Spectroscopic CCD surveys for quasars at large redshift. V. The Palomar Scan Grism Survey catalog

D. P. Schneider, Maarten Schmidt, J. E. Gunn

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This paper presents the catalog of objects found in the Palomar Scan Grism Survey (PSGS). The survey consists of eight narrow (≈8′.5 wide) strips of sky; the total effective area is 1.10 deg2. Low-resolution slitless spectra, covering the wavelength range 4400-7500 Å, were obtained for approximately 97,000 objects. The wavelength- and flux-calibrated spectra were searched for emission lines with an automatic software algorithm. A total of 192 emission features in the grism data satisfied our signal-to-noise ratio and equivalent-width selection criteria; subsequent slit spectroscopy of the candidates confirmed the existence of 111 lines (96 different objects). Six groups of emission lines were detected in the survey: Lyα + N V, C IV, C III], Mg II, Hβ + [O III], and Hα + [S II]. Slightly more than half of the confirmed lines are low-redshift (z < 0.45) emission-line galaxies; nine objects are high-redshift quasars (z > 2.7) detected via their Lyα + N V emission lines. Two unusual emission-line objects were found as part of the survey; one is a late-type star (M9.5) with very strong Balmer emission, the other is an unresolved source with numerous broad emission lines and a strong absorption line.

Original languageEnglish (US)
Pages (from-to)40-55
Number of pages16
JournalAstronomical Journal
Issue number1
StatePublished - Jan 1999

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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