Search Publications
Multi-component absorption lines in the HST spectra of α Scorpii B
Reimers, D.; Baade, R.
Context: Extended atmospheres of late-type supergiants are of special interest with regard to the mass-loss process, the circumstellar physico-chemistry, and the evolution of stars.
Aims: The circumstellar envelope of α Sco A (M1.5 Iab) has been subject of intensive studies. Nevertheless the mechanism that is responsible for the mass outflow i…
The baryon density at z = 0.9-1.9. Tracing the warm-hot intergalactic medium with broad Lyman α absorption
Reimers, D.; Janknecht, E.; Prause, N. +1 more
Aims:We present an analysis of the Lyman α forests of five quasar spectra in the near UV. Properties of the intergalactic medium (IGM) at an intermediate redshift interval (0.9≤ z≤1.9) are studied. The amount of baryons in the diffuse photoionised IGM and the warm-hot intergalactic medium (WHIM) are traced to get constraints on the redshift evolut…
XMM-Newton observations of the Small Magellanic Cloud: the 280 s Be/X-ray binary pulsar AX J0058-7203 in outburst
Pietsch, W.; Haberl, F.
Context: The Be/X-ray binary pulsar AX J0058-720, discovered by ASCA, was in the field of view of the EPIC instruments during five XMM-Newton observations in the direction of the Small Magellanic Cloud (SMC).
Aims: We used the EPIC data of the X-ray pulsar in order to investigate its long-term temporal and spectral behaviour between 2000 and 2…
Discovery of inward moving magnetic enhancements in sunspot penumbrae
Woch, J.; Solanki, S. K.; Zhang, J.
Context: Sunspot penumbrae show a fine structure in continuum intensity which displays considerable dynamics. The magnetic field, in contrast, although also highly structured, has been shown to be relatively static in earlier studies.
Aims: We report on the discovery of inward moving magnetic enhancements in the penumbrae of two regular sunspo…
A multi-wavelength study of the IRAS Deep Survey galaxy sample. II. The far-IR properties
Mazzei, P.; Bettoni, D.; Della Valle, A.
Context: The luminosity function (LF) is a basic tool in the study of galaxy evolution since it constrains galaxy formation models. The earliest LF estimates in the IR and far-IR spectral ranges seem to suggest strong evolution. Deeper samples are needed to confirm these predictions. We have a useful IR data set, which provides a direct link betwe…
Combined astrometric catalogue EOC-3. An improved reference frame for long-term Earth rotation studies
Vondrák, J.; Štefka, V.
Context: In the past, we collected the astrometric observations of latitude/universal time variations made worldwide at 33 observatories. These observations, re-analyzed with the Hipparcos Catalogue, were then used to determine the Earth Orientation Parameters (EOP) at 5-day intervals, covering the interval 1899.7-1992.0. Later on, new astrometric…
The surface brightness of the Galaxy at the solar neighbourhood
Gould, A.; Combes, F.; Melchior, A. -L.
We present a new determination of the surface brightness of our Galaxy at the Solar Neighbourhood as observed from outside the Galaxy. We rely on various existing optical and infra-red surveys to obtain a multiwavelength estimate. On the one hand, scattered light does not contribute significantly to the surface brightness. On the other hand, optic…
Kinematic segregation of nearby disk stars from the Hipparcos database
Teixeira, R.; de Souza, R. E.
Aims:To better understand our Galaxy, we investigate the pertinency of describing the system of nearby disk stars in terms of a two-component Schwarzschild velocity distribution.Using the proper motion and parallax information of Hipparcos database, we determine the parameters characterizing the local stellar velocity field of a sample of 22 000 d…
On understanding the meaning of l = 2 and 3 p-mode frequencies as measured by various helioseismic instruments
Chaplin, W. J.; Appourchaux, T.
Aims:Frequencies of the low-degree p-mode oscillations of the Sun may be extracted either from data collected by instruments that make full-disc observations of the Sun as a star, or from data collected by instruments that resolve, or image, the Sun's surface onto many detector elements. The two methods can show marked differences in their sensiti…
Application of a MHD hybrid solar wind model with latitudinal dependences to ULYSSES data at minimum
Aibéo, A.; Lima, J. J. G.; Sauty, C.
Aims:In a previous work, Ulysses data was analyzed to build a complete axisymmetric MHD solution for the solar wind at minimum including rotation and the initial flaring of the solar wind in the low corona. This model has some problems in reproducing the values of magnetic field at 1 AU despite the correct values of the velocity. Here, we intend t…