Search Publications
The circumstellar environment of IRAS 16293-2422. ISO-LWS and SCUBA observations
Griffin, M.; Saraceno, P.; Correia, J. C.
We present far-infrared (FIR) continuum observations of the deeply embedded source IRAS 16293-2422 performed with the Long Wavelength Spectrometer (LWS) on-board the Infrared Space Observatory (ISO). We also report 450 and 850 µm mapping observations done with the Submillimetre Common-User Bolometer Array (SCUBA) at the James Clerk Maxwell T…
XMM-Newton study of the very young stellar cluster IC 348
Preibisch, T.; Zinnecker, H.
We analyze a XMM-Newton X-ray imaging observation of the very young stellar cluster IC 348 with an observing time of 12 h and a corresponding total (all detector) MOS-equivalent exposure time of 207 ks. Our observation is strongly affected by a very intense solar particle flare, due to which only the first half of the exposure time can be used for…
Two long-period X-ray pulsars detected in the SMC field around XTE J0055-727
Pietsch, W.; Haberl, F.; Schartel, N. +2 more
An XMM-Newton target of opportunity observation of the field around the transient 18.37 s pulsar
On comparing estimates of low-l solar p-mode frequencies from Sun-as-a-star and resolved observations
Chaplin, W. J.; Elsworth, Y.; Appourchaux, T. +3 more
Low-angular-degree (low-l) solar p modes provide a sensitive probe of the radiative interior and core of the Sun. Estimates of their centroid frequencies can be used to constrain the spherically symmetric structure of these deep-lying layers. The required data can be extracted from two types of observation: one where the modes are detected in inte…
Spatially resolved X-ray emission of EQ Pegasi
Schmitt, J. H. M. M.; Ness, J. -U.; Robrade, J.
We present an analysis of an XMM-Newton observation of the M dwarf binary EQ Pegasi with a special focus on the spatial structure of the X-ray emission and the analysis of light curves. Making use of data obtained with EPIC (European Photon Imaging Camera) we were for the first time able to spatially resolve the two components in X-rays and to stu…
Systematic astrometric observations of Proteus
Andrei, A. H.; Veiga, C. H.; Descamps, P. +2 more
Earth based observations of Proteus are made highly difficult by the magnitude difference with Neptune, and the closeness to the planet. To overcome these difficulties, observation campaigns using a Hg-mask coronograph developed for astrometry are being pursued at the Laboratório Nacional de Astrofísica, Brazil. The observations are made at visibl…
NGC 5385, NGC 2664 and Collinder 21: Three candidate open cluster remnants
Villanova, S.; Carraro, G.; de la Fuente Marcos, R. +1 more
We present CCD UBVI photometric and medium/high resolution spectroscopic observations obtained in the field of the previously unstudied dissolving open cluster candidates NGC 5385, NGC 2664 and Collinder 21. Our analysis is based on the discussion of star counts, photometry, radial velocity distribution, and proper motions available from the Tycho…
Solar latitudinal distortions: From observations to theory
Lefebvre, S.; Rozelot, J. P.
Solar diameters have been measured from different ground-based instruments on different sites all around the world. There are values dating back to three centuries ago, but the revival of interest began in the 1970s when it was claimed that a temporal periodic modulation had been found. The interest of such measurements, pinpointed from only two d…
Soft X-ray heating of the solar chromosphere during the gradual phase of two solar flares
Heinzel, P.; Berlicki, A.
In this paper we perform an analysis of the energetics of the solar flaring chromosphere irradiated by soft X-rays (SXR) emitted from overlying hot flare loops. To study an expected SXR heating we used the observations of two solar flares obtained with the Multichannel Subtractive Double Pass (MSDP) spectrograph attached to the Large Coronagraph o…
Is the giant elliptical galaxy NGC 5018 a post-merger remnant?
Bressan, A.; Buson, L. M.; Burstein, D. +2 more
NGC 5018, one of the weakest UV emitters among giant ellipticals (gE) observed with IUE, appears to consist of an optical stellar population very similar to that of the compact, dwarf elliptical M 32, which is several magnitudes fainter in luminosity than NGC 5018 and whose stellar population is known to be ∼3 Gyr old. Here we show that the mid-UV…