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A Study of Saturn's Ring Phase Curves from HST Observations
Poulet, F.; French, R. G.; Dones, L. +1 more
Solar phase curves between 0.3° and 6.0° and color ratios at wavelengths λ=0.336 µm and λ=0.555 µm for Saturn's rings are presented using recent Hubble Space Telescope observations. We test the hypothesis that the phase reddening of the rings is less due to collective properties of the ring particles than to the individual properties o…
Multiple X-ray reflection from ionized slabs
Fabian, A. C.; Ross, R. R.; Ballantyne, D. R.
Multiple reflection of X-rays may be important when an accretion disc and its hot corona have a complicated geometry, or if returning radiation due to gravitational light bending is important, or in emission from a funnel such as proposed in some γ-ray burst models. We simulate the effects of multiple reflection by modifying the boundary condition…
The 69-µm forsterite band as a dust temperature indicator
Waters, L. B. F. M.; Ade, P. A. R.; Barlow, M. J. +6 more
A band of pure crystalline forsterite (100 per cent Mg2SiO4) occurs at 69.67µm at room temperature (295K) for olivines with >~10 per cent Fe the corresponding feature is at >~73µm. The Mg-rich forsterite feature is observed in a variety of ISO LWS spectra, but the corresponding Fe-rich olivine feature is not…
A multiwavelength timing analysis of the eclipsing polar DP Leo
Gänsicke, B. T.; Kanbach, G.; Schwope, A. D. +2 more
We present an analysis of the X-ray light curves of the magnetic cataclysmic variable DP Leo using recently performed XMM-Newton EPIC and archival published and unpublished ROSAT/ PSPC observations. We combine the timings of the X-ray eclipses with timings derived from archival HST-observations and new optical observations with the photon counting…
High-Resolution X-Ray Spectroscopy of Hercules X-1 with the XMM-Newton Reflection Grating Spectrometer: CNO Element Abundance Measurements and Density Diagnostics of a Photoionized Plasma
Zane, S.; Ramsay, G.; Hailey, C. J. +2 more
We analyze the high-resolution X-ray spectrum of Hercules X-1, an intermediate-mass X-ray binary, which was observed with the XMM-Newton Reflection Grating Spectrometer. We measure the elemental abundance ratios by use of spectral models, and we detect material processed through the CNO cycle. The CNO abundances and, in particular, the ratio N/O&g…
The dusk flank of Jupiter's magnetosphere
Gurnett, D. A.; Dougherty, M. K.; Hospodarsky, G. B. +8 more
Limited single-spacecraft observations of Jupiter's magnetopause have been used to infer that the boundary moves inward or outward in response to variations in the dynamic pressure of the solar wind. At Earth, multiple-spacecraft observations have been implemented to understand the physics of how this motion occurs, because they can provide a snap…
Chandra HRC and HST observations of NGC 6240: resolving the active galactic nucleus and starburst
Zezas, A.; Murray, S. S.; Lira, P. +1 more
We present high spatial resolution X-ray Chandra HRC and HST WFPC2 Hα observations of the prototypical infrared-luminous galaxy NGC 6240. The central region of this system shows a remarkably complex morphology, with filaments and loops observed in the optical and X-rays. The total X-ray luminosity is dominated by the extended emission. Both nuclei…
The anomalous X-ray pulsar 1E 1048.1-5937: Phase resolved spectroscopy with the XMM-Newton satellite
Tiengo, A.; Mereghetti, S.; Staubert, R. +1 more
We report on an observation of the anomalous X-ray pulsar 1E 1048.1-5937 performed with the XMM-Newton satellite. The phase averaged spectrum of 1E 1048.1-5937 is well described by the sum of a power law with photon index ~ 2.9 and a blackbody with temperature ~ 0.6 keV, without evidence for significant absorption or emission lines. The above spec…
Wide Field Planetary Camera 2 Observations of the Polar Ring Galaxy NGC 4650A
Gallagher, J. S.; Sparke, L. S.; Kinney, A. L. +5 more
We present multicolor Wide Field Planetary Camera 2 images of the polar ring galaxy NGC 4650A (D=35 Mpc), taken with the Hubble Space Telescope. These data allow a detailed examination of the morphology of the central S0 component and the surrounding ``polar ring'' of stars, gas, and dust, which are spatially extended and form a ``polar disk.'' Th…
Polarity reversal of the solar magnetic field during cycle 23
Andrews, M. D.; Sheeley, N. R.; Wang, Y. -M.
Using magnetograph data, coronagraph observations, and source surface extrapolations, we examine the evolution of the photospheric magnetic field from 1996 through the 2000-2001 polarity reversal and show how this evolution is reflected in coronal holes, coronal streamers, the heliospheric current sheet (HCS), and the solar wind. The photospheric …