Candidate type II quasars from the sloan digital sky survey. I. Selection and optical properties of a sample at 0.3 < Z < 0.83

Nadia L. Zakamska; Michael A. Strauss; Julian H. Krolik; Matthew J. Collinge; Patrick B. Hall; Lei Hao; Timothy M. Heckman; Željko Ivezić; Gordon T. Richards; David J. Schlegel; Donald P. Schneider; Iskra Strateva; Daniel E. Vanden Berk; Scott F. Anderson; Jon Brinkmann

doi:10.1086/378610

Candidate type II quasars from the sloan digital sky survey. I. Selection and optical properties of a sample at 0.3 < Z < 0.83

Nadia L. Zakamska, Michael A. Strauss, Julian H. Krolik, Matthew J. Collinge, Patrick B. Hall, Lei Hao, Timothy M. Heckman, Željko Ivezić, Gordon T. Richards, David J. Schlegel, Donald P. Schneider, Iskra Strateva, Daniel E. Vanden Berk, Scott F. Anderson, Jon Brinkmann

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Abstract

Type II quasars are the long-sought luminous analogs of type 2 (narrow emission line) Seyfert galaxies, suggested by unification models of active galactic nuclei (AGNs) and postulated to account for an appreciable fraction of the cosmic hard X-ray background. We present a sample of 291 type II AGNs 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 ^-1), 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 [O III] λ5008 line luminosities in the range 3 × 10 ⁸-10 ¹⁰ L _⊙, 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.

Original language	English (US)
Pages (from-to)	2125-2144
Number of pages	20
Journal	Astronomical Journal
Volume	126
Issue number	5 1775
DOIs	https://doi.org/10.1086/378610
State	Published - Nov 2003

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/378610

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Zakamska, N. L., Strauss, M. A., Krolik, J. H., Collinge, M. J., Hall, P. B., Hao, L., Heckman, T. M., Ivezić, Ž., Richards, G. T., Schlegel, D. J., Schneider, D. P., Strateva, I., Vanden Berk, D. E., Anderson, S. F., & Brinkmann, J. (2003). Candidate type II quasars from the sloan digital sky survey. I. Selection and optical properties of a sample at 0.3 < Z < 0.83. Astronomical Journal, 126(5 1775), 2125-2144. https://doi.org/10.1086/378610

@article{9017e092c965408a9122d8ded2bfd7f1,

title = "Candidate type II quasars from the sloan digital sky survey. I. Selection and optical properties of a sample at 0.3 < Z < 0.83",

abstract = "Type II quasars are the long-sought luminous analogs of type 2 (narrow emission line) Seyfert galaxies, suggested by unification models of active galactic nuclei (AGNs) and postulated to account for an appreciable fraction of the cosmic hard X-ray background. We present a sample of 291 type II AGNs 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 -1), 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 [O III] λ5008 line luminosities in the range 3 × 10 8-10 10 L ⊙, 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.",

author = "Zakamska, {Nadia L.} and Strauss, {Michael A.} and Krolik, {Julian H.} and Collinge, {Matthew J.} and Hall, {Patrick B.} and Lei Hao and Heckman, {Timothy M.} and {\v Z}eljko Ivezi{\'c} and Richards, {Gordon T.} and Schlegel, {David J.} and Schneider, {Donald P.} and Iskra Strateva and {Vanden Berk}, {Daniel E.} and Anderson, {Scott F.} and Jon Brinkmann",

year = "2003",

month = nov,

doi = "10.1086/378610",

language = "English (US)",

volume = "126",

pages = "2125--2144",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "5 1775",

}

Zakamska, NL, Strauss, MA, Krolik, JH, Collinge, MJ, Hall, PB, Hao, L, Heckman, TM, Ivezić, Ž, Richards, GT, Schlegel, DJ, Schneider, DP, Strateva, I, Vanden Berk, DE, Anderson, SF & Brinkmann, J 2003, 'Candidate type II quasars from the sloan digital sky survey. I. Selection and optical properties of a sample at 0.3 < Z < 0.83', Astronomical Journal, vol. 126, no. 5 1775, pp. 2125-2144. https://doi.org/10.1086/378610

TY - JOUR

T1 - Candidate type II quasars from the sloan digital sky survey. I. Selection and optical properties of a sample at 0.3 < Z < 0.83

AU - Zakamska, Nadia L.

AU - Strauss, Michael A.

AU - Krolik, Julian H.

AU - Collinge, Matthew J.

AU - Hall, Patrick B.

AU - Hao, Lei

AU - Heckman, Timothy M.

AU - Ivezić, Željko

AU - Richards, Gordon T.

AU - Schlegel, David J.

AU - Schneider, Donald P.

AU - Strateva, Iskra

AU - Vanden Berk, Daniel E.

AU - Anderson, Scott F.

AU - Brinkmann, Jon

PY - 2003/11

Y1 - 2003/11

N2 - Type II quasars are the long-sought luminous analogs of type 2 (narrow emission line) Seyfert galaxies, suggested by unification models of active galactic nuclei (AGNs) and postulated to account for an appreciable fraction of the cosmic hard X-ray background. We present a sample of 291 type II AGNs 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 -1), 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 [O III] λ5008 line luminosities in the range 3 × 10 8-10 10 L ⊙, 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.

AB - Type II quasars are the long-sought luminous analogs of type 2 (narrow emission line) Seyfert galaxies, suggested by unification models of active galactic nuclei (AGNs) and postulated to account for an appreciable fraction of the cosmic hard X-ray background. We present a sample of 291 type II AGNs 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 -1), 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 [O III] λ5008 line luminosities in the range 3 × 10 8-10 10 L ⊙, 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.

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SN - 0004-6256

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JF - Astronomical Journal

IS - 5 1775

ER -

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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