Search Publications
Phase-resolved X-ray and optical spectroscopy of the massive binary HD 93403
Gosset, E.; Rauw, G.; Vreux, J. -M. +4 more
We report the first results of a campaign aimed at the study of early-type binaries with the XMM-Newton observatory. Phase-resolved EPIC spectroscopy of the eccentric binary HD 93403 reveals a clear orbital modulation of the X-ray luminosity as a function of the orbital phase. Below 1.0 keV, the observed X-ray flux is modulated by the opacity of t…
Mid-infrared observations of the ultraluminous galaxies IRAS 14348-1447 , IRAS 19254-7245 , and IRAS 23128-5919
Le Floc'h, E.; Madden, S. C.; Sauvage, M. +6 more
We present a study of the three ultraluminous infrared galaxies IRAS 14348-1447, IRAS 19254-7245, and IRAS 23128-5919, based on mid-infrared (MIR) spectro-imaging (5-18 mu m) observations performed with ISOCAM. We find that the MIR emission from each system, which consists of a pair of interacting late type galaxies, is principally confined to the…
Extended mid-infrared emission from VV 114: Probing the birth of a ULIRG
Le Floc'h, E.; Cesarsky, C.; Sauvage, M. +5 more
We present our 5-16 mu m spectro-imaging observations of
Location of narrowband spikes in solar flares
Benz, A. O.; Vilmer, N.; Saint-Hilaire, P.
Narrowband spikes of the decimeter type have been identified in dynamic spectrograms of Phoenix-2 of ETH Zurich and located in position with the Nançay Radioheliograph at the same frequency. The spike positions have been compared with the location of hard X-ray emission and the thermal flare plasma in soft X-rays and EUV lines. The decimetric spik…
Inferences on the solar envelope with high-degree modes
Christensen-Dalsgaard, J.; Rabello-Soares, M. C.; Basu, S. +1 more
We investigate the structure of the Sun by helioseismic inversion of a set of p-mode frequencies which includes new precise observations of modes with high degree (l < 1000) obtained from the MDI instrument on the SOHO satellite (Rhodes et al. \cite{rh98}). Such data have the potential to improve the resolution of the solar structure in the nea…
Calibration of the distance scale from galactic Cepheids. II. Use of the HIPPARCOS calibration
Musella, I.; Paturel, G.; Theureau, G. +3 more
New estimates of the distances of 36 nearby galaxies is presented. These are based on the calibration of the V- and I-band Period-Luminosity relations for galactic Cepheids measured by the HIPPARCOS mission. The distance moduli are obtained in a classical way. The statistical bias due to the incompleteness of the sample is corrected according to t…
Infrared spectral classification of normal stars.
Heras, A. M.; Shipman, R. F.; Price, S. D. +8 more
Moderate resolution (~400) 2.38-45.2 mu m infrared spectra of stars without dust features were obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). The observations are part of a larger program with the objective to extend and refine the current infrared classification schemes. In particular, our dat…
Broad-band continuum and line emission of the gamma-ray blazar PKS 0537-441
Maraschi, L.; Pian, E.; Falomo, R. +10 more
PKS 0537-441, a bright gamma -ray emitting blazar, was observed at radio, optical, UV and X-ray frequencies during various EGRET pointings, often quasi-simultaneously. In 1995 the object was found in an intense emission state at all wavelengths. BeppoSAX observations made in 1998, non-simultaneously with exposures at other frequencies, allow us to…
Chandra LETGS observation of the active binary Algol
Schmitt, J. H. M. M.; Burwitz, V.; Mewe, R. +2 more
A high-resolution spectrum obtained with the low-energy transmission grating onboard the Chandra observatory is presented and analyzed. Our analysis indicates very hot plasma with temperatures up to T~ 15-20 MK from the continuum and from ratios of hydrogen-like and helium-like ions of Si, Mg, and Ne. In addition lower temperature material is pres…
Detection of HD in emission towards Sagittarius B2
Ceccarelli, C.; Caux, E.; Swinyard, B. M. +2 more
The giant molecular cloud Sagittarius B2, located near the Galactic Centre, has been observed in the far-infrared by the ISO Long Wavelength Spectrometer. Wavelengths in the range 47-196 mu m were covered with the high resolution Fabry-Pérot spectrometer, giving a spectral resolution of 30-40 km s-1. The J=1->0 and J=2->1 rotation…