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Cooling Flow in the 2A 0335+096 Cluster of Galaxies
Singh, K. P.; Westergaard, N. J.; Schnopper, H. W.
We present the surface brightness distribution of hot intracluster gas in the 2A 0335+096 cluster of galaxies, obtained from X-ray imaging observations with the Einstein Observatory and the EXOSAT Observatory. The intracluster gas is found to be nonisothermal. The surface brightness is deprojected to obtain density and temperature profiles of the …
Ultraviolet Spectroscopy of R Coronae Borealis
Holm, A. V.; Doherty, L. R.
Observations of the hydrogen-deficient supergiant R CrB were obtained with the IUE over an interval of 54 days in order to study the nature of this star's irregular, small-amplitude variations in light. By chance, the series of observations coincided with a dip in the light intermediate between the normal fluctuations and the deep declines associa…
An Improved Photometric Analysis of SX Aurigae
Peters, Geraldine J.; Linnell, Albert P.; Polidan, Ronald S.
The photometric analysis reported leads to four principal conclusions: 1. The SX Aur system consists of two normal main-sequence stars. The components are very close to the inner Roche limiting surface. 2. The primary component is extremely close to contact with its inner Roche lobe, as well as can be judged from the photometric solution. It is in…
Detection of Extragalactic Absorption in the Ultraviolet Spectrum of the BL Lacertae Object PKS 2155-304
Maraschi, L.; Tanzi, E. G.; Treves, A. +2 more
The complete collection of ultraviolet spectra (1200-3000 A) of PKS 2155-304 taken with IUE in l979-1986 is reanalyzed with the aim of producing a high signal-to-noise ratio spectrum. As a result of co-adding the best exposed spectra a number of absorption lines are found, most of which can be identified with expected interstellar species in our G…
Comet P/Encke's Nongravitational Force
A'Hearn, Michael F.; Schleicher, David G.
A nearly direct measurement of the nongravitational force on a cometary nucleus is presented. IUE spectra of comet P/Encke show significant Greenstein effects even when centered on the nucleus. These imply net heliocentric components of outflow of 1.6 and 0.3 km/s for the OH radicals before and after perihelion near r = 0.8 AU. This implies a larg…
Ultraviolet and Radio Flares from UX ARIETIS and HR 1099
Willson, Robert F.; Lang, Kenneth R.
Simultaneous observations of the RS CVn systems UX Ari and HR 1099 with the IUE satellite and the VLA are presented. Flaring activity is observed at ultraviolet wavelengths with the IUE when none is detected at radio wavelengths with the VLA. Radio flares with no detectable ultraviolet activity have also been observed. Thus, flares in the two spec…
Recent Unusual Activity in the Be Star FY Canis Majoris
Peters, Geraldine J.
Unusual activity observed in the circumstelar envelope of FY CMa during April-May, 1987 is reported. Nightly CCD observations from April 16-20 revealed an invariant H-alpha emission feature and a simple absorption profile for He I 6678 with very weak double emission components. Similar observations on May 2, however, showed that the V lobe of the …
Search for Linear Polarization in Gamma-Ray Sources: Possible Evidence for the VELA Pulsar
Caraveo, P. A.; Bignami, G. F.; Mitrofanov, I. +1 more
The use of the azimuthal distribution of planes containing e(+)/e(-) pairs from high-energy photon materialization to investigate the nature of gamma-ray sources is discussed. Analytical work done on COS B data for bright COS B sources (Vela, Crab, and Geminga) and for a reference background region is presented along with results which are indicat…
Ultraviolet Spectroscopy of the ``Jetlike'' Condensations of NGC 4151
Bruhweiler, F. C.; Smith, Andrew M.
The spectrometers aboard the International Ultraviolet Explorer (IUE) are used to obtain UV spectroscopy of the jetlike condensations seen extending 18" from the nucleus of the nearby Seyfert 1 galaxy NGC 4151. New data reduction techniques are used to detect, delineate, and measure weak nebular emission in IUE spectra. Spatially resolved extended…
Voyager and IUE Observations of 3C 273: Detection of Possible Lyman Continuum Absorption in a Nearby (z = 0.158) Quasar
Reichert, G. A.; Carone, T. E.; Wu, C. -C. +1 more
We report results of near-simultaneous IUE and Voyager ultraviolet spectrometer (UVS) observations of 3C 273, obtained during the period of 1985 late July-early August. The data cover a total combined wavelength range 500-3200 A (observed frame). This is the first time that observations shortward of 1200 A have been obtained for any extragalactic …