Candidate Type II Quasars from the Sloan Digital Sky Survey: I. Selection and Optical Properties of a Sample at 0.3<Z<0.83

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dc.creatorZakamska, Nadia L.
dc.creatorStrauss, Michael A.
dc.creatorKrolik, Julian H.
dc.creatorCollinge, M. J.
dc.creatorHall, P. B.
dc.creatorHao, L.
dc.creatorHeckman, T. M.
dc.creatorIvezic, Z.
dc.creatorRichards, G. T.
dc.creatorSchlegel, D. J.
dc.creatorSchneider, D. P.
dc.creatorStrateva, I.
dc.creatorBerk, D. E. Vanden
dc.creatorAnderson, S. F.
dc.creatorBrinkmann, J.
dc.date2003-09-20
dc.date.accessioned2026-07-07T10:27:03Z
dc.date.available2026-07-07T10:27:03Z
dc.descriptionType II quasars are the long-sought luminous analogs of type II (narrow emission line) Seyfert galaxies, suggested by unification models of active galactic nuclei (AGN) and postulated to account for an appreciable fraction of the cosmic hard X-ray background. We present a sample of 291 type II AGN at redshifts 0.3<Z<0.83 from the spectroscopic data of the Sloan Digital Sky Survey. These objects have narrow (FWHM<2000 km/s), high equivalent width emission lines with high-ionization line ratios. We describe the selection procedure and discuss the optical properties of the sample. About 50% of the objects have [OIII] λ_air 5007 line luminosities in the range 3\times 10^8-10^10 L_Sun, comparable to those of luminous (-27<M_B<-23) quasars; this, along with other evidence, suggests that the objects in the luminous subsample are type II quasars.
dc.descriptionAccepted to AJ (November issue), 46 pages including 2 tables and 15 figures, the full version of Table 1 is available at http://www.astro.princeton.edu/~nadia/qso2.html
dc.identifierhttps://arxiv.org/abs/astro-ph/0309551
dc.identifierhttp://arxiv.org/abs/astro-ph/0309551
dc.identifierAstron.J.126:2125,2003
dc.identifierdoi:10.1086/378610
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/177043
dc.subjectAstrophysics
dc.titleCandidate Type II Quasars from the Sloan Digital Sky Survey: I. Selection and Optical Properties of a Sample at 0.3<Z<0.83
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