Search Publications
X-ray spectra of XMM-Newton AXIS serendipitous sources
Barcons, X.; Carrera, F. J.; Mateos, S. +2 more
We have carried out a broad-band spectral analysis of X-ray sources detected serendipitously with the EPIC-pn instrument onboard XMM-Newton in AXIS fields. Our total catalogue contains 1837 X-ray sources detected in the energy band 0.5-4.5 keV down to a flux of ~ 3x 10-15 erg cm-2 s-1. Optical identifications are a…
Peak proton intensities and composition variations of heavy ions during large solar energetic particle events: Uleis observations
Gold, R. E.; Roelof, E. C.; Ho, G. C. +2 more
We have examined low energy proton and heavy ion intensities in large solar energetic particle (SEP) events from 1997 to the end of 2001 using the ULEIS instrument on ACE spacecraft. We selected 33 events that are isolated and show clear onsets at 1 AU. The optical and radio signatures for all of our events are identified and where data are availa…
Improving the spatial resolution of XMM-Newton EPIC images by direct demodulation technique}
Feng, Hua; Zhang, S. N.; Lu, F. J. +2 more
We have applied the direct demodulation technique to XMM-Newton EPIC images to achieve a higher spatial resolution; the restored images are compared with Chandra images. With the improved images we can extract spectra of fine structures in XMM-Newton data.
On the XMM-Newton spectra of soft X-ray selected QSOs
Georgantopoulos, I.; Barcons, X.; Akylas, A.
We study the XMM-Newton spectra of a sample of 32 soft X-ray selected QSOs. Our goal is to check, using the spectra of moderate redshift (z ~ 1.5), faint (f0.2-8 keV>5x 10-15 erg cm-2 s-1) broad-line QSOs, previous claims for either significant intrinsic absorption or spectral hardening at high energi…
A search for O VI in the winds of B-type stars
Massa, D.; Fullerton, A. W.; Lehner, N. +1 more
We have conducted a survey of FUSE spectra of 235 Galactic B-type stars in order to determine the boundaries in the H-R diagram for the production of the superion {O Vi} in their winds. By comparing the locations and morphology of otherwise unidentified absorption features in the vicinity of the {O Vi} resonance doublet with the bona fide wind pro…
The Energy Equation in the Lower Solar Convection Zone
Durney, Bernard R.
As a consequence of the Taylor-Proudman balance, a balance between the pressure, Coriolis and buoyancy forces in the radial and latitudinal momentum equations (that is expected to be amply satisfied in the lower solar convection zone), the superadiabatic gradient is determined by the rotation law and by an unspecified function of r, say, S'Ω<…
Flare stars in the TW Hydrae association: the HIP 57269 syste
Neuhäuser, R.; Guenther, E. W.; Hambaryan, V. +1 more
We discuss a new member candidate of the TW Hydrae association (TWA) among the stars of the Gershberg et al. ( te{gershberg}) flare star catalog. TWA is one of the closest known associations of young stars at about 60 pc. Three supposedly young flare stars are located in the same region of the sky as TWA. One of them (
Sunshine, Earthshine and Climate Change I. Origin of, and Limits on Solar Variability
Dziembowski, W. A.; Goode, Philip R.
High resolution spectroscopy of HD 207538 from Far-UV (FUSE) to Visible (SARG-TNG). A global picture of the stellar and interstellar features modeled
Leone, F.; André, M. K.; Sonnentrucker, P. +1 more
We present a detailed study of the suspected Chemically Peculiar star HD 207538 based on high resolution spectroscopy in the far Ultraviolet (1000-3350 Å) and visible (4600-7000 Å) ranges. The stellar abundance synthesis analysis was performed by using Kurucz's codes ATLAS9 and SYNTHE to compute the atmospheric model and the synthetic spectrum res…
A spherical model for computing polarized radiation in Titan's atmosphere
Keller, Horst U.; Grieger, Björn; Salinas, Santo V. +1 more
The Huygens descent through Titan's atmosphere in January 2005 will provide invaluable information about Titan's atmospheric composition and aerosol properties. The Descent Imager/Spectral Radiometer (DISR) will perform upward and downward looking radiation observations at various spectral ranges and spatial resolutions. To prepare the DISR data i…