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X-ray emission from NGC 1808: more than a complex starburst
Mas-Hesse, J. M.; Guainazzi, M.; Santos-Lleó, M. +5 more
Earlier observations of NGC 1808 in various wavebands (X-ray, optical, near-infrared, radio) provided evidence for the existence of either a starburst or a Seyfert 2 nucleus. We here present the results of multiwavelength XMM-Newton and Chandra observations, which directly prove the co-existence of thermal diffuse plasma and non-nuclear unresolved…
The extended hard X-ray emission from the Vela Plerion
Cusumano, G.; Bocchino, F.; Mineo, T. +2 more
We present the results of a broad band (3-200 keV) spectral analysis of BeppoSAX and XMM-Newton observations of the Vela plerion. The hard X-ray (>15 keV) emission is found to be extended over a region of 12'-15' radius, corresponding to a size of about 1.0-1.3 pc for a source distance of 290 pc. A single power law does not give an acceptable f…
The star cluster population of NGC 5253
Sauvage, M.; Cresci, G.; Vanzi, L.
We present a detailed analysis of the star cluster population in the starburst galaxy NGC 5253. Our work is based on HST optical and VLT Ks images. We detect more than 300 clusters, and for all of them we derive the photometry in the V, I and Ks bands and built a color-color V-I/V-Ks diagram. After correction for star contamination, we matched 115…
Are radio galaxies and quiescent galaxies different? Results from the analysis of HST brightness profiles
Capetti, A.; Morganti, R.; de Ruiter, H. R. +3 more
We present a study of the optical brightness profiles of early type galaxies, using a number of samples of radio galaxies and optically selected elliptical galaxies. For the radio galaxy samples - B2 of Fanaroff-Riley type I and 3C of Fanaroff-Riley type II - we determined a number of parameters that describe a "Nuker-law" profile, which were comp…
Coronal properties of G-type stars in different evolutionary phases
Pallavicini, R.; Peres, G.; Maggio, A. +1 more
We report on the analysis of XMM-Newton observations of three G-type stars in very different evolutionary phases: the weak-lined T Tauri star
The element abundance FIP effect in the quiet Sun
Young, P. R.
The Mg/Ne abundance ratio in the quiet Sun is measured in both network and supergranule cell centre regions through EUV spectra from the Coronal Diagnostic Spectrometer on SOHO. Twenty four sets of data over the period 1996 March to 1998 June (corresponding to solar minimum and the onset of the next cycle) are studied. Emission lines of the sequen…
The HST view of the nuclear emission line region in low luminosity radio-galaxies
Capetti, A.; Chiaberge, M.; Verdoes Kleijn, G.
We study the properties of the emission line regions in two samples of low luminosity radio-galaxies, while focusing on the Compact Emission Line Region (CELR) revealed to be a characteristic feature of these objects by HST narrow-band imaging. We find a strong correlation between line and optical continuum nuclear emission, which suggests that th…
High spatial resolution mid-infrared spectroscopy of NGC 5253: The stellar content of the embedded super-star cluster
Schaerer, D.; Sauvage, M.; Martín-Hernández, N. L.
We present the N-band (8-13 µm) spectrum of the hidden compact radio super-star cluster in NGC 5253, C2, obtained with TIMMI2 on the ESO 3.6 m telescope. The spectrum is characterised by a rising continuum due to warm dust, a silicate absorption and a strong [S IV] line at 10.5 µm. Weaker lines of [Ar II]I at 9.0 µm and [Ne II] a…
Observational evidence of the primary role played by photospheric motions in magnetic helicity transport before a filament eruption
Romano, P.; Contarino, L.; Zuccarello, F.
Many filament eruptions can be suitably described in the framework of the kink instability model, although it is not always easy to discriminate whether the helical flux rope writhes due to new emerging flux or to photospheric horizontal motions. In this paper we provide observational evidence of the important role which can be played by horizonta…
Flows in the solar atmosphere due to the eruptions on the 15th July, 2002
Mandrini, C. H.; van Driel-Gesztelyi, L.; Culhane, J. L. +4 more
Which kind of flows are present during flares? Are they compatible with the present understanding of energy release and which model best describes the observations? We analyze successive flare events in order to answer these questions. The flares were observed in the magnetically complex NOAA active region (AR) 10030 on 15 July 2002. One of them i…