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The Hubble Space Telescope quasar absorption line key project. I - First observational results, including Lyman-alpha and Lyman-limit systems
Bahcall, John N.; Bergeron, Jacqueline; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Sargent, W. L. W.; Savage, Blair D.; Schneider, Donald P.; Turnshek, David A.; Weymann, Ray J.; Wolfe, Arthur M.
AA(Inst. for Advanced Study, Princeton, NJ), AB(CNRS, Inst. d'Astrophysique, Paris, France), AC(Royal Greenwich Observatory, Cambridge, United Kingdom), AD(Space Telescope Science Inst., Baltimore, MD), AE(Inst. for Advanced Study, Princeton, NJ), AF(Inst. for Advanced Study, Princeton, NJ), AG(California Inst. of Technology, Pasadena), AH(Wisconsin Univ., Madison), AI(Inst. for Advanced Study, Princeton, NJ), AJ(Pittsburgh Univ., PA)
Astrophysical Journal Supplement Series (ISSN 0067-0049), vol. 87, no. 1, p. 1-43. (ApJS Homepage)
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NASA/STI Keywords:
Absorption Spectra, Hubble Space Telescope, Lyman Alpha Radiation, Quasars, Emission Spectra, Maximum Likelihood Estimates, Red Shift, Ultraviolet Spectra
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Spectra are presented for 37 quasars with small and moderate redshifts; the quasars were observed with the Faint Object Spectrograph of the HST. New higher resolution measurements of the absorption lines in the UV spectra of 11 quasars with emission-line redshifts that lie between 0.3 and 1.0 are reported. Calibrated spectra and continuum fits are shown for each object. A total of 104 extragalactic Ly-alpha systems are identified, nine of which are found at the same redshifts as metal-line systems. The local number density of Ly-alpha systems with rest equivalent widths larger than 0.32 A and without detected metal lines is about 15.1 +/- 4.3 Ly-alpha systems per unit redshift with gamma = 0.30 +/- 0.62 and W* = 0.22 +/- 0.02 A. A total of 10 Lyman-limit systems with an optical depth greater than 0.4 are identified. The paucity of damped Ly-alpha lines at small and moderate redshifts shows that the number density of damped absorption systems decreases with decreasing redshift.

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Part  3     Part  1     Part  2     Part  4     Part 11     Part  6     Part  8     Part 10     Part  5     Part 12     Part  7     Part 13     Part 15     Part 14     Part 16    

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