Search Publications
Is there really a supermassive black hole in M87?
Marconi, A.; Macchetto, F. D.; Capetti, A. +3 more
We present the first HST long-slit spectrum of a gaseous disc around a candidate supermassive black hole. The results of this study on the kinematics of the gaseous disc in M87 are a considerable improvement in both spatial resolution and accuracy over previous observations, and require a projected mass of MBH(sin i)2 = (2.0±…
Variations of the stellar wind in early-B hypergiants.
Stahl, O.; Wolf, B.; Lamers, H. J. G. L. M. +9 more
With our fiber-linked echelle spectrograph we monitored three early-B hypergiants with high dispersion and good coverage in time. The program stars ζ^1^ Sco (HD 152236), HD 169454, and HD 190603 were observed over periods of several months in several seasons. In the years 1990 to 1994, we covered the wavelength range from 4000Å to 6740Å and in 199…
1995 observations of Martian dust storms using the Hubble Space Telescope
Bell, James F., III; Wolff, Michael J.; Clancy, R. Todd +3 more
A synoptic monitoring program of Mars using the Wide Field Planetary Camera 2 on board the Hubble Space Telescope has resulted in the observation of discrete dust activity for two dates following the 1995 opposition. Data obtained on April 8 (LS=82°) and August 21, 1995 (LS=145°) reveal the presence of local dust storms in th…
The Orbit of Charon
Buie, Marc W.; Tholen, David J.
The orbit of Charon has been determined from 60 images of the Pluto-Charon system acquired with the Hubble Space Telescope Wide Field and Planetary Camera between 1992 May 21 and 1993 August 18. The semimajor axis was found to be 19,636 ± 8 km, in good agreement with an older determination upon which mutual-event-based radius computations have rel…
Isotopic Abundances of Fe and Ni in Galactic Cosmic-Ray Sources
Simpson, J. A.; Connell, J. J.
With a new instrument, designed to determine the isotopic composition of Galactic cosmic-ray nuclei, on board the Ulysses spacecraft, we report relative abundance measurements for 54Fe, 55Fe, 56Fe, 57Fe, 58Fe and 58Ni, 59Ni, 60Ni, 62Ni in the overall…
Mid-IR colors and star formation in Virgo and Coma galaxies.
Boulanger, F.; Sauvage, M.; Contursi, A. +9 more
We present observations of the global emission of a sample of spiral and irregular galaxies in the Virgo cluster and the Coma supercluster. These observations have been made with the camera ISOCAM on board the Infrared Space Observatory, through two broad filters centered respectively at 6.75 and 15.0µm. The corresponding fluxes are correcte…
Analytical dynamical models for double power-law galactic nuclei
Zhao, Hongsheng
Motivated by the finding that the observed surface brightness profiles of many galactic nuclei are fitted well by double power laws, we explore a range of spherical self-consistent dynamical models with this light profile. We find that the corresponding deprojected volume density profile, phase- space density and line-of-sight velocity distributio…
Multiwavelength Monitoring of the BL Lacertae Object PKS 2155-304 in 1994 May. II. The IUE Campaign
Shull, J. Michael; Urry, C. Megan; Madejski, Greg +16 more
PKS 2155-304, the brightest BL Lac object in the ultraviolet sky, was monitored with the International Ultraviolet Explorer satellite at ~1 hr time resolution for 10 nearly uninterrupted days in 1994 May. The campaign, which was coordinated with Extreme Ultraviolet Explorer, ROSAT, and ASCA monitoring, along with optical and radio observations fro…
A photometric and spectroscopic study of the symbiotic binary BFCyg
Bode, M. F.; Errico, L.; Vittone, A. +3 more
We present the historical 1890-1996 photographic/B-band light curve of the symbiotic binary BF Cyg for the first time. It displays three types of eruption: (i) a slow, symbiotic nova outburst (1895-1960), probably caused by a thermonuclear event; (ii) short-term flares dependent on the orbital phase, possibly triggered by accretion events, and (ii…
Hubble Space Telescope Images of Asteroid 4 Vesta in 1994
Wells, Eddie N.; Storrs, Alex D.; Thomas, Peter C. +4 more
The Planetary Camera of the WFPC2 on board the Hubble Space Telescope was used in late 1994 to record 56 images of Asteroid 4 Vesta in four compositionally diagnostic wavelength bands. The images were taken at eight epochs to give global coverage of Vesta at an aspect of approximately 16° north latitude. The prograde rotation of Vesta is clearly r…