Search Publications
Discovery of New Objects in the Orion Nebula on HST Images: Shocks, Compact Sources, and Protoplanetary Disks
O'Dell, C. R.; Wen, Zheng; Hu, Xihai
We have reduced and analyzed a set of narrow-band HST images of a portion of M42 south of the Trapezium. Many new emission-line sources were found, some quite long but so narrow that they are not seen on ground-based images. These include thin shells which are high-ionization shocks. The structure around Orion HH 3 is resolved into multiple compon…
Hubble Space Telescope Discovery of Candidate Young Globular Clusters in the Merger Remnant NGC 7252
Robert, Carmelle; Leitherer, Claus; Whitmore, Bradley C. +2 more
New, high-resolution images of the central region of NGC 7252 obtained with the Planetary Camera of the Hubble Space Telescope are presented. NGC 7252 (sometimes referred to as the "Atoms-for-Peace" Galaxy) is a prototypical example of a remnant of two merged disk galaxies. Our most striking result is the discovery of a population of about 40 blue…
Goddard High-Resolution Spectrograph Observations of the Local Interstellar Medium and the Deuterium/Hydrogen Ratio along the Line of Sight toward Capella
Ayres, Thomas R.; Savage, Blair D.; Brown, Alexander +6 more
HST Goddard High-Resolution Spectrograph observations of the 1216, 2600, and 2800 A spectral regions are analyzed for the spectroscopic binary system Capella, obtained at orbital phase 0.26 with 3.27-3.57 km/s resolution and high SNR. The column densities of H I, D I, Mg II, and Fe II for the local interstellar medium along this 12.5 pc line of si…
The Hubble Space Telescope Quasar Absorption Line Key Project. I. First Observational Results, Including Lyman-Alpha and Lyman-Limit Systems
Turnshek, David A.; Schneider, Donald P.; Savage, Blair D. +9 more
We present spectra for a total of 37 quasars with small and moderate redshifts; the quasars were observed with the Faint Object Spectrograph of the Hubble Space Telescope. The spectra are obtained either at a resolution of R = 1300 (hereafter "higher resolution") or a resolution of r = 180 (hereafter "lower resolution"). We report new higher resol…
Early-Type Galaxies, Dark Halos, and Gravitational Lensing Statistics
Maoz, Dan; Rix, Hans-Walter
We present calculations of the expected statistics of gravitational lensing of quasars in the Hubble Space Telescope snapshot survey. We first model early-type (elliptical and SO) galaxies using their observed surface brightness profiles and dynamically inferred mass-to-light ratios. Our work improves upon previous calculations, which have general…
Composition of Interstellar Clouds in the Disk and Halo. I. HD 93521
Fitzpatrick, Edward L.; Spitzer, Lyman, Jr.
Interstellar column densities of Fe, S, Si, Mn, and Mg in their dominant ionization state, as well as of C(+) and S(2+), are presently derived from analyses of HST UV observations of the Galactic halo star HD 93521. Ratios of column densities for the dominant species yield approximations of the logarithmic depletion D(X) in the warm, primarily neu…
Planetary Camera Observations of the Double Nucleus of M31
Holtzman, J. A.; Faber, S. M.; Ewald, S. P. +13 more
V- and I-band HST Planetary Camera images of the great spiral galaxy in Andromeda, M31, show that its inner nucleus consists of two components separated by 0.49". The outer isophotes of the nucleus at 1.4" < r < 3.0" are elongated, but are concentric with the M31 bulge. The nuclear component with the lower surface brightness, P2, is also coi…
SN 1992A: Ultraviolet and Optical Studies Based on HST, IUE, and CTIO Observations
Suntzeff, N. B.; Fransson, Claes; Challis, Peter M. +18 more
The Type Ia supernova SN 1992A in the 50 galaxy NGC 1380 was observed as a target of opportunity by the International Ultraviolet Explorer (IUE) and with great alacrity by the Hubble Space Telescope (HST). Here we present the HST and lUE spectra and photometry that we obtained, as well as optical spectra obtained at the Cerro Tololo Inter-American…
High Resolution Imaging of Galaxy Cores
Boksenberg, A.; Barbieri, C.; Weigelt, G. +17 more
Surface photometry data obtained with the Faint Object Camera of the Hubble Space Telescope in the cores of ten galaxies is presented. The major results are: (i) none of the galaxies show truly "isothermal" cores, (ii) galaxies with nuclear activity show very similar light profiles, (iii) all objects show central mass densities > 10^3^M_sun_ pc…
A large nuclear accretion disk in the active galaxy NGC4261
O'Connell, Robert W.; Ferrarese, Laura; Ford, Holland C. +2 more
THE powerful emissions from the nuclei of active galaxies and quasars are thought to arise from the accretion of matter onto a massive black hole. Angular momentum will prevent matter from falling directly onto the central mass; instead, an 'accretion disk' should form, within which the gravitationally bound material will lose angular momentum and…