Search Publications
Properties of magnetic elements in the quiet Sun using the marker-controlled watershed method
Zhang, J.; Yang, S. H.; Xie, Z. X. +2 more
Context: The quiet Sun is an important part of understanding the global magnetic properties of the Sun. A recently launched observation system, named HINODE, provides a lot of high-resolution images for studying the quiet Sun. Obviously, it is time-consuming to analyze these images by hand. It is desirable to develop a technique for recognizing ma…
Observation of a solar energetic particle event behind previous coronal mass ejection
Laitinen, T.; Kocharov, L.; Al-Sawad, A. +1 more
On 2001 October 19-21 the Energetic and Relativistic Nuclei and Electron (ERNE) instrument on the Solar and Heliospheric Observatory (SOHO) observed two gradual solar energetic particle (SEP) events separated by 15 h, in association with two X1.6/2B solar flares and halo coronal mass ejections (CMEs). The observational data suggest that the second…
Space observations of B stars with CoRoT
Auvergne, M.; Deleuil, M.; Jorda, L. +20 more
We present the preliminary results of the exploration of pulsating B stars observed with the CoRoT space mission. The previously known group of Slowly Pulsating B stars gains a substantial amount of new candidates, offering the opportunity to test stellar models beyond individual cases. Besides these well-defined stars, the analysis of other B sta…
Effective area calibration of the reflection grating spectrometers of XMM-Newton. II. X-ray spectroscopy of DA white dwarfs
Kaastra, J. S.; Lanz, T.; Hubeny, I. +1 more
Context: White dwarf spectra have been widely used as a calibration source for X-ray and EUV instruments. The in-flight effective area calibration of the reflection grating spectrometers (RGS) of XMM-Newton depend upon the availability of reliable calibration sources.
Aims: We investigate how well these white dwarf spectra can be used as stand…
HF wave activity in the low and middle-altitude polar cusp
Pitout, F.; Reme, H.; Trotignon, J. -G. +3 more
We reported the results of our investigations of wave activity in high-frequency range performed on board CLUSTER spacecraft in the middle-altitude cusp region, around 5 RE during August and September 2002. Our analysis was mainly based on the registration gathered by the WHISPER instrument (Waves of HIgh frequency and Sounder for Probi…
Experimental data and analysis of the October 2003 Forbush decrease
D'Andrea, C.; Poirier, J.; Balsara, D. S.
On October 28, 2003 an Earthward-directed coronal mass ejection (CME) was observed from SOHO/LASCO imagery in conjunction with an X17 solar flare. The CME, traveling at nearly 2000 km/s, impacted the Earth on October 29, 2003 causing ground-based particle detectors to register a counting rate drop known as a Forbush decrease. The CME was not only …
The retrieval of altitude profiles of the Martian aerosol microphysical characteristics from the limb measurements of the Mars Express OMEGA spectrometer
Bibring, J. -P.; Vasilyev, A. V.; Mayorov, B. S.
Parameterization of the spectral dependence of the optical characteristics of Martian aerosols has been proposed for processing the results of measurements of outgoing radiation. A method for retrieving the altitude profiles of the microphysical characteristics of Martian aerosols from the limb spectrometry of the OMEGA instrument of the Mars Expr…
Revisiting the optical interferometry observations of HR 4049
Quirrenbach, A.; Lopez, B.; Chesneau, O. +4 more
Aims: We present high spatial resolution observations in the mid-infrared of the dusty core of the binary system HR 4049.
Methods: We used the mid-infrared interferometer MIDI/VLTI with 40 m projected baselines. These observations provided two spectrally dispersed visibility curves at a spatial resolution of ~10 mas. Acquisition images and spe…
The hard X-ray view of bright infrared galaxies
Walter, R.; Cabral, N.
Aims: The synthesis of the cosmic X-ray background (CXB) requires a large population of Compton-thick active galactic nuclei that have not been detected so far. We probe whether bright infrared galaxies could harbor a population of Compton-thick nuclei and if they could contribute significantly.
Methods: We analyzed 112 Ms of INTEGRAL observat…
Footpoint Motions as Evidence for Patchy Reconnections in an M9.1 Solar Flare
Wang, Lin
We present an investigation on the UV footpoint motions of an M9.1 two-ribbon solar flare that occurred on 2004 July 22, employing the TRACE 1700 Å images and a magnetogram observed by SOHO/MDI. In the beginning, we found that the UV footpoints spread a two-dimensional distribution in, especially, the negative magnetic region, rather than a quasi-…