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IUE and Voyager Observations of the Unusual Cataclysmic Variable S193
Garnavich, Peter; Szkody, Paula; Holberg, Jay +2 more
UV observations of S193 were obtained with Voyager and the IUE satellite during both high and low states of this unusual object. Voyager only detected the source during the high state, where the continuum looks similar to the novalike IX Vela and dwarf novae at outburst. The IUE spectra at the high state show deep absorption lines, but the line ra…
The Long-Term Periodic Oscillation of the NGC 4151 Nucleus
Lyuty, V. M.; Kotov, V. A.; Haneychuk, V. I. +3 more
The hypothesis that the luminosity of the nucleus of the Seyfert 1 galaxy NGC 4151 varies with a period of P0 ~ 160.0101 minutes is revised. In 1987-1994 a series of photometric observations of the NGC 4151 has been carried out in the U and V filters at several instruments. In the total sample of 27 nights, the U data of 15 nights showe…
Evidence Against Broad Absorption Lines in the X-Ray-bright Quasar PG 1416-129
Green, Paul J.; Mathur, Smita; Schartel, Norbert +1 more
Recent results from the ROSAT All-Sky Survey and from deep ROSAT pointings reveal that broad absorption line quasars (BALQSOs) are weak in the soft X-ray bandpass (αox > 1.8) in comparison to QSOs with normal OUV spectra (αox = 1.4). One glaring exception appeared to be the nearby BALQSO PG 1416-129, which is a bright ROSA…
Coronal and Interplanetary Particle Beams
Aschwanden, Markus J.; Treumann, Rudolf A.
In this report we attempt to synthesize the results of a series of working group discussions focused on the topics of particle beams and particle acceleration in the solar corona and in interplanetary space. We start our discussion of coronal beams with a standard flare scenario, established on recent X-ray (Yohkoh, CGRO) and radio observations, w…
Spatial variations of 0.2 to 5 MeV protons in the 1-5 AU in-ecliptic region from Ulysses, Voyager 1 and 2, and IMP 8 gradient studies
Armstrong, Thomas P.; Boufaida, Moncef
Protons with energies ranging from 0.3 to 2 MeV are nearly always present in the environment of Earth. Solar flare events and interplanetary shock waves can be identified as producing or enhancing these fluxes. However, interplanetary particles are observed even in the absence of solar flares. Explaining the presence of these proton fluxes in the …
A survey of vacuum-ultraviolet extinction curves based on International Ultraviolet Explorer spectra
Patriarchi, P.; Megier, A.; Aiello, S. +1 more
This paper presents the interstellar extinction curves derived from the International Ultraviolet Explorer (IUE) spectra with the aid of the already published `artificial standards'. The variety of possible shapes of the curves, demonstrated earlier on spectra from the TD/1 satellite, is fully confirmed.
Ulysses observations of short-period (≤30 Days) modulation of the galactic cosmic rays
Keppler, E.; Kunow, H.; Heber, B. +3 more
A frequency analysis of the short-period modulation of the GCR as seen by instruments aboard Ulysses shows interesting temporal variations. In particular, during an approximate five-month period from December 1993 to May 1994, the modulation was not the usual 26 days but more than 29 days. The CIR-associated MeV ions did not exhibit this period sh…
The heliospheric magnetic field at solar minimum as observed by ULYSSES
Balogh, A.; Horbury, T. S.; Smith, E. J. +1 more
Since February 1992 the Ulysses spacecraft has been in a polar orbit round the Sun, reaching 80 deg heliolatitude over the south pole in September 1994 and over the north pole in July 1995. During this time solar activity has been gradually declining towards its present minimum in mid-1996. We discuss how the large scale configuration of the helio…
The Latitudinal Structure of the Solar Wind in the Vicinity of the Solar Equator near Solar Minimum: 1986 and Predictions for 1997
Gazis, P. R.
In situ observations by different spacecraft have shown that the heliospheric current sheet (HCS) is associated with a narrow band of low speed high density solar wind. The inclination of the HCS and the three-dimensional structure of solar wind streams is related to the inclination of the coronal neutral line. Observations from the Ulysses spacec…
First Observations of Coronal Hole Structure and Evolution Using Soho-Cds
Harrison, R. A.; Moore, V.; Insley, J. E.
We report on initial observations of coronal holestructure and evolution by the Coronal Diagnostic Spectrometer (CDS) instrument on board the Solar and Heliospheric Observatory (SOHO). The data show that there is coronal activity on time scales of tens of minutes, manifested as brightenings at chromospheric network cell junctions in extreme ultrav…