Candidate Type II Quasars from the Sloan Digital Sky Survey. I. Selection and Optical Properties of a Sample at 0.3 < Z < 0.83
@article{Zakamska2003CandidateTI, 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}, author={Nadia L. Zakamska and Michael A. Strauss and Julian H. Krolik and Matthew J. Collinge and Patrick B. Hall and Lei Hao and Timothy M. Heckman and Željko Ivezi{\'c} and Gordon T. Richards and David J. Schlegel and Donald P. Schneider and Iskra V. Strateva and Daniel E. vanden Berk and Scott F. Anderson and Jonathan Brinkmann}, journal={The Astronomical Journal}, year={2003}, volume={126}, pages={2125 - 2144} }
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…
Figures and Tables from this paper
268 Citations
Candidate Type II Quasars from the Sloan Digital Sky Survey. II. From Radio to X-Rays
- Physics
- 2004
Type II quasars are luminous active galactic nuclei (AGNs) whose central engines and broad-line regions are obscured by intervening material; such objects only recently have been discovered in…
Candidate type II quasars at 2 < z < 4.3 in the Sloan Digital Sky Survey III
- Physics
- 2013
At low redshifts, dust-obscured quasars often have strong yet narrow permitted lines in the rest-frame optical and ultraviolet, excited by the central active nucleus, earning the designation Type II…
Optical Spectroscopy and X-Ray Detections of a Sample of Quasars and Active Galactic Nuclei Selected in the Mid-Infrared from Two Spitzer Space Telescope Wide-Area Surveys
- Physics
- 2006
We present optical spectroscopy of a sample of 77 luminous active galactic nuclei (AGNs) and quasars selected on the basis of their mid-infrared colors. Our objects are selected from the Spitzer…
Type II Quasars from the Sloan Digital Sky Survey. V. Imaging Host Galaxies with the Hubble Space Telescope
- Physics
- 2005
Type II quasars are luminous active galactic nuclei (AGNs) whose centers are obscured by large amounts of gas and dust. In this paper we present three-band Hubble Space Telescope images of nine type…
SPACE DENSITY OF OPTICALLY SELECTED TYPE 2 QUASARS
- Physics
- 2008
Type 2 quasars are luminous active galactic nuclei whose central regions are obscured by large amounts of gas and dust. In this paper, we present a catalog of type 2 quasars from the Sloan Digital…
Spectroscopic identification of type 2 quasars at z < 1 in SDSS-III/BOSS
- Physics
- 2016
The physics and demographics of type 2 quasars remain poorly understood, and new samples of such objects selected in a variety of ways can give insight into their physical properties, evolution, and…
The quest for Type 2 quasars: Chandra observations of luminous obscured quasars in the Sloan Digital Sky Survey
- Physics
- 2006
We report on new Chandra exploratory observations of six candidate Type 2 quasars at z = 0.49-0.73 selected among the most [O III] luminous emitters from the Sloan Digital Sky Survey (SDSS). Under…
HOST GALAXIES OF LUMINOUS TYPE 2 QUASARS AT z ∼ 0.5
- Physics
- 2009
We present deep Gemini GMOS optical spectroscopy of nine luminous quasars at redshifts z ∼ 0.5, drawn from the Sloan Digital Sky Survey type 2 quasar sample. Our targets were selected to have high…
NuSTAR REVEALS EXTREME ABSORPTION IN z < 0.5 TYPE 2 QUASARS
- Physics
- 2015
The intrinsic column density (NH) distribution of quasars is poorly known. At the high obscuration end of the quasar population and for redshifts z < 1, the X-ray spectra can only be reliably…
NEAR-INFRARED SPECTRA AND INTRINSIC LUMINOSITIES OF CANDIDATE TYPE II QUASARS AT 2 < z < 3.4
- Physics
- 2014
We present JHK near-infrared (NIR) spectroscopy of 25 candidate Type II quasars selected from the Sloan Digital Sky Survey (SDSS), using Triplespec on the Apache Point Observatory 3.5 m telescope,…
References
SHOWING 1-10 OF 82 REFERENCES
Chandra Detection of a Type II Quasar at z = 3.288
- Physics
- 2001
We report on observations of a type II quasar at redshift z = 3.288, identified as a hard X-ray source in a 185 ks observation with the Chandra X-Ray Observatory and as a high-redshift photometric…
The Population of Faint Optically Selected Active Galactic Nuclei at z ~ 3
- Physics
- 2002
We discuss a sample of 29 active galactic nuclei (AGNs) (16 narrow-lined and 13 broad-lined) discovered in a spectroscopic survey of ~1000 star-forming Lyman break galaxies (LBGs) at z ≃ 3. Reaching…
A Large, Uniform Sample of X-Ray-emitting AGNs: Selection Approach and an Initial Catalog from the ROSAT All-Sky and Sloan Digital Sky Surveys
- Physics
- 2003
Many open questions in X-ray astronomy are limited by the relatively small number of objects in uniform optically identified and observed samples, especially when rare subclasses are considered or…
OBSERVATIONS OF A COMPLETE SAMPLE OF EMISSION-LINE GALAXIES
- Physics
- 1986
Optical spectroscopic and broad-band B and V imaging observations have been obtained for all 172 emission-line galaxy (ELG) candidates in Lists IV and V of the University of Michigan Curtis Schmidt…
Colors of 2625 Quasars at 0 < z < 5 Measured in the Sloan Digital Sky Survey Photometric System
- Physics
- 2000
We present an empirical investigation of the colors of quasars in the Sloan Digital Sky Survey (SDSS) photometric system. The sample studied includes 2625 quasars with SDSS photometry: 1759 quasars…
Double-peaked Low-Ionization Emission Lines in Active Galactic Nuclei
- Physics
- 2003
We present a new sample of 116 double-peaked Balmer line active galactic nuclei (AGNs) selected from the Sloan Digital Sky Survey. Double-peaked emission lines are believed to originate in the…
Optical and Radio Properties of Extragalactic Sources Observed by the FIRST Survey and the Sloan Digital Sky Survey
- Physics
- 2002
We discuss the optical and radio properties of ∼30,000 FIRST (radio, 20 cm, sensitive to 1 mJy) sources positionally associated within 1.″5 with a Sloan Digital Sky Survey (SDSS) (optical, sensitive…
A Classic Type 2 QSO
- Physics
- 2002
In the Chandra Deep Field-South 1 Ms exposure, we have found, at redshift 3.700 ± 0.005, the most distant type 2 active galactic nucleus ever detected. It is the source with the hardest X-ray…
Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Quasar Sample
- Physics
- 2002
We describe the algorithm for selecting quasar candidates for optical spectroscopy in the Sloan Digital Sky Survey. Quasar candidates are selected via their nonstellar colors in ugriz broadband…
A Search for “Dwarf'' Seyfert Nuclei. V. Demographics of Nuclear Activity in Nearby Galaxies
- Physics
- 1997
We use the sample of emission-line nuclei derived from a recently completed optical spectroscopic survey of nearby galaxies to quantify the incidence of local (z ≈ 0) nuclear activity. Particular…