Search Publications
Comparison of SOHO UVCS and MLSO MK4 coronameter densities
Cho, K. -S.; Moon, Y. -J.; Choe, G. S. +3 more
We have compared the density distributions of solar corona obtained by SOHO Ultraviolet Coronagraph Spectrometer (UVCS) and Mauna Loa Solar Observatory (MLSO) MK4 coronameter. This is the first attempt to compare the coronal densities estimated by the two instruments. In the spectral data of UVCS, we have selected two emission lines (O VI 1032 Åan…
ADONIS high contrast infrared imaging of Sirius-B
Pantin, E.; Bonnet-Bidaud, J. M.
Context: Sirius is the brightest star in the sky and a strong source of diffuse light for modern telescopes so that the immediate surroundings of the star are still poorly known.
Aims: We study the close surroundings of the star (2 to 25´´) by means of adaptive optics and coronographic device in the near-infrared, using the ESO/ADONIS system. …
Spectral analysis of LMC X-2 with XMM/Newton: unveiling the emission process in the extragalactic Z-source
Robba, N. R.; Iaria, R.; di Salvo, T. +2 more
Aims:We present the results of the analysis of an archival observation of LMC X-2 performed with XMM/Newton. The spectra taken by high-precision instruments have never been analyzed before.
Methods: We find an X-ray position for the source that is inconsistent with the one obtained by ROSAT, but in agreement with the Einstein position and that…
UV optical measurements of the Nozomi spacecraft interpreted with a two-component LIC-flow model
Bzowski, M.; Yoshikawa, I.; Takahashi, Y. +7 more
Aims: Following recent reports on spectroscopic observations by SWAN/SOHO suggesting that the flows of neutral interstellar helium and hydrogen in the inner heliosphere are slightly divergent, we tried to verify them on the basis of simultaneous photometric observations of heliospheric hydrogen and helium glows performed by a spacecraft located on…
SAX J1712.6-3739: a persistent hard X-ray source as monitored with INTEGRAL
Fiocchi, M.; Ubertini, P.; Bazzano, A. +1 more
Context: The X-ray source SAX J1712.6-3739 is a very weak low mass X-ray binary discovered in 1999 with BeppoSAX and located in the Galactic Center. This region has been intensively investigated by the INTEGRAL satellite with an unprecedented exposure time, providing an unique opportunity to study the hard X-ray behavior also for weak objects.
NLTE modelling of the flaring atmosphere above sunspot
Heinzel, P.; Schmieder, B.; Li, H. +1 more
Aims: We performed an analysis of the solar flaring atmosphere above sunspots. During the flare on October 20, 2003 many flaring structures were observed projected onto the sunspots. We analysed the Hα and Ca II line profiles emitted by the ribbons partially overlapping the sunspots. In the penumbra, the line intensity in the far wings is lower th…
Distribution of coronal heating in a solar active region
Gontikakis, C.; Contopoulos, I.; Dara, H. C.
Aims: We investigate the distribution of heating of coronal loops in a non-flaring solar active region, using a simple electrodynamic model: the random displacements of the loop footpoints, caused by photospheric plasma motions, generate electric potential differences between the footpoints and, as a result, electric currents flow along the loops,…
Spectroscopic distances of 28 nearby star candidates
Stecklum, B.; Jahreiß, H.; Meusinger, H. +1 more
Aims: Twenty eight hitherto neglected candidates for the Catalogue of Nearby Stars (CNS) were investigated to verify their classification and to improve their distance estimates. All targets had at least a preliminary status of being nearby dwarf stars based on their large proper motions and relatively faint magnitudes. Better photometric and/or s…
Q2237+0305 in X-rays: spectra and variability with XMM-Newton
Vignali, C.; Palumbo, G. G. C.; Fedorova, E. V. +1 more
Aims: X-ray observations of gravitationally lensed quasars may allow us to probe the inner structure of the central engine of a quasar. Observations of Q2237+0305 (Einstein Cross) in X-rays may be used to constrain the inner structure of the X-ray emitting source.
Methods: Here we analyze the XMM-Newton observation of the quasar in the gravita…
Far-infrared spectroscopic observations of the Galactic center region
Nakagawa, T.; Okada, Y.; Spaans, M. +2 more
Context: The Galactic center region is luminous in the far-infrared (FIR), but dominant sources of this luminosity are still controversial.
Aims: We investigate physical conditions of the diffuse interstellar medium in the Galactic center region by multi-line spectroscopy in the FIR.
Methods: We analyze the archival data of the Galactic ce…