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Title: First results from the Goddard High-Resolution Spectrograph - The Galactic halo and the Ly-alpha forest at low redshift in 3C 273

Abstract

Results of initial spectroscopy using the Goddard High-Resolution Spectrograph and the Hubble Space Telescope on the bright low-redshift quasar 3C 273 are presented. Absorption lines produced by gas in the disk and halo of the Galaxy from numerous neutral and weakly ionized atoms and also from highly ionized atoms are detected. The detection of N v provides additional strong support for the existence of gas with T about 200,000 K at large distances away from the disk of the Galaxy. Ten absorption lines with EW greater than 50 mA, and four possible lines with EW between 25 and 50 mA, are also found in the region between 1235 and 1406 A. These cannot be identified with any lines in the galactic interstellar medium and must therefore all be Ly-alpha systems at very low redshifts. This number of lines is 5-10 times larger than expected from a simple extrapolation of the high-redshift evolution derived from ground-based observations and is consistent with no evolution in cloud properties since z = 2. 28 refs.

Authors:
; ; ;  [1]
  1. (Observatories of the Carnegie Institution of Washington, Pasadena, CA (United States) Wisconsin Univ., Madison (United States) Space Telescope Science Inst., Baltimore, MD (United States))
Publication Date:
OSTI Identifier:
5157137
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal; (United States)
Additional Journal Information:
Journal Volume: 377; Other Information: L21-L24; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; QUASARS; SPECTROSCOPY; ABSORPTION SPECTRA; COSMIC GASES; COSMOLOGY; INTERSTELLAR SPACE; LYMAN LINES; MILKY WAY; RED SHIFT; ULTRAVIOLET SPECTRA; COSMIC RADIO SOURCES; FLUIDS; GALAXIES; GASES; SPACE; SPECTRA; 640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources

Citation Formats

Morris, S.L., Weymann, R.J., Savage, B.D., and Gilliland, R.L. First results from the Goddard High-Resolution Spectrograph - The Galactic halo and the Ly-alpha forest at low redshift in 3C 273. United States: N. p., 1991. Web. doi:10.1086/186107.
Morris, S.L., Weymann, R.J., Savage, B.D., & Gilliland, R.L. First results from the Goddard High-Resolution Spectrograph - The Galactic halo and the Ly-alpha forest at low redshift in 3C 273. United States. doi:10.1086/186107.
Morris, S.L., Weymann, R.J., Savage, B.D., and Gilliland, R.L. Thu . "First results from the Goddard High-Resolution Spectrograph - The Galactic halo and the Ly-alpha forest at low redshift in 3C 273". United States. doi:10.1086/186107.
@article{osti_5157137,
title = {First results from the Goddard High-Resolution Spectrograph - The Galactic halo and the Ly-alpha forest at low redshift in 3C 273},
author = {Morris, S.L. and Weymann, R.J. and Savage, B.D. and Gilliland, R.L.},
abstractNote = {Results of initial spectroscopy using the Goddard High-Resolution Spectrograph and the Hubble Space Telescope on the bright low-redshift quasar 3C 273 are presented. Absorption lines produced by gas in the disk and halo of the Galaxy from numerous neutral and weakly ionized atoms and also from highly ionized atoms are detected. The detection of N v provides additional strong support for the existence of gas with T about 200,000 K at large distances away from the disk of the Galaxy. Ten absorption lines with EW greater than 50 mA, and four possible lines with EW between 25 and 50 mA, are also found in the region between 1235 and 1406 A. These cannot be identified with any lines in the galactic interstellar medium and must therefore all be Ly-alpha systems at very low redshifts. This number of lines is 5-10 times larger than expected from a simple extrapolation of the high-redshift evolution derived from ground-based observations and is consistent with no evolution in cloud properties since z = 2. 28 refs.},
doi = {10.1086/186107},
journal = {Astrophysical Journal; (United States)},
issn = {0004-637X},
number = ,
volume = 377,
place = {United States},
year = {1991},
month = {8}
}