Search Publications
Thomson Thick X-Ray Absorption in a Broad Absorption Line Quasar, PG 0946+301
Arav, N.; Elvis, M.; Peterson, B. M. +14 more
We present a deep ASCA observation of a broad absorption line quasar (BALQSO) PG 0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any other detector. If BALQSOs have intrinsic X-ray spectra similar to normal radio-quiet quasars, our observations imply that there is Thomson thick X-ray absorption (N…
Outflow velocity of interplume regions at the base of Polar Coronal Holes
Vial, J. -C.; Patsourakos, S.
We report on SUMER/SOHO observations at 1.05 Rsun of a well identified interplume region in a South Pole Coronal Hole. Combination of Doppler shifts and Doppler dimming measurements allowed to determine, for the first time, the total wind outflow velocity (~ 67 km s-1) at this height. Our calculations of the outflow velocity …
The evolution of 3CR radio galaxies from z1
McLure, R. J.; Dunlop, J. S.
We present the results of a comprehensive re-analysis of the images of a virtually complete sample of 28 powerful 3CR radio galaxies with redshifts 0.6<z<1.8 from the Hubble Space Telescope (HST) archive. Using a two-dimensional modelling technique we have derived scalelengths and absolute magnitudes for a total of 16 3CR galaxies with a med…
Strong spectral variability in NGC 7603 over 20 years
Dietrich, M.; Kollatschny, W.; Bischoff, K.
We present results of a long-term optical variability campaign on the Seyfert 1 galaxy NGC 7603 over a period of nearly 20 years. The optical continuum and the Balmer and Helium lines varied by a factor of 5 to 10 in this broad-line Seyfert 1 galaxy. Furthermore, it is remarkable that the optical FeII line blends varied with the same amplitude as …
Radial variation of solar wind electrons inside a magnetic cloud observed at 1 and 5 AU
Balogh, A.; Reisenfeld, D. B.; McComas, D. J. +5 more
The fortuitous observations of a magnetic cloud during the ACE/Ulysses radial alignment in March 1998 provide one of the first opportunities to study the same magnetic cloud at two different radial distances. In this paper, we use data from both ACE and Ulysses to examine the expansion of the cloud as well as of the adjacent noncloud solar wind. I…
Discovery of a Disk-collimated Bipolar Outflow in the Proto-Planetary Nebula IRAS 17106-3046
Kwok, Sun; Hrivnak, Bruce J.; Su, Kate Y. L.
We report the discovery of a collimated bipolar outflow emerging from a visible disk around the proto-planetary nebula IRAS 17106-3046. The radius of the disk, estimated to be 2500 AU at a distance of 4 kpc, is too large for it to be a Keplerian disk created by accretion. The radial intensity profile of the disk suggests that it is consistent with…
The visual double stars observed by the Hipparcos satellite
Nys, O.; Dommanget, J.
This paper is the introduction to the complete and correct list of all systems or individual components known in July 1997 which were observed by the Hipparcos satellite. The list concerns 18644 double or multiple systems and may be found at the CDS under reference I-260. Its format is the same as that used in the CCDM catalogue (Dommanget & N…
Rapidly oscillating M giant stars?
Koen, Chris; Laney, Dave
The Hipparcos mission discovered a few dozen M giant stars with periods P shorter than 10d. Similar stars may be found in other large data bases of new variables (e.g., OGLE). The three possible sources of the magnitude variations - pulsation, starspots and ellipsoidal deformation - are discussed in general terms. The parallaxes and V-I colour ind…
Abundance in the planetary nebulae NGC 6537 and He2-111
Pottasch, S. R.; Beintema, D. A.; Feibelman, W. A.
The ISO and IUE spectra of the bipolar planetary nebulae NGC 6537 and He2-111 are presented. These spectra are combined with the spectrum in the visual wavelength region from the nebulae to obtain a complete spectrum that is corrected for extinction. The chemical abundance of the nebulae is then determined and compared to previous determinations. …
Face-on Dust Disks in Galaxies with Optical Jets
Baum, Stefi A.; Sparks, William B.; Macchetto, F. Duccio +2 more
The presence of optical synchrotron jets in radio galaxies is relatively rare. Here we show that of the nearest five FR I 3CR radio galaxies showing optical jets, four show evidence for almost circular, presumably face-on, dust disks. This is strong support for the twofold idea that (1) jets emerge close to perpendicular to inner gas disks and (2)…