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The Spectrum of the Solar Supergranulation: Multiple Nonwave Components
Toomre, Juri; Lisle, Jason P.; Rast, Mark P.
It has recently been suggested that the solar supergranulation undergoes oscillations, with a spectrum of superposed traveling waves of unknown origin showing excess prograde power to yield superrotation. We show here that the observed supergranular spectrum does not necessarily imply a wave origin but is instead consistent with two components of …
An XMM-Newton Observation of the High Magnetic Field Radio Pulsar PSR B0154+61
Lyne, A. G.; Gonzalez, M. E.; Kaspi, V. M. +1 more
We present the results obtained from a 31 ks XMM-Newton observation of the high magnetic field radio pulsar PSR B0154+61. This relatively nearby pulsar has an inferred dipole surface magnetic field strength of 2.1×1013 G, among the highest in the population. This makes the pulsar a possible transition object between the classical radio …
X-ray emitting class I protostars in the Serpens dark cloud
Preibisch, T.
We analyze a set of three individual XMM-Newton X-ray observation of the Serpens dark cloud. In addition to the 45 sources already reported in the analysis of the first of these XMM-Newton observations by Preibisch (\cite{Preibisch2003), the complete combined data set leads to the detection of X-ray emission from four of the 19 known class I proto…
Shocked Clouds in the Vela Supernova Remnant
Nichols, Joy S.; Slavin, Jonathan D.
Unusually strong high-excitation C I has been detected in 11 lines of sight through the Vela supernova remnant (SNR) by means of UV absorption line studies of IUE data. Most of these lines of sight lie near the western edge of the bright X-ray region of the SNR in a spatially distinct band approximately 1° by 4° oriented approximately north-south.…
Complexity of magnetic structures: Flares and cycle phase dependence
Meunier, N.
A long data set of MDI/SOHO full-disk magnetograms is analyzed to provide a large sample of active regions. The objective is to study the variations of the fractal dimension of these structures on different time scales: in relation to their activity level (spots, flares) and during the solar cycle. First, the variations of the fractal dimension of…
An intense soft excess and evidence for light bending in the luminous narrow-line quasar PHL 1092
Brandt, W. N.; Fabian, A. C.; Boller, Th. +2 more
The narrow-line quasar PHL 1092 was observed by XMM-Newton at two epochs separated by nearly 30 months. Timing analyses confirm the extreme variability observed during previous X-ray missions. A measurement of the radiative efficiency is in excess of what is expected from a Schwarzschild black hole. In addition to the rapid X-ray variability, the …
Properties of the Lower Transition Region: The Widths of Optically Allowed and Intersystem Spectral Lines
Doschek, G. A.; Feldman, U.
The widths of spectral lines in the ultraviolet (UV) and extreme ultraviolet (EUV) spectral regions that are formed in the solar transition region and corona are usually greater than the optically thin widths due to thermal Doppler broadening calculated under the assumption of ionization equilibrium. Although opacity can explain the widths of some…
The XMM-Newton/2dF survey - IV. The X-ray spectral properties of the hard sources
Georgakakis, A.; Georgantopoulos, I.; Shanks, T. +4 more
We present an analysis of the X-ray spectral properties of 61 hard X-ray-selected (2-8 keV) sources from the bright (f2-8keV > 10-14 erg cm-2 s-1)XMM-Newton/2dF survey. This comprises nine XMM-Newton pointings in the North Galactic Pole region (~1.6 deg2) and overlaps with the SDSS, 2QZ and…
[O I] 63 Micron Emission from High- and Low-Luminosity Active Galactic Nucleus Galaxies
Beichman, Charles A.; Dale, Daniel A.; Malhotra, Sangeeta +3 more
The Infrared Space Observatory (ISO) was used to search for a tracer of the warm and dense neutral interstellar medium, the [O I] 63.18 µm line, in four ultraluminous IRAS sources lying at redshifts between 0.6 and 1.4. While these sources are quasars, their infrared continuum emission suggests a substantial interstellar medium. No [O I] flu…
Photospheric and stellar wind variability in ɛ Ori (B0 Ia)
Stahl, O.; Rivinius, Th.; Orlando, S. +4 more
We provide direct observational evidence for a link between photospheric activity and perturbations in the dense inner-most stellar wind regions of the B supergiant star ɛ Ori. The results, which are relevant to our understanding of the origin of wind structure, are based on a multi-spectral line analysis of optical time-series data secured in 199…