Search Publications
On the Limb Darkening, Spectral Energy Distribution, and Temperature Structure of Procyon
Ludwig, H. -G.; Kervella, P.; Aufdenberg, J. P.
We have fit synthetic visibilities from three-dimensional (CO5BOLD+PHOENIX) and one-dimensional (PHOENIX, ATLAS 12) model stellar atmospheres of Procyon (F5 IV) to high-precision interferometric data from the VLT Interferometer (K band) and from the Mark III interferometer (500 and 800 nm). These data sets provide a test of theoretical …
Intrinsic Curvature in the X-Ray Spectra of BL Lacertae Objects
Perlman, Eric S.; Georganopoulos, Markos; Stocke, John T. +10 more
We report results from XMM-Newton observations of 13 X-ray bright BL Lacertae objects, selected from the Einstein Slew Survey sample (SSS). The survey was designed to look for evidence of departures of the X-ray spectra from a simple power-law shape (i.e., curvature and/or line features) and to find objects worthy of deeper study. Our data are gen…
A 5-Micron-Bright Spot on Titan: Evidence for Surface Diversity
Drossart, Pierre; Sotin, Christophe; Sicardy, Bruno +32 more
Observations from the Cassini Visual and Infrared Mapping Spectrometer show an anomalously bright spot on Titan located at 80°W and 20°S. This area is bright in reflected light at all observed wavelengths, but is most noticeable at 5 microns. The spot is associated with a surface albedo feature identified in images taken by the Cassini Imaging Sci…
Quasi thermal noise spectroscopy in the inner magnetosphere of Saturn with Cassini/RPWS: Electron temperatures and density
Moncuquet, Michel; Meyer-Vernet, Nicole; Lecacheux, Alain +2 more
On 1 July 2004, the Cassini spacecraft performed its Saturn orbit insertion, twice crossing the equatorial plane between the G and F rings. The radio HF receiver observed a peak at the upper-hybrid frequency and weakly banded emissions having well-defined minima at gyroharmonics. We show that through most of the encounter, these emissions do not r…
The HIA instrument on board the Tan Ce 1 Double Star near-equatorial spacecraft and its first results
Lundin, R.; Dandouras, I.; Klecker, B. +16 more
On 29 December 2003, the Chinese spacecraft Tan Ce 1 (TC-1), the first component of the Double Star mission, was successfully launched within a low-latitude eccentric orbit. In the framework of the scientific cooperation between the Academy of Sciences of China and ESA, several European instruments, identical to those developed for the Cluster spa…
Ultraviolet, X-Ray, and Optical Radiation from the Geminga Pulsar
Romani, R. W.; Pavlov, G. G.; Zavlin, V. E. +1 more
We observed the γ-ray pulsar Geminga with the FUV-MAMA and NUV-MAMA detectors of the Space Telescope Imaging Spectrometer to measure Geminga's spectrum and pulsations in the ultraviolet. The slope of the far-ultraviolet (FUV) spectrum is close to that of a Rayleigh-Jeans spectrum, suggesting that the FUV radiation is dominated by thermal emission …
High-velocity streams of dust originating from Saturn
Grün, Eberhard; Kempf, Sascha; Srama, Ralf +5 more
High-velocity submicrometre-sized dust particles expelled from the jovian system have been identified by dust detectors on board several spacecraft. On the basis of periodicities in the dust impact rate, Jupiter's moon Io was found to be the dominant source of the streams. The grains become positively charged within the plasma environment of Jupit…
Evidence for radio-source heating of groups
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M.
We report evidence that the gas properties of X-ray groups containing radio galaxies differ from those of radio-quiet groups. For a well-studied sample of ROSAT-observed groups, we found that more than half of the elliptical-dominated groups can be considered `radio-loud', and that radio-loud groups are likely to be hotter at a given X-ray luminos…
The Local Helioseismology of Inclined Magnetic Fields and the Showerglass Effect
Braun, D. C.; Cally, P. S.; Lindsey, C. +1 more
We present evidence for the dependence of helioseismic Doppler signatures in active regions on the line-of-sight angle in inclined magnetic fields. Using data from the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory, we performed phase-sensitive holography in the penumbrae of sunspots over the course of several days …
On the Nature of Coronal EIT Waves
Erdélyi, R.; Ballai, I.; Pintér, B.
Large-scale eruption events in the solar atmosphere can generate global waves, i.e., waves that propagate over distances comparable to the solar radius. In the low solar corona, global waves observed by SOHO EIT, generated by coronal mass ejections or flares, are usually referred to as ``EIT waves.'' The nature of these global waves is the subject…