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The Ultraviolet-To-Mid-Infrared Spectral Energy Distribution of Weak Emission Line Quasars

Description: This article presents Spitzer Space Telescope photometry of 18 Sloan Digital Sky Survey quasars which have weak or undetectable high-ionization emission lines in their rest-frame ultraviolet spectra.
Date: September 23, 2011
Creator: Lane, Ryan A.; Shemmer, Ohad; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Anderson, Scott F.; Brandt, William Nielsen et al.
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Partner: UNT College of Arts and Sciences
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Unexpected Structures for Intercalation of Sodium in Epitaxial Graphene-SiC Interfaces

Description: In this paper, the authors show using scanning tunneling microscopy, spectroscopy, and ab initio calculations that several intercalation structures exist for Na in epitaxial graphene on SiC(0001). Intercalation takes place at room temperature and Na electron-dopes the graphene. It intercalates in-between single-layer graphene and the carbon-rich interfacial layer. It also penetrates beneath the interfacial layer and decouples it to form a second graphene layer. This decoupling is accelerated by… more
Date: February 2012
Creator: Sandin, Andreas; Jayasekera, Thushari; Rowe, J. E.; Kim, Ki Wook; Buongiorno Nardelli, Marco & Dougherty, Daniel B.
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Partner: UNT College of Arts and Sciences
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Variability-Selected Low-Luminosity Active Galactic Nuclei in the 4 Ms Chandra Deep Field-South

Description: This article demonstrates that the observed variability cannot be explained by X-ray Binary populations or ultraluminous X-ray sources, so the variability is most likely caused by accretion onto a supermassive black hole.
Date: January 18, 2012
Creator: Young, Monica; Brandt, William Nielsen; Xue, Yongquan; Alexander, David M.; Bauer, Franz E.; Lehmer, Bret et al.
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Partner: UNT College of Arts and Sciences
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Weak Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-Line Regions?

Description: This article presents Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines.
Date: September 8, 2010
Creator: Shemmer, Ohad; Trakhtenbrot, Benny; Anderson, Scott F.; Brandt, William Nielsen; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui et al.
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Partner: UNT College of Arts and Sciences
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X-Ray and Multiwavelength Insights into the Nature of Weak Emission-Line Quasars at Low Redshift

Description: This article reports on the X-ray and multiwavelength properties of 11 radio-quiet quasars with weak or no emission lines identified by the Sloan Digital Sky Survey with redshift.
Date: December 9, 2011
Creator: Wu, Jianfeng; Brandt, William Nielsen; Anderson, Scott F.; Diamond-Stanic, Aleksandar M.; Hall, Patrick B.; Plotkin, Richard M. et al.
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Partner: UNT College of Arts and Sciences
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X-Ray Insights Into the Nature of Weak Emission-Line Quasars at High Redshift

Description: This article presents Chandra observations of nine high-redshift quasars discovered by the Sloan Digital Sky Survey with weak or undetectable high-ionization emission lines in their UV spectra.
Date: February 8, 2009
Creator: Shemmer, Ohad; Brandt, William Nielsen; Anderson, Scott F.; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Richards, Gordon T. et al.
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Partner: UNT College of Arts and Sciences
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The X-Ray Properties of the Most Luminous Quasars From the Sloan Digital Sky Survey

Description: This article studies the X-ray properties of a representative sample of 59 of the most optically luminous quasars in the universe spanning a redshift range of z ≈ 1.5-4.5.
Date: May 18, 2007
Creator: Just, Dennis W.; Brandt, William Nielsen; Shemmer, Ohad; Steffen, Aaron; Schneider, Donald P.; Chartas, George et al.
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Partner: UNT College of Arts and Sciences
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The X-Ray Properties of the Optically Brightest Mini-Bal Quasars from the Sloan Digital Sky Survey

Description: This article compiles a sample of 14 of the optically brightest radio-quiet quasars in the Sloan Digital Sky Survey Data Release 5 quasar catalog that have mini-broad absorption lines present in their spectra.
Date: September 12, 2010
Creator: Wu, Jianfeng; Brandt, William Nielsen; Comins, M.L.; Gibson, Robert R.; Shemmer, Ohad; Garmire, Gordon P. et al.
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Partner: UNT College of Arts and Sciences
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X-Ray Spectral Constraints for z ≈ 2 Massive Galaxies: The Identification of Reflection-Dominated Active Galactic Nuclei

Description: This article uses the 4 Ms Chandra Deep Field-South survey to place direct constraints on the ubiquity of z ≈ 2 heavily obscured active galactic nuclei.
Date: June 6, 2011
Creator: Alexander, David M.; Bauer, Franz E.; Brandt, William Nielsen; Daddi, Emanuele; Hickox, Ryan; Lehmer, Bret et al.
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Partner: UNT College of Arts and Sciences
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The X-ray Spectral Properties and Variability of Luminous High-Redshift Active Galactic Nuclei

Description: This article contains a detailed investigation of moderate- to high-quality X-ray spectra of 10 of the most luminous active galactic nuclei known at z > 4.
Date: May 20, 2005
Creator: Shemmer, Ohad; Brandt, William Nielsen; Vignali, Christian; Schneider, Donald P.; Fan, Xiaohui; Richards, Gordon T. et al.
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Partner: UNT College of Arts and Sciences
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