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Near-infrared (0.8-4.0 µm) spectroscopy of Mimas, Enceladus, Tethys, and Rhea
Brown, R. H.; Emery, J. P.; Burr, D. M. +2 more
Spectral measurements from the ground in the time leading up to the Cassini mission at Saturn provide important context for the interpretation of the forthcoming spacecraft data. Whereas ground-based observations cannot begin to approach the spatial scales Cassini will achieve, they do possess the benefits of better spectral resolution, a broader …
Far-Ultraviolet Spectroscopy of Magnetic Cataclysmic Variables
Szkody, Paula; Sion, Edward M.; Gänsicke, Boris T. +4 more
We have obtained Hubble Space Telescope (HST) STIS data for a total of 11 polars as part of a program aimed at compiling a homogeneous database of high-quality far-ultraviolet (FUV) spectra for a large number of cataclysmic variables (CVs). Of the 11 polars, eight were found in a state of low accretion activity (V347 Pav, VV Pup, V834 Cen, BL Hyi,…
Turbulence-driven Solar Wind Heating and Energization of Pickup Protons in the Outer Heliosphere
Isenberg, Philip A.
We improve and extend the ``dominant turbulence'' model of Isenberg et al., which describes the turbulent heating of the distant solar wind by the dissipation of wave energy generated by the isotropization of interstellar pickup protons. We first modify some of the detailed expressions in Isenberg et al. to fully incorporate the effects of wave di…
X-rays from accretion shocks in T Tauri stars: The case of BP Tau
Schmitt, J. H. M. M.; Ness, J. -U.; Robrade, J. +2 more
We present an XMM-Newton observation of the classical T Tauri star BP Tau. In the XMM-Newton RGS spectrum the O vii triplet is clearly detected with a very weak forbidden line indicating high plasma densities and/or a high UV flux environment. At the same time concurrent UV data point to a small hot spot filling factor suggesting an accretion funn…
Ly-α and ultraviolet emission from high-redshift gamma-ray burst hosts: to what extent do gamma-ray bursts trace star formation?
Östlin, G.; Jóhannesson, G.; Watson, D. +9 more
We report the result of a search for Lyα emission from the host galaxies of the gamma-ray bursts (GRBs) 030226 (z= 1.986), 021004 (z= 2.335) and 020124 (z= 3.198). We find that the host galaxy of GRB 021004 is an extended (around 8 kpc) strong Lyα emitter with a rest-frame equivalent width (EW) of 68+12-11Å, and a star format…
Local Correlation Tracking and the Magnetic Induction Equation
Schuck, P. W.
Recently, local correlation tracking has been applied to magnetograms to estimate photospheric velocities. This Letter demonstrates that local correlation tracking is inconsistent with the magnetic induction equation, which governs the temporal evolution of the photospheric magnetograms. A modified formulation, consistent with the magnetic inducti…
The Evolution of Coronal Mass Ejection Density Structures
Gombosi, T. I.; Lugaz, N.; Manchester, W. B., IV
We present a discussion of the time evolution of the mass and energy of a model coronal mass ejection (CME), analyzing both synthetic coronograph images and three-dimensional data of the numerical ideal magnetohydrodynamics (MHD) simulation. Our global steady state coronal model possesses high-latitude coronal holes and a helmet streamer structure…
Decomposition of the Visible and Dark Matter in the Einstein Ring 0047-2808 by Semilinear Inversion
Dye, S.; Warren, S. J.
We measure the mass density profile of the lens galaxy in the Einstein ring system 0047-2808 using our semilinear inversion method developed in an earlier paper. By introducing an adaptively gridded source plane, we are able to eliminate the need for regularization of the inversion. This removes the problem of a poorly defined number of degrees of…
The X-Ray Emissions from the M87 Jet: Diagnostics and Physical Interpretation
Perlman, Eric S.; Wilson, Andrew S.
We reanalyze the deep Chandra observations of the M87 jet, first examined by Wilson & Yang in 2002. By employing an analysis chain that also includes image deconvolution, knots HST-1 and I are fully separated from adjacent emission. We derive the spatially resolved X-ray spectrum of the jet using the most recent response functions and find sli…
Ultraviolet Imaging Spectroscopy Shows an Active Saturnian System
West, Robert A.; Colwell, Joshua E.; Pryor, Wayne R. +13 more
Neutral oxygen in the saturnian system shows variability, and the total number of oxygen atoms peaks at 4 × 1034. Saturn's aurora brightens in response to solar-wind forcing, and the auroral spectrum resembles Jupiter's. Phoebe's surface shows variable water-ice content, and the data indicate it originated in the outer solar system. Sat…