Search Publications
Discovery of a new INTEGRAL source: IGR J19140+0951
Rodriguez, J.; Henri, G.; Petrucci, P. O. +5 more
IGR J19140+0951 (formerly known as IGR J19140+098) was discovered with the INTEGRAL satellite in March 2003. We report the details of the discovery, using an improved position for the analysis. We have performed a simultaneous study of the 5-100 keV JEM-X and ISGRI spectra from which we can distinguish two different states. From the results of our…
Stellar activity and magnetism studied by optical interferometry
Jankov, S.; Kilbinger, M.; Lanz, T. +5 more
By means of numerical simulations, we investigate the ability of optical interferometry, via the fringe phase observable, to address stellar activity and magnetism. To derive abundance maps and stellar rotation axes, we use color differential interferometry which couples high angular resolution to high spectral resolution. To constrain magnetic fi…
Optical and infrared spectroscopic analysis of the post-AGB star candidate IRAS 19386+0155
Pereira, C. B.; Lorenz-Martins, S.; Machado, M.
This work reports high-resolution spectroscopic stellar parameters and abundance analysis of the post-AGB star IRAS 19386+0155. The analysis of the high resolution spectrum shows that it has an effective temperature of Teff=6800±100 K and a surface gravity of log g = 1.4±0.2. The abundance analysis reveals IRAS 19386+0155 to be a metal-…
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…