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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…
Interstellar Gas in Low Mass Virgo Cluster Spiral Galaxies
Madden, Suzanne C.; Smith, Beverly J.
We have measured the strengths of the [C II] 158 mu m, [N II] 122 mu m, and CO (1 - 0) lines from five low blue luminosity spiral galaxies in the Virgo Cluster, using the Infrared Space Observatory and the NRAO 12m millimeter telescope. Two of the five galaxies have high L([C II])/L(CO) and L(FIR)/L(CO) ratios compared to higher mass spirals. Thes…
High-Resolution Imagery of BD + 30degree3639 and Its Dusty Halo
White, Stephen M.; Borkowski, Kazimierz J.; Harrington, J. Patrick +1 more
The planetary nebula BD +30\arcdeg3639 has been imaged by the Hubble Space Telescope through nine narrow-band filters. A high resolution radio map has been obtained with the VLA. Comparison of Hβ , Hα and radio images allow us to derive the point-to-point variations in both the extinction and the ratio of total to selective absorption. The extinct…
In-Flight Performance of the Virgo Luminosity Oscillations Imager Aboard SOHO
Appourchaux, Thierry; Andersen, Bo N.; Fröhlich, Claus +3 more
The Luminosity Oscillations Imager (LOI) is a part of the VIRGO instrument aboard the Solar and Heliospheric Observatory (SOHO). The scientific objective of the LOI experiment is to identify and characterize pressure and internal gravity oscillations of the Sun by observing the radiance variations. The LOI is a low-resolution imager with 12 pixels…
Observations of Doppler Shifts in a Solar Polar Coronal Hole
Wilhelm, K.; Mariska, J. T.; Warren, H. P.
Using observations from the Solar Ultraviolet Measurements of Emitted Radiation experiment flown on the Solar and Heliospheric Observatory spacecraft, we have measured Doppler wavelength shifts in the north polar coronal hole in the 1032 and 1038 Å emission lines of O VI and the 1036 and 1037 Å emission lines of C II relative to chromospheric emis…
Tomographic Separation of Composite Spectra. IV. The Physical Properties of the Massive Close Binary DH Cephei
Gies, Douglas R.; Penny, Laura R.; Bagnuolo, William G., Jr.
We present the results of a Doppler tomographic reconstruction of the UV spectra of the double-lined, O binary DH Cephei based on observations made with the International Ultraviolet Explorer. We describe cross-correlation methods we use to obtain precise radial velocities, and we present a radial velocity curve based on combined optical and UV me…