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Multifrequency Observations of the Blazar PKS 0537-441 in a Moderately Active State
Maraschi, L.; Tanzi, E. G.; Chiappetti, L. +6 more
PKS 0537-441 was observed during an active state in February 1985 at infrared, optical, UV, and X-ray frequencies. Comparison with earlier measurements indicates that the source brightened by a factor of approximately 2 in all bands. This suggests that the same spatial region may be responsible for the emission in the whole spectral range observed.
Dust in the Emission-Line Gas of the Seyfert 2 Galaxy Markarian 3
Harrington, J. P.; Kraemer, S. B.
The results of photoionization models of the emission-line gas of the type 2 Seyfert galaxy Mrk 3 are presented. The models include cosmic dust with spectral properties similar to that found in the Galaxy. The effect of dust within the gas on the transfer of line radiation, particularly the UV resonance lines, and the contribution of the hot dust …
More Low-Redshift Broad Absorption Line QSOs
Turnshek, David A.; Grillmair, Carl J.
The discovery of two new broad absorption line (BAL) QSOs with emission redshifts of 1.024 and 0.129 is reported. The discovery of the two new low-redshift BAL QSOs strengthens the evidence that the fraction of QSOs with BALs at low redshifts is similar to the 3-10-percent fraction found at higher redshifts. In particular, the analysis suggests th…
A Survey of Interstellar Sulfur Abundance and Implications for P II Oscillator Strengths
Harris, A. W.; Mas Hesse, J. M.
A study of interstellar gas-phase S abundance is presented which is based mainly on abundances for 39 sight lines newly derived from recently published Copernicus UV absorption-line measurements and archival IUE data. A trend of increasing depletion with increasing mean H volume density n-bar(H) is evident which is similar to that already establis…
Near-Ultraviolet Spectroscopy of Seyfert Nuclei: Reddening and Bowen Fluorescence
Malkan, Matthew A.
Spectra with high signal-to-noise ratios extending down to the atmospheric ultraviolet cut-off have been obtained for 11 Seyfert nuclei with narrow emission lines. In all objects the He II lines at 3204 A and 4686 A were measured simultaneously. Their ratio gives an estimate of reddening accurate to 0.14 mag in E(B-V). The redshifts of nine of the…
Neutral Oxygen and Sulfur Densities in the Io Torus
Skinner, T. E.; Durrance, S. T.
Ultraviolet spectra (1150-1750 A) of the Io torus, obtained using a rocket-borne telescope and spectrometer in May 1981, show emissions of neutral sulfur and neutral oxygen, as well as ionic emissions of S II, S III, and S IV. The emissions are observed almost 180 deg from the location of the satellite Io and imply the existence of an extended neu…
EXOSAT Results on V426 Ophiuchi: Indications of a DQ Herculis System
Szkody, P.
EXOSAT LE and ME data reveal a sinusoidal l hr modulation during the 6 hr binary orbit of the cataclysmic variable V426 Oph. The amplitude and shape of this modulation, the X-ray fluxes and spectrum, as well as the time scales involved argue for a DQ Her interpretation. In this case, the white dwarf in V426 Oph has the longest rotation period amon…
EXOSAT Observations of 3C 371
Worrall, D. M.; Brunner, H.; Staubert, R.
The N galaxy/BL Lacertae object 3C 371 was observed by EXOSAT on two occasions separated by 18 days in September 1984. The low-energy and medium-energy X-ray flux has varied on the time scale of years (in comparison with HEAO 1 and Einstein Observatory measurements), 18 days (between the authors' two observations), and 8 hr to about 25 minutes wit…
Epsilon Aurigae: Polarization, Light Curves, and Geometry of the 1982--1984 Eclipse
Ake, T. B.; Simon, T.; Kemp, J. C. +5 more
Polarization and light curves of the recent eclipse of ɛ Aur are presented and modeled, using a tilted, opaque secondary disk and a model atmosphere for the F Ia primary star. That model qualitatively explains the striking asymmetries in the observed curves. But out-of-eclipse polarimetry shows the primary to be a nonradial pulsator, and this will…
Variability of Ultraviolet Emission in the Carbon Star TX PISCIUM
Johnson, Hollis R.; Baumert, John H.; Querci, Francois +1 more
Multiple low-resolution IUE observations of the cool carbon star TX Psc (NO; C6,2) permit an analysis of the variations in strength of the strongest emission lines - the Mg II line at 2800 Å, the C II line at 2330 Å, and certain Fe II lines. In the present sample of nine spectra, the integrated flux of the Mg II line varies by at least a factor of…