtzman, Jon A.; Afonso, Cristina
We present a database (LOGPHOT) of stellar photometry of Local Group galaxies obtained with the Hubble Space Telescope using the Wide Field Planetary Camera 2 (WFPC2). The database includes photometry from all WFPC2 observations taken through 2003 with long exposures (>500 s) in F555W and F814W, and many observations in which long exposures wer…
The Excitation of Extended Red Emission: New Constraints on Its Carrier from Hubble Space Telescope Observations of NGC 7023
Gordon, Karl D.; Sell, Paul H.; Witt, Adolf N. +3 more
The carrier of the dust-associated photoluminescence process causing ERE in many dusty interstellar environments remains unidentified. Several competing models are more or less able to match the observed broad, unstructured ERE band. We now constrain the character of the ERE carrier further by determining the wavelengths of the radiation that init…
SN 1987A after 18 Years: Mid-Infrared Gemini and Spitzer Observations of the Remnant
Kirshner, Robert P.; Arendt, Richard G.; Danziger, John +6 more
Using the Gemini South 8 m telescope, we obtained high-resolution 11.7 and 18.3 µm mid-IR images of SN 1987A on day 6526 since the explosion. All the emission arises from the equatorial ring. Nearly contemporaneous spectra obtained at 5-38 µm with the Spitzer Space Telescope show that this is thermal emission from silicate dust that co…
Clustering of Star-forming Galaxies Near a Radio Galaxy at z=5.2
Ford, H. C.; Demarco, R.; Infante, L. +39 more
We present HST ACS observations of the most distant radio galaxy known, TN J0924-2201 at z=5.2. This radio galaxy has six spectroscopically confirmed Lyα-emitting companion galaxies and appears to lie within an overdense region. The radio galaxy is marginally resolved in i775 and z850, showing continuum emission aligned with …
INTEGRAL IBIS Extragalactic Survey: Active Galactic Nuclei Selected at 20-100 keV
Walter, R.; Bird, A. J.; Ubertini, P. +10 more
Analysis of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) Core Programme and public open-time observations performed up to 2005 April provides a sample of 62 active galactic nuclei in the 20-100 keV band above a flux limit of ~1.5×10-11 ergs cm-2 s-1. Most (42) of the sources in the sample are Seyfert …
Interaction of a Moreton/EIT Wave and a Coronal Hole
Veronig, Astrid M.; Temmer, Manuela; Vršnak, Bojan +1 more
We report high-cadence Hα observations of a distinct Moreton wave observed at Kanzelhöhe Solar Observatory associated with the 3B/X3.8 flare and coronal mass ejection (CME) event of 2005 January 17. The Moreton wave can be identified in about 40 Hα frames over a period of 7 minutes. The EIT wave is observed in only one frame, but the derived propa…
The Origins of Fluorescent H2 Emission From T Tauri Stars
Herczeg, Gregory J.; Walter, Frederick M.; Johns-Krull, Christopher M. +2 more
We survey fluorescent H2 emission in HST STIS spectra of the classical T Tauri stars (CTTSs) TW Hya, DF Tau, RU Lupi, T Tau, and DG Tau, and the weak-lined T Tauri star (WTTS) V836 Tau. From each of those sources we detect between 41 and 209 narrow H2 emission lines, most of which are pumped by strong Lyα emission. H2