Search Publications
Hubble Space Telescope Imaging of the Seyfert 2 Galaxy NGC 2110
Heckman, Timothy M.; Mulchaey, John S.; Bower, Gary A. +3 more
Hubble Space Telescope (HST) images of the Seyfert 2 galaxy NGC 2110 in the emission lines of [O III] λλ4959,5007 and Hα + [N II] λλ6548,6584 and the nearby continuum are presented. After deconvolution, the resolution of these images is ~0.1", corresponding to a linear scale of ~23 pc at the assumed distance (46.8 Mpc) to this galaxy. The dominant…
Cooling of the White Dwarf in U Geminorum between Outbursts
Szkody, Paula; Sion, Edward M.; Long, Knox S. +1 more
We have obtained far-ultraviolet (1150-1610 A) spectra of U Gem with the Faint Object Spectrograph on the Hubble Space Telescope approximately 13 and 70 days after the end of a normal dwarf nova outburst of the system. Both spectra appear dominated by the White Dwarf (WD) in U Gem. At 1400 A, the flux from U Gem declined approximately 28% between …
Multiwavelength Study of the Magnetically Active T Tauri Star HD 283447
Feigelson, Eric D.; Phillips, Robert B.; Imhoff, Catherine +4 more
We observed the luminous T Tauri star HD 283447 = V773 Tauri simultaneously at X-ray, ultraviolet, optical photometric and spectroscopic, and radio wavelengths for several hours on UT 1992 September 11. ROSAT, IUE, Very Large Array (VLA) and an intercontinental Very Long Baseline Interferometry (VLBI) network, and three optical observatories parti…
Galaxy Mergers and Gravitational Lens Statistics
Maoz, Dan; Rix, Hans-Walter; Turner, Edwin L. +1 more
We investigate the impact of hierarchical galaxy merging on the statistics of gravitational lensing of distant sources. Since no definite theoretical predictions for the merging history of luminous galaxies exist, we adopt a parameterized prescription, which allows us to adjust the expected number of pieces comprising a typical present galaxy at z…
Highly Ionized Gas Absorption in the Disk and Halo toward HD 167756 at 3.5 Kilometers per Second Resolution
Sembach, Kenneth R.; Savage, Blair D.; Cardelli, Jason A.
High-resolution spectra of interstellar Si IV, C IV, and N V absorption lines along the 4 kpc path to the inner Galaxy star HD 167756 at z = -0.85 kpc are presented. The spectra were obtained with the echelle mode of Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST) and have signal-to-noise ratios ranging from 23 …
Network Synthesis Localization of Two Soft Gamma Repeaters
Cline, T.; Kouveliotou, C.; Sommer, M. +5 more
We introduce the method of 'network synthesis,' which allows the detection of very weak gamma-ray transient signals in the data of the Ulysses gamma-ray burst (GRB) experiment from repeating sources. It consists of defining a grid of alpha, delta values, and for each BATSE detection of a burst from a soft gamma repeater, predicting the arrival tim…
The Far-Ultraviolet Dust Albedo in the Upper Scorpius Subgroup of the Scorpius OB2 Association
Gordon, Karl D.; Witt, Adolf N.; Carruthers, George R. +2 more
During NRL's Far Ultraviolet Cameras experiment on STS-39, four images of the giant reflection nebula encompassing the Upper Scorpius subgroup of the Sco OB2 association were obtained in two ultraviolet bandpasses with lambdaeff = 1362 A and 1769 A. From these images and IUE and TD-1 stellar spectra, the ratio of nebular to stellar flux…
Observing Stellar Coronae with the Goddard High Resolution Spectrograph. I. The dMe Star AU Microscopii
Carpenter, K. G.; Linsky, J. L.; Shore, S. N. +11 more
We report on an observation of AU Mic taken with the Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope. The data consist of a rapid sequence of spectra covering the wavelength range 1345-1375 A with a spectral resolution of 10,000. The observations were originally intended to search for spectral variations during flares…
WFPC2 Observations of the Double Cluster NGC 1850 in the Large Magellanic Cloud
Panagia, N.; Ewald, S. P.; Romaniello, M. +2 more
HST-WFPC2 optical and ultraviolet imaging observations of the young double cluster NGC 1850 in the LMC are presented. The main cluster, NGC 1850A, is a globular-like cluster and has an age of 50+/-10 Myr, while the subcluster, NGC 1850B, which is more loosely distributed, is very young at 4.3 +/- 0.9 Myr. Its young age is confirmed by the detectio…
Hubble Space Telescope Goddard High-Resolution Spectrograph H 2 Rotational Spectra of Jupiter's Aurora
Vidal-Madjar, Alfred; Clarke, John T.; Ben Jaffel, Lotfi +6 more
We have observed the emission spectrum from Jupiter's north auroral atmosphere with 0.57 A spectral resolution over 1204-1241 A. Bright emissions have been detected from 50 deg to 60 deg latitude at locations consistent with 6 to 30 R J auroral ovals, with much fainter emissions away form the auroral ovals. The emission spectrum is well…