Search Publications
The effect of rotation on the absolute visual magnitudes of OB stars measured with Hipparcos.
Kudritzki, R. P.; Hoogerwerf, R.; Lamers, H. J. G. L. M. +2 more
We derive the absolute visual magnitudes of 14 OB-stars of luminosity class III to V from the parallaxes measured by Hipparcos. The values of M_V_ can differ by as much as 1.5mag from the M_V_-spectral type calibration. Slowly rotating stars, vsini<100km/s, are significantly fainter in M_V_ than stars with vsini>100km/s of the same spectral …
MeV to GeV electron propagation and modulation: results of the KET-telescope onboard ULYSSES
Ferrando, P.
The KET instrument onboard Ulysses is continuously monitoring the flux of MeV to GeV electrons. I summarize here the main results obtained with data from the ~ 7 MeV and > 300 MeV electron KET channels, collected from launch up to the end of 1995 after completion of the Ulysses prime mission. Regarding low energy electrons, the stress is put on…
Candidate polar-ring galaxies in the Hubble Deep Field.
Reshetnikov, V. P.
We discuss the properties of two peculiar galaxies (2-809 and 2-906) selected in the Hubble Deep Field as possible candidates to high-redshift (z=~1) polar-ring galaxies. We found that the presence of polar-ring galaxies in a random deep field gives some support for a galaxy interaction rate steeply increasing with redshift.
EUV Emission from RS Canum Venaticorum binaries.
Doyle, J. G.; Mathioudakis, M.; Mitrou, C. K. +1 more
We performed a study of 104 RS CVn systems in the extreme ultraviolet (EUV) using the all-sky survey data obtained by the Extreme Ultraviolet Explorer (EUVE). The present sample includes several new RS CVn detections; 11 more than in the published EUVE catalogs, and 8 more than in the ROSAT Wide Field Camera catalog. The ratio of detections to non…
Simultaneous Spectroscopy and Imaging of the Jovian Aurora with the Hopkins Ultraviolet Telescope and the Hubble Space Telescope
Wolven, Brian C.; Feldman, Paul D.; Strobel, Darrell F. +4 more
Simultaneous ultraviolet spectra and images of the north polar aurora of Jupiter were obtained on 1995 March 9 with the Hopkins Ultraviolet Telescope (HUT) and the Hubble Space Telescope (HST). This unique data set contains a well-calibrated flux measurement that includes all of the H2 Lyman and Werner band emission from 900 to 1650 Å, …
Reappearance of recurrent low-energy particle events at Ulysses/HI-SCALE in the northern heliosphere
Simnett, G. M.; Lanzerotti, L. J.; Armstrong, T. P. +4 more
In the high-latitude northern hemisphere of the heliosphere, the Heliosphere Instrument for Spectra Composition and Anisotropy at Low Energies (HI-SCALE) energetic particle detectors on Ulysses have measured quasi-recurrent ~26-day increases of 40-65 keV electrons during 11 solar rotations from October 1995 through July 1996. They do not appear on…
Abundance analysis of the slow nova PW Vulpeculae 1984
Shore, Steven N.; Hauschildt, Peter H.; Schwarz, Greg J. +1 more
We determine the elemental abundances for the ejecta of the slow nova PW Vul 1984. Our technique uses a minimization of the emission-line fits of a photoionization model to available ultraviolet, optical and infrared spectra. We find the following abundances (by number) with respect to solar: He/H=1.0+/-0.4, C/H=7.0^+7_-4, N/H=85^+59_-41 and O/H=6…
Evidence for an Anomalous State in the Black Hole Candidate 4U 1630-47
Kuulkers, Erik; van der Klis, Michiel; Parmar, Arvind N.
We have reanalyzed two EXOSAT medium-energy observations during part of the 1984 X-ray outburst of the black hole candidate transient system 4U 1630-47. One observation (May 10) shows fast-timing properties (on timescales shorter than ~250 s) typical of those of other black hole candidates in their high states. The power spectrum shows a power law…
Gamma-Ray Burst Arrival Time Localizations: Simultaneous Observations by Mars Observer, Compton Gamma Ray Observatory, and ULYSSES
Hurley, K. C.; Fishman, G. J.; Kouveliotou, C. +12 more
Between 1992 October 4 and 1993 August 1, concurrent coverage by the Compton Gamma Ray Observatory (CGRO), Mars Observer (MO), and Ulysses spacecraft was obtained for 78 gamma-ray bursts (GRBs). Although most of these were below the MO and Ulysses thresholds, nine were positively detected by all three spacecraft, with data quality adequate for qua…
Dynamic Processes in Be Star Atmospheres. VI. Simultaneous X-Ray, Ultraviolet, and Optical Variations in λ Eridani
Smith, Myron A.; Corcoran, M. F.; Murakami, T. +4 more
We document the results of simultaneous wavelength monitoring of the B2e star λ Eri. This campaign was carried out from ground stations and with the ROSAT, ASCA, IUE, and Voyager 2 space platforms during a week in 1995 February-March a smaller follow-up was conducted in 1995 September. During the first of these intervals λ Eri exhibited extraordin…