Search Publications
Hubble Space Telescope Mapping of the Orion Nebula. I. A Survey of Stars and Compact Objects
O'Dell, C. R.; Wong, Kwan
We report on a survey of the brightest portions of the Orion Nebula made with the Wide Field Planetary Camera 2 of the Hubble Space Telescope. Fifteen pointings were made, each employing interference filters isolating the principal emission lines of H I, [N II], and [O III] and another isolating an interval similar to the V bandpass. A careful sur…
Multiwavelength Observations of Short-Timescale Variability in NGC 4151. IV. Analysis of Multiwavelength Continuum Variability
Shull, J. M.; Glass, I. S.; Malkan, M. A. +88 more
This paper combines data from the three preceding papers in order to analyze the multi-wave-band variability and spectral energy distribution of the Seyfert I galaxy NGC 4151 during the 1993 December monitoring campaign. The source, which was near its peak historical brightness, showed strong, correlated variability at X-ray, ultraviolet, and opti…
Far-Ultraviolet Imaging of Jupiter's Aurora and the lo "Footprint"
Casertano, Stefano; Ballester, Gilda E.; Feldman, Paul D. +18 more
Far-ultraviolet images of Jupiter from the Hubble Space Telescope Wide Field Planetary Camera 2 reveal polar auroral emissions at 300 kilometer resolution and three times higher sensitivity than previously achieved. Persistent features include a main oval containing most of the emission and magnetically connected to the middle magnetosphere, diffu…
Hubble Space Telescope Observations of Candidate Young Globular Clusters and Stellar Associations in the Recent Merger Remnant NGC 3921
Whitmore, Bradley C.; Fall, S. Michael; Miller, Bryan W. +1 more
New, high-resolution images of NGC 3921 obtained with the Wide Field and Planetary Camera 2 of the refurbished HST are presented. NGC 3921 is the remnant of two merged disk galaxies and thought to be a 0.7+/-0.3 Gyr old protoelliptical. A search for star clusters has yielded 102 candidate globular clusters (GC) and 49 separate, more extended stell…
An ISO SWS view of interstellar ices: first results.
Prusti, T.; de Graauw, T.; van Dishoeck, E. F. +7 more
The availability of SWS data from the Infrared Space Observatory is a landmark in the study of interstellar ices. This paper presents a brief review of what was known prior to the launch of ISO, and attempts a synthesis of what has been learned from the ISO observations available to date. Key areas of uncertainty are identified to provide a basis …
Projected Rotational Velocities of O-Type Stars
Penny, Laura R.
I present an homogeneous set of projected rotational velocities for 177 O stars based upon lUE high- dispersion spectra of the UV photo spheric lines. The line widths are estimated by cross-correlating each spectrum with the spectrum of a narrow-lined O star (HD 34078), and the widths of the cross-correlation functions are transformed to projected…
Evidence for an Io plasma torus influence on high-latitude Jovian radio emission
Brown, M. E.; Kaiser, M. L.; Desch, M. D.
We report the discovery with the Ulysses unified radio and plasma wave (URAP) instrument of features in the Jovian hectometer (HOM) wavelength radio emission spectrum which recur with a period about 2-4% longer than the Jovian System III rotation period. We conclude that the auroral HOM emissions are periodically blocked from ``view'' by regions i…
Adaptive Optics Near-Infrared Imaging of R136 in 30 Doradus: The Stellar Population of a Nearby Starburst
Genzel, R.; Quirrenbach, A.; Bertoldi, F. +6 more
We report 0".15 resolution near-infrared (NIR) imaging of R136, the central region of 30 Doradus in the large Magellanic Cloud. Our 12".8 x 12".8 images were recorded with the MPE camera SHARP II at the 3.6 m ESO telescope, using the adaptive optics system COME ON+. The high spatial resolution and sensitivity (20th magnitude in K) of our observati…
Helioseismic Constraints on the Gradient of Angular Velocity at the Base of the Solar Convection Zone
Kosovichev, A. G.
The layer of transition from the nearly rigid rotation of the radiative interior to the latitudinal differential rotation of the convection zone plays a significant role in the internal dynamics of the Sun. Using rotational splitting coefficients of the p-mode frequencies, obtained during 1986--1990 at the Big Bear Solar Observatory, we have found…
The White Dwarf Distance to the Globular Cluster NGC 6752 (and Its Age) with the Hubble Space Telescope
Ferraro, Francesco R.; Gilmozzi, Roberto; Wesemael, F. +6 more
Deep Hubble Space Telescope (HST) observations with WFPC2 of the nearby globular cluster NGC 6752 have allowed us to obtain accurate photometry for the cluster white dwarfs (WDs). A sample of local WDs of known trigonometric parallax and mass close to that of the cluster WDs have also been observed with WFPC2. Matching the cluster and the local WD…