Search Publications
The X-ray jet in the merging galaxy system Markarian 266
Kollatschny, W.; Kowatsch, P.
We present deep ROSAT X-ray images of the double nucleus galaxy Mrk 266 in combination with optical images and spectra. The High Resolution Imager (HRI) X-ray morphology can be divided into four components: two nuclei of the merging galaxies, a diffuse galactic component and a strong northern jet coincident with very strong optical line emission. …
High latitude ULYSSES observations of CIR accelerated ions and electrons
Simnett, G. M.; Sayle, K. A.
From the comparison of the intensity maxima of ~ 1 MeV/nuc. ions with those of the 40-65 keV electrons and higher energy ions ( ~ 2-4 and 4-8 MeV/nuc.), during Ulysses' ascent to the solar south pole, 1992-1994, evidence has been found for the ~ 1 MeV/nuc. ions observed at high latitude by the Ulysses spacecraft to have originated at mid-latitudes…
Magnetic field models for A and B stars. V. The magnetic field and photometric variation of 84 Ursae Majoris
Manset, N.; Wade, G. A.; Bastien, P. +2 more
We present new longitudinal magnetic field and Stroemgren photometric measurements of the Bp star 84 UMa. From these data we determine a new rotational period Prot=1.38576 deg +/- 0.00080 deg, which is inconsistent with previously published values. The magnetic measurements indicate the presence of a weak, dominantly dipolar magnetic fi…
The space distribution of HIPPARCOS carbon stars
Bergeat, J.; Knapik, A.; Rutily, B.
More than 300 galactic carbon-rich stars have been observed by the HIPPARCOS satellite. Parallaxes and proper motions are given with an unprecedented accuracy. Carbon stars are however distant giants and there are only 4 stars with a parallax accuracy better than 20 % (26 stars if 30 %). Direct use of observed data is thus severely hampered by sta…
ISO observations of the radio-loud BALQSO 1556+3517
Clavel, J.
To date, the quasar 1556+3517 is the only radio loud Broad Absorption Line QSO (BALQSO; Becker et al. 1997). This prompted narrow band filter imaging observations in the range 4-15 mu with the ISO satellite. The source is clearly detected in all filters and appears point-like and isolated at the resolution of ISO. The overall Spectral Energy Distr…
A HgMn companion to the Cepheid SU Cyg.
Wahlgren, G. M.; Evans, N. R.
We report here the discovery of a chemically peculiar star of the HgMn type as a companion to the classical Cepheid variable SU Cyg. This is the first investigation of a HgMn star in a binary system in which a star of a more advanced evolutionary stage is the primary. The age of the Cepheid provides an estimate to the age of the chemical peculiari…
Search for cool circumstellar matter in the Ursae Majoris group with ISO
Henning, Thomas; Abraham, Peter; Lemke, Dietrich +2 more
We observed the mid- and far-infrared spectral energy distributions of 9 A-type stars from the 300 Myrs old Ursae Majoris group using the ISO satellite and the UKIRT telescope. We found that only 1 out of the 9 stars shows clear signature of circumstellar dust, and we derived an upper limit of 0.05 Mmoon for the dust mass around the oth…
Broad band X-ray spectrum of Cygnus X-1
Rao, A. R.; Chitnis, V. R.; Agrawal, P. C.
We present the hard X-ray (20 - 100 keV) observations of Cygnus X-1 obtained using a large area balloon-borne Xenon filled Multi-anode Proportional Counter (XMPC) telescope. The observations were carried out during the gamma_2 state of the source and we obtain a power law photon index of 1.62+/-0.07. To constrain the spectral shape of the source, …
The pulsating yellow supergiant V810 Centauri
Meynet, G.; Burki, G.; Burnet, M. +1 more
The F8 Ia supergiant
MG II h&k line diagnostics of IM Pegasi
Houdebine, E. R.; Dempsey, R. C.; Olah, K. +2 more
We have analysed the Mgii h&k resonance lines of IM Peg (KII-III) on 14 high resolution IUE LWR spectra and compared the results coming from visual spectroscopic and UBV(RI)_C photometric data. The `clean' spectra (free from interstellar absorption) were modelled using a convolution of the rotational profile with a Gaussian profile, that repre…