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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.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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A new, faint population of X-ray transients

Description: This article reports on the detection of a remarkable new fast high-energy transient found in the Chandra Deep Field-South, robustly associated with a faint host in the CANDELS survey.
Date: February 15, 2017
Creator: Bauer, Franz E.; Treister, Ezequiel; Schawinski, K.; Schulze, S.; Luo, Bin; Alexander, David M. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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A Statistical Relation Between the X-ray Spectral Index and Eddington Ratio of Active Galactic Nuclei in Deep Surveys

Description: This article presents an investigation into how well the properties of the accretion flow on to a supermassive black hole may be coupled to those of the overlying hot corona.
Date: May 22, 2013
Creator: Brightman, M.; Silverman, John David; Mainieri, Vincenzo; Ueda, Yoshihiro; Schramm, Malte; Matsuoka, Kenta et al.
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Partner: UNT College of Arts and Sciences
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Ionised outflows in z ~ 2.4 quasar host galaxies

Description: This article presents a kinematical analysis of the [OIII]λ5007 emission line observed in six high-luminosity quasars at z ~ 2.4.
Date: August 1, 2015
Creator: Carniani, Stefano; Marconi, Alessandro; Maiolino, Roberto; Balmaverde, Barbara; Brusa, Marcella; Cano-Díaz, Mariana et al.
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Partner: UNT College of Arts and Sciences
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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.
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Partner: UNT College of Arts and Sciences
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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.
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Partner: UNT College of Arts and Sciences
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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.
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Partner: UNT College of Arts and Sciences
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Shedding New Light on Weak Emission-Line Quasars in the CIV-Hβ Parameter Space

Description: Article describes how weak emission-line quasars (WLQs) are a subset of Type 1 quasars that exhibit extremely weak Lyα+N V λ1240 and/or C IV λ1549 emission lines. The authors investigate the relationship between emission-line properties and accretion rate for a sample of 230 `ordinary' Type 1 quasars and 18 WLQs at z<0.5 and 1.5<z<3.5 that have rest-frame ultraviolet and optical spectral measurements.
Date: April 10, 2023
Creator: Ha, Trung; Dix, Cooper; Matthews, Brandon M.; Shemmer, Ohad; Brotherton, Michael S.; Myers, Adam D. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Science
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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.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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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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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.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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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.
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Partner: UNT College of Arts and Sciences
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Placing High-Redshift Quasars in Perspective: Unifying Distant Quasars with Their Lower Redshift Counterparts through Near-Infrared Spectroscopy

Description: I present spectroscopic measurements for 260 sources from the Gemini Near Infrared Spectrograph–Distant Quasar Survey (GNIRS-DQS). Being the largest uniform, homogeneous survey of its kind, it represents a flux-limited sample of Sloan Digital Sky Survey (SDSS) quasars at 1.5 < z < 3.5. A combination of the GNIRS and SDSS spectra covers principal quasar diagnostic features, chiefly the C IV λ1549, Mg II λλ2798, 2803, Hβ λ4861, and [O III] λλ4959, 5007 emission lines, in each source. The spectral… more
Date: May 2023
Creator: Matthews, Brandon M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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An Extreme X-Ray Variability Event of a Weak-line Quasar

Description: Article reports the discovery of an extreme X-ray flux rise (by a factor of ≳20) of the weak-line quasar Sloan Digital Sky Survey (SDSS) J153913.47+395423.4 (hereafter SDSS J1539+3954) at z = 1.935. SDSS J1539+3954 is the most-luminous object among radio-quiet type 1 active galactic nuclei (AGNs) where such dramatic X-ray variability has been observed.
Date: February 3, 2020
Creator: Ni, Q.; Brandt, W. N.; Yi, W.; Luo, B.; Timlin, J. D., III; Hall, P. B. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Science
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GRB 060505: A Possible Short-Duration Gamma-Ray Burst in a Star-Forming Region at a Redshift of 0.09

Description: This article reports the discovery of the GRB optical afterglow and observations of its environment using Gemini South, the Hubble Space Telescope, Chandra, Swift, and the Very Large Array.
Date: March 13, 2007
Creator: Ofek, Efran; Cenko, Brad; Gal-Yam, Avishay; Fox, Derek B.; Nakar, Ehud; Rau, Arne et al.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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The universal shape of the X-ray variability power spectrum of AGN up to z ∼ 3

Description: Authors of the article assert that they studied the ensemble X-ray variability properties of active galactic nuclei (AGN) over large ranges of timescale (20 ks ≤ T ≤ 14 yr), redshift (0 ≤ z ≲ 3), luminosity (1040 erg s−1 ≤ LX ≤ 1046 erg s−1), and black hole (BH) mass (106 ≤ M⊙ ≤ 109). The authors show that the data collected from archival observations and previous literature studies are fully consistent with a universal PSD form, which does not show any evidence for systematic evolution of shap… more
Date: May 8, 2023
Creator: Paolillo, Maurizio; Papadakis, I.; Brandt, William Nielsen; Bauer, Franz E.; Lanzuisi, G.; Allevato, V. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Science
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