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Multiwavelength monitoring of the narrow-line Seyfert 1 galaxy Arakelian 564. II. Ultraviolet continuum and emission-line variability

Description: This article presents the results of an intensive 2 month campaign of approximately daily spectrophotometric monitoring of the narrow-line Seyfert 1 galaxy Ark 564 with the Hubble Space Telescope.
Date: July 3, 2001
Creator: Collier, S.; Crenshaw, D.M.; Peterson, Bradley M.; Brandt, William Nielsen; Clavel, J.; Edelson, R. et al.
Partner: UNT College of Arts and Sciences

Reddening, Emission-Line, and Intrinsic Absorption Properties in the Narrow-Line Seyfert 1 Galaxy Arakelian 564

Description: This article uses Hubble Space Telescope UV and optical spectra of the narrow-line Seyfert 1 galaxy Ark 564 to investigate its internal reddening and properties of its emission-line and intrinsic UV absorption gas.
Date: October 12, 2001
Creator: Crenshaw, D.M.; Kraemer, S.B.; Turner, T.J.; Collier, S.; Peterson, Bradley M.; Brandt, William Nielsen et al.
Partner: UNT College of Arts and Sciences

Erratum: "Is there a metallicity-luminosity relationship in active galactic nuclei? The case of narrow-line Seyfert 1 galaxies"

Description: This erratum corrects a computational error affecting the calculation of the intrinsic luminosities of several objects in the article "Is there a metallicity-luminosity relationship in active galactic nuclei? The case of narrow-line Seyfert 1 galaxies." This does not affect any of the main results of the article.
Date: April 10, 2002
Creator: Shemmer, Ohad & Netzer, Hagai
Partner: UNT College of Arts and Sciences

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.
Partner: UNT College of Arts and Sciences

Optically Selected BL Lacertae Candidates from the Sloan Digital Sky Survey Data Release Seven

Description: This article presents a sample of 723 optically selected BL Lac candidates from the Sloan Digital Sky Survey Data Release 7 spectroscopic database.
Date: October 30, 2009
Creator: Plotkin, Richard M.; Anderson, Scott F.; Brandt, William Nielsen; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Hall, Patrick B. et al.
Partner: UNT College of Arts and Sciences

A Population of X-Ray Weak Quasars: PHL 1811 Analogs at High Redshift

Description: This article reports the results from Chandra and XMM-Newton observations of a sample of 10 type 1 quasars selected to have unusual UV emission-line properties similar to those of PHL 1811.
Date: April 15, 2011
Creator: Wu, Jianfeng; Brandt, William Nielsen; Hall, Patrick B.; Gibson, Robert R.; Richards, Gordon T.; Schneider, Donald P. et al.
Partner: UNT College of Arts and Sciences

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.
Partner: UNT College of Arts and Sciences

On The Performance of Quasar Reverberation Mapping in the Era of Time-Domain Photometric Surveys

Description: This article quantitatively assesses, by means of comprehensive numerical simulations, the ability of broadband photometric surveys to recover the broad emission line region size in quasars under various observing conditions and for a wide range of object properties.
Date: February 2, 2014
Creator: Chelouche, Doron; Shemmer, Ohad; Cotlier, Gabriel I.; Barth, Aaron J. & Rafter, Stephen E.
Partner: UNT College of Arts and Sciences

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.
Partner: UNT College of Arts and Sciences

PAH Emission and Star Formation in the Host of the z ~ 2.56 Cloverleaf QSO

Description: This article reports the first detection of the 6.2 and 7.7 μm infrared polycyclic aromatic hydrocarbon emission features in the spectrum of a high-redshift QSO, from the Spitzer IRS spectrum of the Cloverleaf lensed QSO.
Date: March 30, 2007
Creator: Lutz, Dieter; Sturm, Eckhard; Tacconi, Linda; Valiante, Elisabetta; Schweitzer, Mario; Netzer, Hagai et al.
Partner: UNT College of Arts and Sciences

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.
Partner: UNT College of Arts and Sciences

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.
Partner: UNT College of Arts and Sciences

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.
Partner: UNT College of Arts and Sciences

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.
Partner: UNT College of Arts and Sciences

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.
Partner: UNT College of Arts and Sciences

The 4Ms Chandra Deep Field-South Number Counts Apportioned By Source Class: Pervasive Active Galactic Nuclei and the Ascent of Normal Galaxies

Description: This article presents cumulative and differential number-count measurements for the recently completed 4 Ms Chandra Deep Field-South survey.
Date: April 9, 2012
Creator: Lehmer, Bret; Xue, Yongquan; Brandt, William Nielsen; Alexander, David M.; Bauer, Franz E.; Brusa, Marcella et al.
Partner: UNT College of Arts and Sciences