Search Publications
Global Oscillations at Low Frequency from the SOHO Mission (GOLF)
Damé, L.; García, R. A.; Pallé, P. L. +28 more
The GOLF experiment on the SOHO mission aims to study the internal structure of the sun by measuring the spectrum of global oscillations in the frequency range 10−7 to 10−2 Hz. Bothp andg mode oscillations will be investigated, with the emphasis on the low order long period waves which penetrate the solar core. The instrument…
The Heliospheric Magnetic Field Over the South Polar Region of the Sun
Balogh, A.; Tsurutani, B. T.; Horbury, T. S. +3 more
Magnetic field measurements from the Ulysses space mission over the south polar regions of the sun showed that the structure and properties of the three-dimensional heliosphere were determined by the fast solar wind flow and magnetic fields from the large coronal holes in the polar regions of the sun. This conclusion applies at the current, minimu…
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 …