Search Publications
X-ray properties of active galactic nuclei with optical FeII emission.
Wang, T.; Brinkmann, W.; Bergeron, J.
ROSAT spectra of 86 Active Galactic Nuclei (AGN) with a broad range of optical FeII strengths have been analyzed. The results of the spectral analysis have been combined with optical and radio data as well as with optical emission line properties collected from the literature to understand the origin of the strong FeII emission and the nature of t…
An ISO SWS view of interstellar ices: first results.
Prusti, T.; de Graauw, T.; van Dishoeck, E. F. +7 more
The availability of SWS data from the Infrared Space Observatory is a landmark in the study of interstellar ices. This paper presents a brief review of what was known prior to the launch of ISO, and attempts a synthesis of what has been learned from the ISO observations available to date. Key areas of uncertainty are identified to provide a basis …
SWS spectroscopy of small grain features across the M17-Southwest photodissociation front.
Falgarone, E.; Wright, C. M.; Drapatz, S. +3 more
We present SWS spectra taken across the M17-Southwest photodissociation front and discuss spectral properties of PAHs and VSGs. We report new features at 4.65, 6.35, 8.7 and 11µm which we interpret as PAHs and/or VSGs emission. From feature intensity ratios along the cut, we find PAHs are mainly ionized and almost fully hydrogenated.
Spectrophotometry of UIR bands in the diffuse emission of the galactic disk.
Lemke, D.; Laureijs, R. J.; Lehtinen, K. +5 more
The spectrum of the unidentified infrared (UIR) emission bands between 5.8 and 11.6µm has been observed for the first time for the diffuse emission of the galactic disk where the interstellar radiation field (ISRF) is quite low. The UIR bands at 6.2, 7.7, 8.6, and 11.3µm have absolute intensities which are ~1/10th of the values observe…
Evidence for two classes of comets from their polarimetric properties at large phase angles.
Levasseur-Regourd, A. C.; Hadamcik, E.; Renard, J. B.
The dependence of the linear polarization of solar light scattered by cometary dust upon the phase angle has been studied, through appropriate fits, from a data base of 22 comets and 750 points (mainly in the green and red spectral domains). Although the whole coma polarization is found to slightly increase with the wavelength, all the data obtain…
Infrared spectrophotometry of M 17 with ISOCAM.
Palazzi, E.; Perault, M.; Abergel, A. +4 more
We report spectrophotometric observations of the HII region/neutral medium interface in M 17 obtained with the ISOCAM Circular Variable Filter (CVF) in the spectral range 5.15 to 16.5µm. The lines of singly-ionized species come mainly from the clumpy "neutral" interface, while the HII region dominates the line emission by higher-ionization s…
SWS observations of solid CO_2_ in molecular clouds.
Lutz, D.; Heras, A. M.; Prusti, T. +29 more
We report absorption features of solid CO_2_ stretching and bending modes in several lines of sight, including embedded young stellar objects and the Galactic Center source Sgr A*. The overall CO_2_ abundance in ices is ~15% relative to H_2_O. Profile shapes are consistent with the presence of grain mantles with distinct polar (H_2_O-rich) and non…
2.5-45µm SWS spectroscopy of the Circinus Galaxy.
Lutz, D.; Genzel, R.; Sturm, E. +5 more
We present 2.5-45µm ISO SWS spectra of the Circinus galaxy which is one of the closest spirals containing both a visually obscured Seyfert nucleus and circumnuclear starburst activity. In addition to PAH features, H_2_ and low excitation ionic lines ([FeII], [NeII], [SIII]) from the starburst region its spectrum shows several prominent lines…
ULYSSES plasma parameters: latitudinal, radial, and temporal variations.
Goldstein, B. E.; Neugebauer, M.; Phillips, J. L. +6 more
Observations by the Ulysses SWOOPS plasma experiment are used to investigate spatial and temporal gradients during the mission, with emphasis on more recent high latitude observations including the recent South Pole to North Pole passage during solar minimum. Compared to lower latitudes, the high latitude solar wind had higher average speed, proto…
Calibration and performance of the ISO Long-Wavelength Spectrometer.
Omont, A.; Ade, P. A. R.; Liseau, R. +52 more
The wavelength and flux calibration, and the in-orbit performance of the Infrared Space Observatory Long-Wavelength Spectrometer (LWS) are described. The LWS calibration is mostly complete and the instrument's performance in orbit is largely as expected before launch. The effects of ionising radiation on the detectors, and the techniques used to m…