Search Menu
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information
Search Scholarly Publications

Title: The Spectroscopic Signature of Variability in High-redshift Quasars

Journal Article · · The Astrophysical Journal (Online)
 [1]; ORCiD logo [1];  [1];  [2]; ORCiD logo [3];  [4]; ORCiD logo [4];  [5]
  1. Univ. of Utah, Salt Lake City, UT (United States)
  2. Univ. of Utah, Salt Lake City, UT (United States); Pennsylvania State Univ., University Park, PA (United States)
  3. Apache Point Observatory and New Mexico State Univ., Sunspot, NM (United States); Moscow State Univ., Moscow (Russia). Sternberg Astronomical Inst.
  4. Apache Point Observatory and New Mexico State Univ., Sunspot, NM (United States)
  5. Pennsylvania State Univ., University Park, PA (United States). Inst. for Gravitation and the Cosmos
+ Show Author Affiliations

Using 16,421 spectra from a sample of 340 quasars (1.62 < z < 3.30) from the Sloan Digital Sky Survey (SDSS) Reverberation Mapping Project, we present an analysis of quasar spectral variability. We confirm the intrinsic Baldwin effect (BE) and brighter-means-bluer trends in which emission line strength and color are associated with changes in luminosity. We then create a composite differential spectrum that captures the wavelength dependence of quasar variability as a function of change in luminosity. When using a bandpass around 1740 Å to describe the luminosity, the differential spectrum follows a power law at longer wavelengths that breaks blueward of 1700 Å. However, the shape of the differential spectrum, the location of the power-law break, and the slope of the intrinsic BE all vary with the choice of bandpass used to define the change in quasar luminosity. We propose that the observed behavior can be explained by inhomogeneous accretion or slim accretion disk models where delays in the reprocessing of incident light on the accretion disk cause local deviations in temperature from the thin-disk model. Finally, we quantify the effects on cosmology studies that are due to the variations in the quasar spectrum in the Lyα forest wavelength range. Using the observed spectroscopic signatures to predict the quasar continuum over the interval 1040 < λ < 1200 Å, we find that the derived spectral templates can reduce the uncertainty of the Lyα forest continuum level in individual epochs from 17.2% to 7.7%, near the level where systematic errors in SDSS flux calibration are expected to dominate.

Research Organization:
Univ. of Utah, Salt Lake City, UT (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP); Alfred P. Sloan Foundation
Grant/Contract Number:
SC0009959
OSTI ID:
1611272
Journal Information:
The Astrophysical Journal (Online), Vol. 880, Issue 2; ISSN 1538-4357
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English

References (84)

