Search Publications
A Gravitational Lens Candidate Discovered with the Hubble Space Telescope
Filippenko, Alexei V.; Maoz, Dan; Schneider, Donald P. +6 more
We report evidence for gravitational lensing of the high-redshift (z = 3.8) quasar 1208+101, observed as part of the Snapshot Survey with the Hubble Space Telescope Planetary Camera. An HST V image taken on gyroscopes resolves the quasar into three point-source components, with the two fainter images having separations of 0.1" and 0.5" from the ce…
Twin Peaks: IC 4329A and Arakelian 120
Marziani, P.; Sulentic, J. W.; Calvani, M.
New spectrophotometric observations of the Seyfert 1 galaxies IC 4329A and Arakelian 120 are presented. The low-ionization broad emission lines (as evidenced by Hβ) are strikingly similar. The so-called zero peak in the Balmer lines of these objects appears to be both broader than and blueshifted relative to the [O III] λλ4959, 5007 lines. It is a…
The Near-Ultraviolet Spectrum of Markarian 205
Jenkins, Edward B.; Schneider, Donald P.; Jannuzi, Buell T. +2 more
We report measurements of the absorption and of the emission lines between 1600 and 3200 A in the spectrum of the nearby AGN Markarian 205 (z = 0.071), which lies at a projected distance of 3 kpc (H_0_= 100 km s^-1^) from the nucleus of the nearby barred spiral galaxy NGC 4319 (z = 0.0047). The results were obtained using high-resolution (R = 1300…
Ultraviolet Imaging Telescope Observations of the Cygnus Loop
Jenkins, Edward B.; Gull, Theodore R.; Cheng, Kwang-Ping +8 more
Attention is given to UV images of a 40-arcmin field in the northeast part of the Cygnus Loop made by the Ultraviolet Imaging Telescope (UIT) during the Astro-1 mission in December 1990. The longest FUV (B5) exposure is compared with ground-based and X-ray observations and with models. It is inferred from SNR shock models that C IV 1550 A dominate…
Comparing Restored HST and VLA Imagery of R Aquarii
Hollis, J. M.; Yusef-Zadeh, F.; Dorband, J. E.
The maximum entropy method is applied to Hubble Space Telescope data taken of the R Aquarii binary system and its jet with the Faint Object Camera in order to restore an image in forbidden O III at 5007 A plagued by spherical aberration and detector saturation. These results are compared with 2-cm radio continuum imagery taken with the Very Large …
The Diffuse Interstellar Cloud toward HD 179406 (20 Aquilae)
Snow, Theodore P.; Black, John H.; Hanson, Margaret M.
An analysis of the diffuse interstellar cloud complex in front of HD 179406 (20 Aql) is presented. Along this sight line, multispectral absortion- and emission-line studies have uncovered at least three distinct velocity components due to individual clouds. A dominant velocity component is seen in both the absorption and emission-line data sets at…
The Ultraviolet-bright Stars of Omega Centauri, M3, and M13
O'Connell, Robert W.; Hill, Robert S.; Bohlin, Ralph C. +7 more
Two new UV-bright stars detected within 2 arcmin of the center of Omega Cen are spectroscopically investigated with the short-wavelength spectrograph of the IUE. The IUE spectra of the UV-bright stars UIT-1 and UIT-2 in the core of Omega Cen superficially resemble those of Population I mid-B stars. The absorption lines of the core UV-bright stars …
Inner Shell of Optically Thin Gas in Active Galactic Nuclei
Zheng, Wei
The Lyα and Balmer line profiles in more than 50 Seyfert 1 galaxies and QSOs are studied. Approximately 60% of the objects show similar profiles, 25% show smaller FWHM of Hβ or Hα. In five objects the Lyα profiles have stronger wings than the Balmer lines. The Lyα/Balmer ratio increases along both wings, suggesting an inner envelope of a very broa…
Coordinated Ginga, IUE, and VLA Observations of Stellar Activity in sigma 2 Coronae Borealis
Walter, F.; Vilhu, O.; Stern, R. A. +5 more
Observations of the active cool star binary system Sigma(2) Corona Borealis with the Large Area Counters on the Ginga X-ray satellite over 2.5 d, or about two orbital periods, are reported. Throughout the observations, Sigma(2) CrB exhibited X-ray variability on time scales ranging from tens of minutes to hours. The X-ray light curve shows evidenc…
Hubble Space Telescope Spectroscopy of OB Stars in M31
Bianchi, L.; Hutchings, J. B.; Lamers, H. J. G. L. M. +2 more
We have obtained UV spectra of two luminous hot stars in M31 with the Hubble Space Telescope. The stars are of late O and WN spectral type and lie on opposite sides of M31. We derive UV extinction curves for M31 which differ from both the Galaxy and the LMC. We find differences between the 15 absorbers in both lines of sight in M31 and in the Gala…