Search Publications
Properties of the nuclei of Centaurs Chiron and Chariklo
Jorda, L.; Lamy, P.; Groussin, O.
We analyze visible, infrared, radio and spectroscopic observations of 2060 Chiron in a synthetic way to determine the physical properties of its nucleus. From visible observations performed from 1969 to 2001, we determine an absolute V magnitude for the nucleus of 7.28±0.08 with an amplitude of 0.16±0.03, implying a nearly spherical nucleus with a…
The ISOPHOT - MAMBO survey of 3CR radio sources: Further evidence for the unified schemes
Meisenheimer, K.; Siebenmorgen, R.; Krause, O. +9 more
We present the complete set of ISOPHOT observations of 3CR radio galaxies and quasars, which are contained in the ISO Data Archive, providing 75 mid- and far-infrared spectral energy distributions (SEDs) between 5 and 200 µm. For 28 sources they are supplemented with MAMBO 1.2 mm observations and for 15 sources with new submillimetre data fr…
The XMM-NEWTON Ω project. I. The X-ray luminosity-temperature relation at z>0.4
Bartlett, J. G.; Giard, M.; Nichol, R. C. +9 more
We describe XMM-Newton Guaranteed Time observations of a sample of eight high redshift (0.45<z<0.62) clusters. The goal of these observations was to measure the luminosity and the temperature of the clusters to a precision of ∼10%, leading to constraints on the possible evolution of the luminosity-temperature (Lx-Tx) re…
Key parameters of W UMa-type contact binaries discovered by HIPPARCOS
Selam, S. O.
A sample of W UMa-type binaries which were discovered by the HIPPARCOS satellite was constructed with the aid of well defined selection criteria described in this work. The selection process showed up that several systems of which the variability types have been assigned as EB in HIPPARCOS catalogue are genuine contact binaries of W UMa-type. The …
Rings in the haloes of planetary nebulae
Corradi, R. L. M.; Sánchez-Blázquez, P.; Mellema, G. +2 more
We present a search for rings or arcs in the haloes of planetary nebulae (PNe). We discovered such structures in eight PNe, tripling the sample of PNe with known rings. This shows that, contrary to what was believed to date, the occurrence of mass loss fluctuations with timescales of 102-103 yrs at the end of the asymptotic g…
Two-dimensional spectroscopy of a sunspot. I. Properties of the penumbral fine structure
Bellot Rubio, L. R.; Schlichenmaier, R.; Tritschler, A. +3 more
We investigate the properties of the fine structure of a sunspot penumbra based on spectroscopic measurements with high spectral (λ/δλ=250 000) and high spatial (≈0.5 arcsec) resolution. The magnetically insensitive Fe I 557.6 nm line is used to probe the penumbral atmosphere. The data was taken at the German Vacuum Tower Telescope with the 2D-spe…
Far Infrared mapping of NGC 891
Tuffs, R. J.; Kylafis, N. D.; Madore, B. F. +1 more
We present deep maps of dust emission from the edge-on spiral galaxy NGC 891, obtained with the ISOPHOT instrument on board the Infrared Space Observatory in broad band filters with reference wavelengths centered on 170 and 200 µm. Using new processing methods to remove the effects of detector transients from the data, we detect cold dust at…
Observing Mkn 421 with XMM-Newton: The EPIC-PN point of view
Tagliaferri, G.; Ghisellini, G.; Tavecchio, F. +1 more
We present three observations (four exposures) of Mkn 421 performed by XMM-Newton in November and December 2002, concentrating on the EPIC-PN camera data. The X-ray spectra were soft and steepened toward high energies. The source was highly variable and the hardness ratio plots displayed a clear harder-when-stronger correlation. During two complet…
Mid-infrared spectral evidence for a luminous dust enshrouded source in Arp 220
Lutz, D.; Siebenmorgen, R.; Tielens, A. G. G. M. +3 more
We have re-analyzed the 6-12 µm ISO spectrum of the ultra-luminous infrared galaxy Arp 220 with the conclusion that it is not consistent with that of a scaled up version of a typical starburst. Instead, both template fitting with spectra of the galaxies NGC 4418 and M 83 and with dust models suggest that it is best represented by combination…
XMM-Newton survey of the Local Group galaxy M 33
Pietsch, W.; Haberl, F.; Hatzidimitriou, D. +3 more
In an XMM-Newton raster observation of the bright Local Group spiral galaxy