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment journal April 2018
OzDES multifibre spectroscopy for the Dark Energy Survey: 3-yr results and first data release journal July 2017
The Baryon Oscillation Spectroscopic Survey of Sdss-Iii journal December 2012
The Sdss-Iv Extended Baryon Oscillation Spectroscopic Survey: Overview and Early data journal February 2016
Measurement of baryon acoustic oscillation correlations at z  = 2.3 with SDSS DR12 Ly α -Forests journal June 2017
Spectral Variability of Quasars in the Sloan Digital Sky Survey. I. Wavelength Dependence journal November 2005
Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe journal June 2017
Slim accretion disks journal September 1988
The correlation of line strength with luminosity and redshift from composite quasi-stellar object spectra journal November 2002
X-Ray Insights into the Nature of phl 1811 Analogs and weak Emission-Line Quasars: Unification with a Geometrically Thick Accretion Disk? journal May 2015
Spectral Variability of Quasars in the Sloan Digital Sky Survey. II. The C iv Line journal April 2006
Hubble Space Telescope STIS Ultraviolet Spectral Evidence of Outflow in Extreme Narrow‐Line Seyfert 1 Galaxies. II. Modeling and Interpretation journal August 2004
The Multi-Object, Fiber-Fed Spectrographs for the Sloan Digital sky Survey and the Baryon Oscillation Spectroscopic Survey journal July 2013
The Dark Energy Survey and operations: Year 1 conference August 2014
Spectral Classification and Redshift Measurement for the Sdss-Iii Baryon Oscillation Spectroscopic Survey journal October 2012
Baryon acoustic oscillations from the complete SDSS-III Ly α -quasar cross-correlation function at z = 2.4 journal December 2017
Quasar Accretion Disks are Strongly Inhomogeneous journal December 2010
Relative quasar luminosities determined from emission line strengths journal June 1978
The Dark Energy Survey
  • Sánchez, E.
  • THE DARK SIDE OF THE UNIVERSE: 2nd International Conference on The Dark Side of the Universe DSU 2006, AIP Conference Proceedings https://doi.org/10.1063/1.2409089
conference January 2006
The Extreme Ultraviolet Variability of Quasars journal October 2016
THE COMPOSITE SPECTRUM OF BOSS QUASARS SELECTED FOR STUDIES OF THE Ly α FOREST journal May 2016
X-RAY Periodicity in AGN journal November 2005
The Sloan Digital Sky Survey Reverberation Mapping Project: H α and H β Reverberation Measurements from First-year Spectroscopy and Photometry journal December 2017
The Dark Energy Survey journal June 2005
Line-driven winds and the UV turnover in AGN accretion discs journal January 2014
The one-dimensional Ly α forest power spectrum from BOSS journal November 2013
The Color Variability of Quasars journal December 2011
OzDES multifibre spectroscopy for the Dark Energy Survey: first-year operation and results journal July 2015
Characteristic QSO Accretion Disk Temperatures from Spectroscopic Continuum Variability journal May 2006
The Sloan Digital Sky Survey Quasar Catalog: twelfth data release text January 2016
Reverberation mapping of the emission line regions of Seyfert galaxies and quasars journal April 1982
Correcting for the Effects of Interstellar Extinction journal January 1999
Joint Bayesian Estimation of Quasar Continua and the Ly α Forest Flux Probability Distribution Function journal August 2017
Sdss-Iii: Massive Spectroscopic Surveys of the Distant Universe, the Milky way, and Extra-Solar Planetary Systems journal August 2011
Spectral Evolution in high Redshift Quasars from the Final Baryon Oscillation Spectroscopic Survey Sample journal December 2016
Quasar Evolution and the Baldwin Effect in the Large Bright Quasar Survey journal August 2001
REDSHIFT MEASUREMENT AND SPECTRAL CLASSIFICATION FOR eBOSS GALAXIES WITH THE REDMONSTER SOFTWARE journal December 2016
A Global Three-Dimensional Radiation Magneto-Hydrodynamic Simulation of Super-Eddington Accretion Disks journal November 2014
HST -COS OBSERVATIONS OF AGNs. II. EXTENDED SURVEY OF ULTRAVIOLET COMPOSITE SPECTRA FROM 159 ACTIVE GALACTIC NUCLEI journal September 2014
Baryon acoustic oscillations in the Ly α forest of BOSS DR11 quasars journal January 2015
Evidence for Large Temperature Fluctuations in Quasar Accretion Disks from Spectral Variability journal February 2014
Improved Spectrophotometric Calibration of the Sdss-Iii boss Quasar Sample journal November 2016
A study of the Baldwin effect in the IUE data set journal July 1990
Simulations of the OzDES AGN reverberation mapping project journal August 2015
Constraints on the temperature inhomogeneity in quasar accretion discs from the ultraviolet-optical spectral variability journal March 2015
Sloan Digital Sky Survey: Early Data Release journal January 2002
Predicting Quasar Continua near Ly α with Principal Component Analysis journal September 2018
Continuum and Emission‐Line Strength Relations for a Large Active Galactic Nuclei Sample journal December 2002
Updating quasar bolometric luminosity corrections: Updating quasar bolometric corrections journal February 2012
Reverberation mapping of active galactic nuclei journal March 1993
The Dark Energy Survey conference May 2012
The origin of the UV/optical lags in NGC 5548 journal April 2017
The Sloan Digital Sky Survey Quasar Catalog: Twelfth data release journal January 2017
THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: FIRST BROAD-LINE H β AND Mg II LAGS AT z ≳ 0.3 FROM SIX-MONTH SPECTROSCOPY journal February 2016
The origin and evolution of C iv Baldwin effect in QSOs from the Sloan Digital Sky Survey: C iv Baldwin effect in SDSS QSOs journal August 2008
The Baldwin effect in complete optically selected samples of quasars journal May 1992
The Lyman-α forest in three dimensions: measurements of large scale flux correlations from BOSS 1st-year data journal September 2011
ACCRETION DISK TEMPERATURES OF QSOs: CONSTRAINTS FROM THE EMISSION LINES journal May 2013
The 2.5 m Telescope of the Sloan Digital Sky Survey journal April 2006
The Sloan Digital sky Survey Reverberation Mapping Project: Technical Overview journal December 2014
Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe text January 2017
The Lyman-α forest in three dimensions: measurements of large scale flux correlations from BOSS 1st-year data text January 2011
The Color Variability of Quasars text January 2011
The Baryon Oscillation Spectroscopic Survey of SDSS-III text January 2012
Accretion Disk Temperatures of QSOs: Constraints from the Emission Lines text January 2012
The one-dimensional Ly-alpha forest power spectrum from BOSS text January 2013
Line driven winds and the UV turnover in AGN accretion discs text January 2013
Evidence for Large Temperature Fluctuations in Quasar Accretion Disks From Spectral Variability text January 2014
The Sloan Digital Sky Survey Reverberation Mapping Project: Technical Overview text January 2014
A Global Three Dimensional Radiation Magneto-hydrodynamic Simulation of Super-Eddington Accretion Disks text January 2014
Constraints on the temperature inhomogeneity in quasar accretion discs from the ultraviolet-optical spectral variability text January 2015
X-ray Insights into the Nature of PHL 1811 Analogs and Weak Emission-Line Quasars: Unification with a Geometrically Thick Accretion Disk? text January 2015
Improved Spectrophotometric Calibration of the SDSS-III BOSS Quasar Sample text January 2015
The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Overview and Early Data text January 2015
Redshift Measurement and Spectral Classification for eBOSS Galaxies with the Redmonster Software text January 2016
The Extreme Ultraviolet Variability of Quasars text January 2016
The Sloan Digital Sky Survey Quasar Catalog: twelfth data release text January 2016
Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe text January 2017
Joint Bayesian Estimation of Quasar Continua and the Lyman-Alpha Forest Flux Probability Distribution Function text January 2017
X-ray Periodicity in AGN text January 2004
Characteristic QSO Accretion Disk Temperatures from Spectroscopic Continuum Variability text January 2005
Spectral Variability of Quasars in the Sloan Digital Sky Survey. II: The C IV Line text January 2005
The 2.5 m Telescope of the Sloan Digital Sky Survey text January 2006
Correcting for the Effects of Interstellar Extinction text January 1998

Figures / Tables (10)

Table 1(p. 4)table Table 1
Figure 1(p. 5)figure Figure 1
Figure 2(p. 6)figure Figure 2
Figure 3(p. 6)figure Figure 3
Figure 4(p. 7)figure Figure 4
Figure 5(p. 7)figure Figure 5
Figure 6(p. 8)figure Figure 6
Table 2(p. 8)table Table 2
Figure 7(p. 10)figure Figure 7
Table 3(p. 11)table Table 3

Similar Records

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
Astronomy &amp; Astrophysics