Search Publications
Correlation of Ultraviolet and Radio Flux in Three Active Galactic Nuclei
Shukla, Hemant; Stoner, Ronald E.
We report the results of a search for correlations between the time- variable ultraviolet (UV) and the radio flux in three AGNs, viz., 3C 273, 3C 120, and PKS 2155-304. Data from 1984 to present were used. UV data from the short-wave IUE camera were downloaded from the IUE Regional Data Analysis Facility and the National Space Science Data Center …
NE V and NE VI Lines in the Ultraviolet Spectrum of the Symbiotic Star RR Telescopii
Feibelman, W. A.; Keenan, F. P.; McKenna, F. C. +2 more
New theoretical Ne VI] electron density-sensitive ratios are presented for the intercombination transitions R1 = I(1006.1 Å)/I(999.6 Å) and R2 = 1(1010.6 Å)/I(999.6 Å). Temperature-sensitive ratios are also given for the Ne V] ratio R = 1(1137.0 Å)/I(1574.8 Å). We discuss the potential usefulness of these line ratios for stud…
Solar cycle dependence of the solar wind dynamics: Pioneer, Voyager, and Ulysses from 1 to 5 AU
Smith, Edward J.; González-Esparza, J. Américo
Significant differences between Pioneer and Voyager observations were found in solar wind structure between 1 and 6 AU. These disagreements were attributed to temporal effects related to the solar cycle, but no unifying study of Pioneer-Voyager observations was performed. On the basis of maps of large-scale features we unify previous reports of Pi…
IUE and Optical Spectra of AL Comae Berenices During a Rare Superoutburst
Moreno, H.; Szkody, Paula; Howell, Steve B. +4 more
We present optical spectra from 3 to 21 days and lUE spectra at 10 and 19 days following the outburst of the extreme amplitude, very short orbital period cataclysmic variable AL Corn after a 20 yr quiescent interval. The lUE spectra have no evidence of P Cyg profiles and show an early presence of Lyα absorption, which may be indicative of a 25,000…
Interplanetary observations of solar g-mode oscillations?
Riley, Pete; Sonett, C. P.
By applying spectral techniques to magnetic field and plasma data from Helios 1 and 2, Pioneer 1 and 2, and Voyager 1 and 2 missions, an attempt has been made to find evidence for solar g-mode oscillations in the solar wind. It is demonstrated that analysis employing simple spectral techniques is unlikely to detect such oscillations. Using the mul…
ULYSSES spacecraft observations of radio and plasma waves: 1991-1995.
Balogh, A.; MacDowall, R. J.; Phillips, J. L. +3 more
The radio and plasma wave investigation of the Ulysses spacecraft mission provided nearly continuous observations of wave electric fields (less than 1MHz) and magnetic fields (less than 450 Hz) from spacecraft launch in late 1990 through perihelion in 1995 and beyond. The Ulysses spacecraft reached heliographic latitudes of +/-80deg, providing a u…
First HST/FOC images of the low mass companion of the astrometric binary Gliese 623.
Barbieri, C.; Nota, A.; Ragazzoni, R. +4 more
We have resolved the astrometric binary Gliese 623 into two components, by direct imaging in the visible band, with the COSTAR corrected FOC. The images clearly show the faint companion Gliese 623B, with a derived absolute magnitude of M_V_=16.17+/-0.10, at a distance of 0.33" from the primary (namely at 2.51AU, assuming a parallax of π=0.132", i.…
Comet Shoemaker-Levy 9 Dust
Mumma, Michael J.; Hahn, Joseph M.; Rettig, Terrence W.
Comet Shoemaker-Levy 9 (S-L 9) was imaged with the Hubble Space Telescope from January 1994, through solar opposition on April 29, and until impact in July 1994. As noted by several observers, no anti-sunward dust tails were detected east of the fragments after opposition (D. Jewitt and J. Chen 1994,Periodic Comet Shoemaker-Levy 9(1993e), IAU Circ…
First Cycle 4 multiwavelength observations of the gamma-ray quasar PKS 0208-512.
Vestrand, W. T.; Sreekumar, P.; Kubo, H. +3 more
We present first results of CGRO Cycle 4 multiwavelength observations of the gamma-ray quasar PKS 0208-512. A bright, variable gamma-ray source, PKS 0208-512 has been detected numerous times by the EGRET experiment aboard the CGRO, possessing one of the hardest spectra observed to date. The recent COMPTEL observations of Blom et al. (1995A&A..…
Rotational modulation and flares on RS Canum Venaticorum and BY Draconis stars. XIX. Simultaneous IUE, ROSAT, VLA, and visual observations of TY Pyxidis.
Pagano, I.; Linsky, J. L.; Neff, J. E. +4 more
In November 1990, we observed the eclipsing binary system TY Pyxidis with the IUE satellite simultaneously with the ROSAT All-Sky Survey. The IUE and ROSAT/WFC observations covered the 3.2-day period of this system continuously, while the ROSAT/PSPC coverage was limited to 2.26days. We also observed TY Pyx with the VLA for a total of 22 hours thro…