Search Publications
The Far-Ultraviolet Oxygen Airglow of Europa and Ganymede
Feldman, P. D.; Strobel, D. F.; McGrath, M. A. +1 more
Far-UV spectra of Europa and Ganymede, acquired by the Hubble Space Telescope Goddard High Resolution Spectrograph, indicate that, in addition to faintly reflected sunlight, both satellites emit O I 1304 Å and O I 1356 Å airglow radiation. The observed brightnesses of the reflected solar C II 1335 Å feature indicate that the disk-averaged albedos …
The Optical Properties of Gravitational Lens Galaxies as a Probe of Galaxy Structure and Evolution
Keeton, C. R.; Kochanek, C. S.; Falco, E. E.
We combine photometry and lens modeling to study the properties of 17 gravitational lens galaxies between z = 0.1 and ~1. Most of the lens galaxies are passively evolving early-type galaxies, with a few spirals. The colors, scale lengths, and ellipticities of lens galaxies are similar to those of the general population of early-type galaxies, alth…
The Problem of HIPPARCOS Distances to Open Clusters. I. Constraints from Multicolor Main-Sequence Fitting
Pinsonneault, Marc H.; Stauffer, John; Soderblom, David R. +2 more
Parallax data from the Hipparcos mission allow the direct distance to open clusters to be compared with the distance inferred from main-sequence (MS) fitting. There are surprising differences between the two distance measurements, indicating either the need for changes in the cluster compositions or reddening, underlying problems with the techniqu…
HST/WFPC2 Observations of Warm Ultraluminous Infrared Galaxies
Sanders, D. B.; Veilleux, Sylvain; Mazzarella, J. M. +2 more
We present new high-resolution B- and I-band images of a nearly complete sample of nine ``warm'' (f25/f60 > 0.2), ultraluminous infrared galaxies (ULIGs) obtained with the Wide Field Planetary Camera of the Hubble Space Telescope (HST). The HST images clearly reveal the presence of tidal tails and other features associated…
Hubble Space Telescope and VLA Observations of Seyfert 2 Galaxies: The Relationship between Radio Ejecta and the Narrow-Line Region
Simpson, Chris; Wilson, Andrew S.; Falcke, Heino
We present HST/WFPC2 images, in narrowband filters containing the [O III] λ5007 and Hα + [N II] emission lines and their adjacent continua, of a sample of seven Seyfert 2 galaxies selected because they possess either extended emission-line regions in ground-based observations or a hidden broad-line region in polarized light. Six of the galaxies ha…
Imaging of the EGG Nebula (CRL 2688) with WFPC2/HST: A History of AGB/Post--AGB Giant Branch Mass Loss
Holtzman, J. A.; Gallagher, J. S., III; Clarke, J. T. +14 more
The proto-planetary nebula, CRL 2688, has been imaged through a wideband filter centered at 606 nm (F606W) with the Wide Field Planetary Camera 2 onboard the Hubble Space Telescope. CRL 2688 is the prototypical bipolar reflection nebula in which a star is surrounded by a dense, flattened cocoon of dust seen nearly edge-on and starlight escapes pre…
Starburst-like Dust Extinction in the Small Magellanic Cloud
Gordon, Karl D.; Clayton, Geoffrey C.
The recent discovery that the ultraviolet (UV) dust extinction in starburst galaxies is similar to that found in the Small Magellanic Cloud (SMC) motivated us to reinvestigate the UV extinction found in the SMC. We have been able to improve significantly on previous studies by carefully choosing pairs of well-matched reddened and unreddened stars.…
Ultraviolet-Optical Observations of the Seyfert 2 Galaxies NGC 7130, NGC 5135, and IC 3639: Implications for the Starburst-Active Galactic Nucleus Connection
Heckman, Timothy; Leitherer, Claus; Wilson, Andrew S. +5 more
We present and discuss Hubble Space Telescope (HST) (WFPC2 and FOC) images and ultraviolet (GHRS) spectra plus ground-based optical spectra of three Seyfert 2 nuclei (NGC 7130, NGC 5135 and IC 3639). These galaxies, together with Mrk 477 (Heckman et al.), were selected on the basis of ultraviolet brightness from a bigger sample that comprises the …
SUMER Measurements of Nonthermal Motions: Constraints on Coronal Heating Mechanisms
Chae, Jongchul; Schühle, Udo; Lemaire, Philippe
We have determined nonthermal velocities in the quiet Sun at temperatures between 104 K and 2 × 106 K by measuring the widths of a number of EUV and far-ultraviolet (FUV) lines taken with SUMER on board the SOHO spacecraft. The broadenings owing to the SUMER instrument and the finite opacity in each line have been carefully e…
The Color-Magnitude Relation in CL 1358+62 at Z = 0.33: Evidence for Significant Evolution in the S0 Population
van Dokkum, Pieter G.; Franx, Marijn; Kelson, Daniel D. +3 more
We use a large, multicolor mosaic of HST WFPC2 images to measure the colors and morphologies of 194 spectroscopically confirmed members of the rich galaxy cluster CL 1358+62 at z = 0.33. We study the color-magnitude (CM) relation as a function of radius in the cluster to a limit of 4.6 arcmin from the center, equivalent to 1.6 h-15…