Search Publications
The phase curve of cometary dust: Observations of comet 96P/Machholz 1 at large phase angle with the SOHO LASCO C3 coronagraph
Schwenn, R.; Jockers, K.; Grynko, Ye.
We have analyzed brightness and polarization data of comet 96P/Machholz, obtained with the SOHO-LASCO C3 coronagraph at phase angles up to 167° and 157°, respectively. The polarization data are characteristic of a typical dusty comet. Within error limits the corresponding trigonometric fit describes the new data measured at l…
CDS wide slit time-series of EUV coronal bright points
Foley, C. R.; Doyle, J. G.; Nakariakov, V. M. +1 more
Wide slit (90''×240'') movies of four Extreme Ultraviolet coronal bright points (BPs) obtained with the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SoHO) have been inspected. The wavelet analysis of the He I 584.34 Å, O V 629.73 Å and Mg VII/IX 368 Å time-series confirms the oscillat…
GIRAFFE multiple integral field units at VLT: A unique tool to recover velocity fields of distant galaxies
Flores, H.; Hammer, F.; Puech, M. +2 more
The GIRAFFE spectrograph is unique in providing the integral field spectroscopy of fifteen distant galaxies at the same time. It has been successfully implemented at the second VLT unit within the FLAMES facility. We present GIRAFFE observations acquired during the Guaranteed Time Observation of the Paris Observatory, using total exposure times ra…
Shock wave driven by an expanding system of loops
Solanki, S. K.; Mierla, M.; Inhester, B. +5 more
We report on a Coronal Mass Ejection (CME) observed on June 27, 1999 by the UltraViolet Coronagraph Spectrometer (UVCS) telescope operating on board the SOHO spacecraft. The CME was also observed by the Large Angle Spectroscopic Coronagraph (LASCO). Emission of hot material has been recorded by UVCS propagating in front of an opening system of loo…
Time-resolved photometry and spectroscopy of the new deeply-eclipsing SW Sextantis star HS 0728+6738
Gänsicke, B. T.; Hagen, H. -J.; Engels, D. +2 more
We present time-resolved optical spectroscopy and photometry, and far-ultraviolet spectroscopy of
X-ray spectroscopy of the W UMa-type binary 44 Bootis
Gondoin, P.
44 Boo B, a W UMa-type binary system, was observed in June 2001 during one entire revolution period with the XMM-Newton observatory. The count rate in the 0.3 to 2 keV band is constant in average with 5 to 20% count rate increases reminiscent of flares. Spectral fitting of the EPIC spectra indicates a corona configuration with little contribution …
XMM-Newton observations of the two X-ray weak quasars PG 1411+442 and Mrk 304
Papadakis, I. E.; Brinkmann, W.; Ferrero, E.
We present the results of XMM-Newton observations of two X-ray weak quasars, PG 1411+442 and Mrk 304. In both cases the spectra can basically be represented by hard power laws with photon indices typical for radio-quiet quasars, heavily intrinsically absorbed by column densities of ∼2×1023 cm-2 in PG 1411+442 and ∼4×1022…
Statistical comparison of transition region blinkers and explosive events
Peter, H.; Brković, A.
Explosive events and blinkers are two observational classes of transients seen on the quiet Sun and an investigation of the significance of and relationship between such events may be critical for understanding basic processes at work in the solar atmosphere. We analysed five time-series spectra of the quiet Sun of transition region O XV 629 Å, O …
XMM-Newton observations of the giant H II region N 11 in the LMC
Gosset, E.; Nazé, Y.; Chu, Y. -H. +3 more
Using the sensitive XMM-Newton observatory, we have observed the giant H II region N 11 in the LMC for ∼30 ks. We have detected several large areas of soft diffuse X-ray emission along with 37 point sources. One of the most interesting results is the possible association of a faint X-ray source with BSDL 188, a small extended object of uncertain n…
Relating magnetic field strengths to hard X-ray emission in solar flares
van Driel-Gesztelyi, L.; Harra, L. K.; Matthews, S. A. +1 more
The observation of hard X-ray (HXR) emission in solar flares provides important diagnostic information about the acceleration and subsequent transport of energetic electrons in the flare process. However, while hard X-rays are thought to be emitted from the flare footpoints through thick-target bremsstrahlung interactions, the details of the trans…