The distribution of ionized, molecular, and atomic hydrogen in the disk and especially along the spiral arms of the Whirlpool galaxy, M51, is investigated by...
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PublicationStar formation efficiency patterns in the spiral arms of M51
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PublicationStar formation in Seyfert galaxies
An analysis of IRAS data for a sample of classical (optically selected) Seyfert galaxies is presented. The IRAS fluxes at 25, 60, and 100 μm are found to be...
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PublicationSteps toward determination of the size and structure of the broad-line region in active galactic nuclei. 5: Variability of the ultraviolet continuum and emission lines of NGC 3783
We report on the results of intensive ultraviolet spectral monitoring of the Seyfert 1 galaxy NGC 3783. The nucleus of NGC 3783 was observed with the...
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PublicationSteps toward determination of the size and structure of the broad-line region in active galactic nuclei. 6: Variability of NGC 3783 from ground-based data
The Seyfert 1 galaxy NGC 3783 was intensely monitored in several bands between 1991 December and 1992 August. This paper presents the results from the ground...
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PublicationSteps toward determination of the size and structure of the broad-line region in active galactic nuclei. I - an 8 month campaign of monitoring NGC 5548 with IUE
Emission-line and UV continuum observations of the type I Seyfert galaxy NGC 5548 were carried out for a period of 8 months with the IUE satellite. It was found...
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PublicationSteps toward determination of the size and structure of the broad-line region in active galactic nuclei. II - an intensive study of NGC 5548 at optical wavelengths
A large, international program of ground-based optical spectroscopy and photometry of the variable Seyfert 1 galaxy NGC 5548 undertaken in support of an IUE...
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PublicationSteps toward determination of the size and structure of the broad-line region in active galactic nuclei. IV - Intensity variations of the optical emission lines of NGC 5548
Measurements of optical emission-line flux variations based on spectra of the Seyfert galaxy NGC 5548 obtained between December 1988 and October 1989 are...
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PublicationThe 160 minute solar oscillation - an artifact?
Analysis of data obtained over the years 1980-1985 are analyzed to show that the period of the 160-minute signal is indeed 160.00 minutes. It is demonstrated...
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PublicationThe circumstellar region of NGC 5728
A 2D array of optical fibers generating simultaneous spectral and spatial information has been used to observe the central 13 arcsec of NGC 5728; on this basis...