Search Publications
UVCS/SOHO observations of a CME-driven shock: Consequences on ion heating mechanisms behind a coronal shock
Raymond, J. C.; Wu, R.; Kohl, J. +3 more
We report the observation of a 1100 km s-1 CME-driven shock with the UltraViolet Coronagraph Spectrometer (UVCS) telescope operating on board SOHO on March 3, 2000. The shock speed was derived from the type II radio burst drift rate and from UVCS observations that can yield the density profile just before the passage of the shock. A CME…
Multi-wavelength study of the Seyfert 1 galaxy NGC 3783 with XMM-Newton
Kaastra, J. S.; Behar, E.; Sako, M. +5 more
We present the analysis of multi-wavelength XMM-Newton data from the Seyfert galaxy NGC 3783, including UV imaging, X-ray and UV lightcurves, the 0.2-10 keV X-ray continuum, the iron Kalpha emission line, and high-resolution spectroscopy and modelling of the soft X-ray warm absorber. The 0.2-10 keV spectral continuum can be well reproduced by a po…
Shock-excited radio burst from reconnection outflow jet?
Mann, G.; Vršnak, B.; Aurass, H.
Models of dynamic (two-ribbon-, arcade) flares involve the formation of a system of standing slow and possibly also fast mode shock waves associated with the fast reconnection process below the erupting filament. These shocks are anticipated theoretically, but are not unambiguously confirmed by observations. In this paper we identify for the first…
Hidden star-formation in the cluster of galaxies Abell 1689
Elbaz, D.; Cesarsky, C.; Duc, P. -A. +6 more
At a redshift of 0.18, Abell 1689 is so far the most distant cluster of galaxies for which substantial mid-infrared (MIR) data have been published. Its mapping with the ISOCAM camera onboard the ISO satellite allowed the detection of 30 cluster members at 6.75 micron (LW2 filter) and 16 cluster members at 15 micron (LW3 filter) within a clustercen…
The runaway black hole GRO J1655-40
Mirabel, I. F.; Combi, J. A.; Mignani, R. +3 more
We have used the Hubble Space Telescope to measure the motion in the sky and compute the galactocentric orbit of the black hole X-ray binary GRO J1655-40. The system moves with a runaway space velocity of 112+/- 18 km s-1 in a highly eccentric (e = 0.34+/- 0.05) orbit. The black hole was formed in the disk at a distance greater than 3 k…
Tidal dwarfs in the M81 group: The second generation?
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +8 more
We derive quantitative star formation histories of the four suspected tidal dwarf galaxies in the M 81 group, Holmberg IX, BK3N, Arp-loop (A0952+69), and Garland, using Hubble Space Telescope/Wide Field Planetary Camera 2 images in F606W and F814W obtained as part of a Snapshot survey of dwarf galaxies in the Local Universe. We consider the spatia…
HIPPARCOS age-metallicity relation of the solar neighbourhood disc stars
Arimoto, N.; Ibukiyama, A.
We derive age-metallicity relations (AMRs) and orbital parameters for the 1658 solar neighbourhood stars to which accurate distances are measured by the HIPPARCOS satellite. The sample stars comprise 1382 thin disc stars, 229 thick disc stars, and 47 halo stars according to their orbital parameters. We find a considerable scatter for thin disc AMR…
Combined VLT ISAAC/ISO SWS spectroscopy of two protostellar sources. The importance of minor solid state features
van Dishoeck, E. F.; Pontoppidan, K. M.; Dartois, E. +2 more
We discuss the L band infrared spectra of two massive protostars in the region of the so-called 3.47 mu m absorption feature. The high sensitivity VLT-ISAAC spectra of the two differently evolved massive protostars GL 989 and GL 2136, together with dedicated infrared laboratory experiments on ice molecular interactions, allow us to propose the ide…
Understanding the nature of FR II optical nuclei: A new diagnostic plane for radio galaxies
Capetti, A.; Chiaberge, M.; Celotti, A.
We extend our study of the nuclei of 3CR FR II radio galaxies through HST optical images up to z = 0.3. In the majority of them an unresolved nucleus (central compact core, CCC) is found. We analyze their position in the plane formed by the radio and optical nuclear luminosities in relation to their optical spectral properties. The broad-lined obj…
Oscillations above sunspots: Evidence for propagating waves?
O'Shea, E.; Muglach, K.; Fleck, B.
We present results of an analysis of time series data observed in sunspot umbral regions. The data were obtained in the context of the SOHO Joint Observing Program (JOP) 97 in September 2000. This JOP included the Coronal Diagnostic Spectrometer (CDS) and the Michelson Doppler Imaging (MDI) instrument, both part of SOHO, the TRACE satellite and va…