Search Publications
Tentative detection of warm intervening gas towards PKS 0548-322 with XMM-Newton
Sako, M.; Barcons, X.; Carrera, F. J. +2 more
We present the results of a long (~93 ks) XMM-Newton observation of the bright BL-Lac object PKS 0548-322 (z= 0.069). Our Reflection Grating Spectrometer (RGS) spectrum shows a single absorption feature at an observed wavelength λ= 23.33 +/- 0.01 Å, which we interpret as OVI Kα absorption at z= 0.058, i.e. ~3000 km s-1 from the backgrou…
Proper motion study of the ROSAT selected WTTS candidates around Taurus-Auriga
LI, J. Z.
Astrometric study of the T Tauri stars (TTS) candidates and non-TTS X-ray sources around Tau-Aur [Li, Hu 132 (1998) 173], based on the Hipparcos and the ACT Reference Catalogue, is presented in this paper. The ROSAT selected X-ray sources are found to have complicated nature. A few of them are associated with the Tau-Aur or the Orion Star Forming …
Drifting field-aligned density structures in the night-side polar cap
Gurnett, D. A.; Persoon, A. M.; Pickett, J. S. +5 more
Spatio-temporal properties of density irregularities in the night-side polar cap are inferred from multi-point observations of auroral hiss at a radial distance of 5 Earth radii. In this case study, we use high resolution data of the wave instruments onboard the four Cluster spacecraft to estimate the local plasma density, obtaining values close t…
Shading under Titan's sky
Grieger, B.
During the descent of the Huygens probe in January 2005, its Descent Imager/Spectral Radiometer (DISR) will take the first close up images of Titan's surface. The shading imposed by the illumination of a planetary surface contains information on its topography. For planetary bodies without an optically thick atmosphere, the light can be assumed to…
Interferometric identification of ion acoustic broadband waves in the auroral region: CLUSTER observations
André, M.; Vaivads, A.; Fazakerley, A. +2 more
We determine the phase velocity and k vector for parallel and oblique broadband extremely low frequency, ELF, waves on nightside auroral magnetic field lines at altitudes around 4.6 RE. We use internal burst mode data from the EFW electric field and wave instrument onboard the Cluster spacecraft to retrieve phase differences between the…
First observations of the planetary Fourier spectrometer at Mars
Piccioni, G.; Grassi, D.; Khatuntsev, I. +8 more
The first results of the Planetary Fourier Spectrometer (PFS) orbiting the planet Mars are reviewed and discussed here, with reference to a set of studies being published elsewhere. An average global spectrum ranging from 200 to 8200 cm -1 is discussed by comparing it to the ISO SWS Martian spectrum and to the global synthetic spectrum …
A phase locking mechanism for nongyrotropic electron distributions upstream of the Earth's bow shock
Glassmeier, K. -H.; Fazakerley, A. N.; Gurgiolo, C. +2 more
Observations of nongyrotropic electron distributions in the region upstream of the Earth's bow shock suggest that there exists a mechanism to lock in their phase, otherwise they would rapidly gyrophase mix into a ring-beam distribution. Measurements by the Plasma Electron and Current Experiment (PEACE) on the Cluster spacecraft have provided a way…
Study of the structure of abell 3571: An XMM-Newton view
Hudaverdi, M.; Furuzawa, A.; Yamashita, K.
The non-uniform temperature and abundance distribution in the central region of A3571 is investigated. Our previous analysis of ASCA data suggested that the cluster experiences a relatively large scale group infall. By the advantage of XMM-Newton's high angular resolution, we are able to investigate dynamical structures down to the 100 kpc scale. …
Non-thermal processes associated with rising structures and waves during a "halo" type CME
Karlický, M.; Aurass, H.; Pohjolainen, S. +2 more
We analyse structures and events connected with a flare-associated "halo" type coronal mass ejection (CME) observed on December 18, 2000. A GOES C7.0 class X-ray flare started at 11:02 UT in NOAA Active Region 9269, located at N14 E03. Yohkoh SXT observed slowly rising soft X-ray loops already some 5 min before flare start. Hα images show a two-ri…
Coronal oscillations in the vicinity of a sunspot as observed by GIS/CDS
Foley, C. R.; Doyle, J. G.; Banerjee, D. +2 more
In this paper, we present results from a time series analysis of data from the Grazing Incidence Spectrometer (GIS), onboard SoHO. Our observations were concentrated at the boundary between the quiet Sun and an active region, close to a sunspot plume. The dominant oscillations in all the lines studied are of periods longer than 5 min. Although our…