Search Publications
Temporal variations in solar rotation at the bottom of the convection zone: The current status
Thompson, M. J.; Howe, R.; Komm, R. +4 more
We present the most recent results on the short-period variations in the solar rotation rate near the base of the convection zone. The 1.3-year period which was reported in the early years of solar cycle 23 appears not to persist after 2001, but there are hints of fluctuations at a different period during the declining phase of the cycle.
An Apparent Hard X-Ray Decline of CH Cygni
Ishida, Manabu; Mori, Hideyuki; Terada, Yukikatsu +4 more
CH Cygni is a symbiotic star consisting of an M giant and an accreting white dwarf, which is known to be a highly variable X-ray source with a complex, two-component, spectra. Here, we report on two Suzaku observations of CH Cyg, taken in 2006 January and May, during which the system was seen to be in a soft X-ray bright, hard X-ray faint state. B…
The Mass Distribution of the Central Stars of Planetary Nebulae in the Large Magellanic Cloud
Villaver, Eva; Shaw, Richard A.; Stanghellini, Letizia
We present the properties of the central stars from a sample of 54 planetary nebulae (PNe) observed in the Large Magellanic Cloud (LMC) with the Hubble Space Telescope Imaging Spectrograph (STIS). The Hubble Space Telescope's spatial resolution allows us to resolve the central star from its nebula (and line-of-sight stars) at the distance of the L…
Observation of enhanced X-ray emission from the CTTS AA Tauri during one transit of an accretion funnel flow
Zapatero Osorio, M. R.; Grosso, N.; Bouvier, J. +3 more
Context: Classical T Tauri stars are young solar-type stars accreting material from their circumstellar disks. Thanks to a favorable inclination of the system, the classical T Tauri star AA Tau exhibits periodic optical eclipses as the warped inner disk edge occults the stellar photosphere.
Aims: We intend to observe the X-ray and UV emission …
A bright coronal downflow seen in multi-wavelength observations: evidence of a bifurcating flux-rope?
Solanki, S. K.; Mason, H. E.; Webb, D. F. +1 more
Aims:We study the origin and characteristics of a bright coronal downflow seen after a coronal mass ejection associated with erupting prominences on 5 March 2000.
Methods: This study extends that of Tripathi et al. (2006b, A&A, 449, 369) based on the Extreme-ultraviolet Imaging Telescope (EIT), the Soft X-ray Telescope (SXT) and the Large …
Spectral scaling in the turbulent Earth's plasma sheet revisited
Nakamura, R.; Lucek, E. A.; Baumjohann, W. +6 more
Bursty bulk flow associated magnetic fluctuations exhibit at least three spectral scaling ranges in the Earth's plasma sheet. Two of the three scaling ranges can be associated with multi-scale magnetohydrodynamic turbulence between the spatial scales from ~100 km to several RE (RE is the Earth's radius). These scales include …
On the relativistic iron line and soft excess in the Seyfert 1 galaxy Markarian 335
O'Neill, Paul M.; Nandra, Kirpal; Cappi, Massimo +2 more
We report a 133-ks XMM-Newton observation of the Seyfert 1 galaxy Markarian 335. The 0.4-12 keV spectrum contains an underlying power-law continuum, a soft excess below 2 keV, and a double-peaked iron emission feature in the 6-7 keV range. We investigate the possibility that the double-peaked emission might represent the characteristic signature o…
Coordinated analyses of orbital and Spirit Rover data to characterize surface materials on the cratered plains of Gusev Crater, Mars
Arvidson, Raymond E.; Knudson, Amy; Squyres, Steven W. +11 more
Comparison of the Mars Exploration Rover Spirit's Pancam (0.4 to 1.0 µm) and Mars Express Observatoire pour la Mineralogie l'Eau, les Glaces et l'Activité (OMEGA) (0.4 to 2.5 µm) spectral reflectance data over Spirit's traverses shows that Gusev cratered plains are dominated by nanophase ferric-oxide-rich dust covering weakly altered b…
NGC 2298: a globular cluster on its way to disruption
Pulone, L.; de Marchi, G.
We have studied the stellar main sequence (MS) of the globular cluster NGC 2298 using deep HST/ACS observations in the F606W and F814W bands covering an area of 3.4 arcmin × 3.4 arcmin around the cluster centre or about twice the cluster's half-mass radius. The colour-magnitude diagram that we derive in this way reveals a narrow and well defined M…
The Faint End of the Luminosity Function in the Core of the Coma Cluster
Kavelaars, J. J.; Gwyn, Stephen D. J.; Harris, William E. +4 more
We present optical measurements of the faint end of the luminosity function in the core of the Coma Cluster. Dwarf galaxies are detected down to a limiting magnitude of R~25.75 in images taken with the Hubble Space Telescope. This represents the faintest determination of the Coma luminosity function to date. With the assumption that errors due to …