Search Publications
Missions
Journals
Publication Years
CELIAS - Charge, Element and Isotope Analysis System for SOHO
Livi, S.; Hsieh, K. C.; Wurz, P. +30 more
The CELIAS experiment on SOHO is designed to measure the mass, ionic charge and energy of the low and high speed solar wind, of suprathermal ions, and of low energy flare particles. Through analysis of the elemental and isotopic abundances, the ionic charge state, and the velocity distributions of ions originating in the solar atmosphere, the inve…
WFPC2 Studies of the Crab Nebula. I. HST and ROSAT Imaging of the Synchrotron Nebula
Casertano, Stefano; Ballester, Gilda E.; Crisp, David +18 more
We present images of the Crab synchrotron nebula obtained with the Wide Field and Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope. These data are compared with ROSAT HRI images, and with 0."5 resolution Canada-France-Hawaii Telescope (CFHT) images previously published by van den Bergh & Pritchet (1989). These data strengthen the…
Dust in the Cores of Early-Type Galaxies
Franx, M.; van Dokkum, P. G.
The dust properties of all early-type galaxies imaged with the Planetary Camera of the Hubble Space Telescope in cycles I-III are examined. Dust is detected in 31 out of 64 galaxies, although the sample is biased against the detection of dust. From the distribution of observed axis ratios of the dust features it is inferred that 78% +/- 16% of ear…
Canada-France Redshift Survey: Hubble Space Telescope Imaging of High-Redshift Field Galaxies
Crampton, David; Lilly, S. J.; Hammer, F. +3 more
Hubble Space Telescope B and I images are presented of 32 galaxies with secure redshifts in the range 0.5 < z < 1.2 from the Canada-France Redshift Survey, a complete sample of galaxies with 17.5 <= IAB <= 22.5. These galaxies exhibit the same range of morphological types as seen locally, i.e., ellipticals, spirals, and irregulars. The…
The Central Region in M100: Observations and Modeling
Knapen, J. H.; de Jong, R. S.; Beckman, J. E. +2 more
We present new high-resolution observations of the central region in the late-type spiral galaxy M100 (NGC 4321) supplemented by three-dimensional numerical modeling of stellar and gas dynamics, including star formation (SF). Near-infrared imaging has revealed a small bulge of 4" effective diameter; a 60" radial length stellar bar of moderate stre…
Faintest Galaxy Morphologies From HST WFPC2 Imaging of the Hawaii Survey Fields
Cowie, Lennox L.; Hu, Esther M.; Songaila, Antoinette
We present very deep HST WFPC2 images in the F814W filter of two Hawaii Survey fields, SSA13 and SSA22. Using these data with previous ground- based imaging and spectroscopy, we compare the colors, star-forming properties, and morphologies of the faintest galaxies with a reference sample of bright nearby galaxies and analyze the changes in field g…
Ultraviolet Radiation from Evolved Stellar Populations. II. The Ultraviolet Upturn Phenomenon in Elliptical Galaxies
O'Connell, Robert W.; Dorman, Ben; Rood, Robert T.
We discuss the far-ultraviolet upturn phenomenon (UVX) observed in elliptical galaxies and spiral galaxy bulges. Our premise is the the UV radiation from these systems emanates primarily from extreme horizontal branch (EHB) stars and their progeny. Such objects have zero-age horizontal branch envelope masses M_env_^0^<~0.05 M_sun_. Local exampl…
Three-dimensional magnetic reconnection and the magnetic topology of coronal mass ejection events
Hesse, M.; Gosling, J. T.; Birn, J.
Measurements of suprathermal electron fluxes in the solar wind indicate that field lines within coronal mass ejections, CMEs, near and beyond 1 AU are normally connected to the Sun at both ends. However, on occasion some field lines embedded deep within CMEs appear to be connected to the Sun at only one end. Here we propose an explanation for how …
Deuterium and the Local Interstellar Medium Properties for the Procyon and Capella Lines of Sight
Ayres, Thomas R.; Savage, Blair D.; Brown, Alexander +3 more
We present Goddard High-Resolution Spectrograph observations of the interstellar H I and D I Lyα lines and the Mg II and Fe II resonance lines formed along the lines of sight toward the nearby stars Procyon (3.5 pc, l = 214°, b = 13°) and Capella (12.5 pc, l = 163°, b = 5°). New observations of Capella were obtained at orbital phase 0.80, when the…
The Intermediate Stellar Mass Population in R136 Determined from Hubble Space Telescope Planetary Camera 2 Images
Holtzman, Jon A.; Lynds, Roger; Light, Robert M. +3 more
We have analyzed Hubble Space Telescope (HST) images of the compact, luminous star cluster R136 in the LMC that were taken with the refurbished HST and new Wide Field/Planetary Camera. These images allow us to examine the stellar population in a region of unusually intense star formation at a scale of 0.01 pc. We have detected stars to 23.5 in F55…