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EIT: Extreme-Ultraviolet Imaging Telescope for the SOHO Mission
Michels, D. J.; Gurman, J. B.; Delaboudinière, J. -P. +25 more
The Extreme-ultraviolet Imaging Telescope (EIT) will provide wide-field images of the corona and transition region on the solar disc and up to 1.5 R⊙ above the solar limb. Its normal incidence multilayer-coated optics will select spectral emission lines from Fe IX (171 å), Fe XII (195 å), Fe XV (284 å), and He II (304 å) to provide sensitive tempe…
The SOHO Mission: an Overview
Domingo, V.; Fleck, B.; Poland, A. I.
The Solar and Heliospheric Observatory (SOHO) is a space mission that forms part of the Solar-Terrestrial Science Program (STSP), developed in a collaborative effort by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). The STSP constitutes the first "cornerstone" of ESA's long-term programme known as "Sp…
SUMER - Solar Ultraviolet Measurements of Emitted Radiation
Vial, J. -C.; Grewing, M.; Wilhelm, K. +13 more
The instrument SUMER - Solar Ultraviolet Measurements of Emitted Radiation is designed to investigate structures and associated dynamical processes occurring in the solar atmosphere, from the chromosphere through the transition region to the inner corona, over a temperature range from 104 to 2 × 106K and above. These observat…
The Coronal Diagnostic Spectrometer for the Solar and Heliospheric Observatory
Mason, H. E.; Harrison, R. A.; Fludra, A. +36 more
The Coronal Diagnostic Spectrometer is designed to probe the solar atmosphere through the detection of spectral emission lines in the extreme ultraviolet wavelength range 150 - 800 å. By observing the intensities of selected lines and line profiles, we may derive temperature, density, flow and abundance information for the plasmas in the solar atm…
The Centers of Early-Type Galaxies with HST.I.An Observational Survey
Faber, S. M.; Dressler, A.; Byun, Y. -I. +6 more
We have obtained V-band images of 45 nearby elliptical galaxies and bulges using the original Planetary Camera of the Hubble Space Telescope. The majority of the sample is at distances of 10-20 Mpc. This represents a substantial increase in the number of galaxies that have been studied at a resolution of a few parsecs. At this resolution, many gal…
Hubble Space Telescope Observations of Young Star Clusters in NGC 4038/4039, "The Antennae" Galaxies
Whitmore, Bradley C.; Schweizer, Francois
New, high-resolution images of the disks of NGC 4038/4039 obtained with the Wide Field Camera of the Hubble Space Telescope (HST) are presented. NGC 4038/4039, nicknamed "The Antennae," is a prototypical example of a pair of colliding galaxies believed to be at an early stage of a merger. Down to the limiting magnitude of V~23 mag, the HST images …
Starbursts and Star Clusters in the Ultraviolet
Leitherer, C.; Garnett, D. R.; Heckman, T. M. +3 more
We present ultraviolet (UV) images of nine starburst galaxies obtained with the Hubble Space Telescope using the Faint Object Camera. The galaxies range in morphology from blue compact dwarfs to ultraluminous merging far-infrared galaxies. Our data combined with new and archival UV spectroscopy and far-infrared fluxes allow us to dissect the anato…
The Ultraviolet Coronagraph Spectrometer for the Solar and Heliospheric Observatory
Livi, S.; Romoli, M.; Geiss, J. +37 more
The SOHO Ultraviolet Coronagraph Spectrometer (UVCS/SOHO) is composed of three reflecting telescopes with external and internal occultation and a spectrometer assembly consisting of two toric grating spectrometers and a visible light polarimeter. The purpose of the UVCS instrument is to provide a body of data that can be used to address a broad ra…
The IUE Survey for Damped Lyman- alpha and Lyman-Limit Absorption Systems: Evolution of the Gaseous Content of the Universe
Turnshek, David A.; Lanzetta, Kenneth M.; Wolfe, Arthur M.
We present a spectroscopic survey for moderate-redshift absorption features from damped Lyα and Lyman- limit absorption systems. The survey is based on a set of optimally extracted and co-added International Ultraviolet Explorer spectra of QSOs, BL Lac objects, and Seyfert galaxies. Results of this survey are combined with those of previous survey…
Software for the Analysis of Emission Line Nebulae
Shaw, Richard A.; Dufour, Reginald J.
A set of software tools has been developed for the IRAF/STSDAS environment to derive the physical conditions in a low-density (nebular) gas given appropriate diagnostic emission line ratios; and lien emissivities given appropriate emission line fluxes, the electron temperature (T_e) and density (N_e). The package is based on the five-level program…