Search Publications
Multi-wavelength study of X-ray luminous clusters at z ~ 0.3. I. Star-formation activity of cluster galaxies
Böhringer, H.; Biviano, A.; Pierini, D. +1 more
Context: The current paradigm of cosmic formation and evolution of galaxy clusters foresees growth mostly through merging. Galaxies in the infall region or in the core of a cluster undergo transformations owing to different environmental stresses.
Aims: For two X-ray luminous clusters at redshift z 0.3 with opposite X-ray morphologies (i.e., d…
The circumstellar disc in the Bok globule CB 26. Multi-wavelength observations and modelling of the dust disc and envelope
Pinte, C.; Ménard, F.; Duchêne, G. +10 more
Context: Circumstellar discs are expected to be the nursery of planets. Grain growth within such discs is the first step in the planet formation process. The Bok globule CB 26 harbours such a young disc.
Aims: We present a detailed model of the edge-on circumstellar disc and its envelope in the Bok globule CB 26.
Methods: The model is base…
STEREO/SECCHI Observations on 8 December 2007: Evidence Against the Wave Hypothesis of the EIT Wave Origin
Zhukov, A. N.; Rodriguez, L.; de Patoul, J.
The physical nature of EIT waves, large-scale bright fronts propagating in the solar corona, remains a subject of a continuing debate. Two main ways of interpreting this phenomenon have been suggested. One of them describes an EIT wave as a fast mode magnetosonic wave freely propagating in the corona. The other interpretation does not consider an …
Suzaku X-Ray Imaging and Spectroscopy of Cassiopeia A
Maeda, Yoshitomo; Ishida, Manabu; Petre, Robert +26 more
Suzaku X-ray observations of a young supernova remnant, Cassiopeia A, were carried out. K-shell transition lines from highly ionized ions of various elements were detected, including Chromium (Cr-Kα at 5.61 keV). The X-ray continuum spectra were modeled in the 3.4-40 keV band, summed over the entire remnant, and were fitted with a simplest combina…
The solar chromosphere at high resolution with IBIS. III. Comparison of Ca II K and Ca II 854.2 nm imaging
Cauzzi, G.; Uitenbroek, H.; Reardon, K. P.
Aims: Filtergrams obtained in Ca II H, Ca II K, and Hα are often employed as diagnostics of the solar chromosphere. The vastly disparate appearance between the typical filtergrams in these different lines calls into question the nature of what is actually being observed. We investigate the lack of obvious structures of magnetic origin such as fibr…
Martian oxygen density at the exobase deduced from O I 130.4-nm observations by Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars on Mars Express
Leblanc, F.; Bertaux, J. L.; Quémerais, E. +1 more
Several observations of the O I 130.4-nm triplet have been analyzed to determine the oxygen density in the Martian upper atmosphere using a three-dimensional Monte Carlo radiative transfer model describing each line of the triplet. Solar resonant scattering is the dominant source of excitation of the O I 130.4-nm triplet in the upper atmosphere of…
An equatorial periglacial landscape on Mars
Balme, M. R.; Gallagher, C.
We present evidence, drawn from new 25 cm/pixel "HiRISE" images of Mars, of landforms indicative of geologically-recent thaw degradation of ice-rich terrain near the Martian equator. We have focused our study on the head-region of Athabasca Vallis, a catastrophic flood-carved outflow channel thought to have been active within the last 2-8 Ma. The …
Preliminary characterization of the upper haze by SPICAV/SOIR solar occultation in UV to mid-IR onboard Venus Express
Vandaele, A. C.; Montmessin, F.; Fedorova, A. +6 more
The Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus/Solar Occultation at Infrared (SPICAV/SOIR) suite of instruments onboard the Venus Express spacecraft comprises three spectrometers covering a wavelength range from ultraviolet to midinfrared and an altitude range from 70 to >100 km. However, it is only recently (m…
Hubble Space Telescope Survey of Interstellar High-velocity Si III
Shull, J. Michael; Giroux, Mark L.; Collins, Joseph A.
We describe an ultraviolet spectroscopic survey of interstellar high-velocity cloud (HVC) absorption in the strong λ1206.500 line of Si III using the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. Because the Si III line is 4-5 times stronger than O VI λ1031.926, it provides a sensitive probe of ionized gas down to column …
Interpretation of Solar Magnetic Field Strength Observations
Ulrich, R. K.; Bertello, L.; Boyden, J. E. +1 more
This study based on longitudinal Zeeman effect magnetograms and spectral line scans investigates the dependence of solar surface magnetic fields on the spectral line used and the way the line is sampled to estimate the magnetic flux emerging above the solar atmosphere and penetrating to the corona from magnetograms of the Mt. Wilson 150-foot tower…