SPECTRAL EVOLUTION in HIGH REDSHIFT QUASARS from the FINAL BARYON OSCILLATION SPECTROSCOPIC SURVEY SAMPLE

Trey W. Jensen, M. Vivek, Kyle S. Dawson, Scott F. Anderson, Julian Bautista, Dmitry Bizyaev, William N. Brandt, Joel R. Brownstein, Paul Green, David W. Harris, Vikrant Kamble, Ian D. McGreer, Andrea Merloni, Adam Myers, Daniel Oravetz, Kaike Pan, Isabelle Pâris, Donald P. Schneider, Audrey Simmons, Nao Suzuki

Research output: Contribution to journalArticle

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Abstract

We report on the diversity in quasar spectra from the Baryon Oscillation Spectroscopic Survey. After filtering the spectra to mitigate selection effects and Malmquist bias associated with a nearly flux-limited sample, we create high signal-to-noise ratio composite spectra from 58,656 quasars (2.1 ≤ z ≤ 3.5), binned by luminosity, spectral index, and redshift. With these composite spectra, we confirm the traditional Baldwin effect (BE, i.e., the anticorrelation of C IV equivalent width (EW) and luminosity) that follows the relation Wλ ∝ Lβw with slope βw = -0.35 ± 0.004, -0.35 ± 0.005, and -0.41 ± 0.005 for z = 2.25, 2.46, and 2.84, respectively. In addition to the redshift evolution in the slope of the BE, we find redshift evolution in average quasar spectral features at fixed luminosity. The spectroscopic signature of the redshift evolution is correlated at 98% with the signature of varying luminosity, indicating that they arise from the same physical mechanism. At a fixed luminosity, the average C IV FWHM decreases with increasing redshift and is anti-correlated with C IV EW. The spectroscopic signature associated with C IV FWHM suggests that the trends in luminosity and redshift are likely caused by a superposition of effects that are related to black hole mass and Eddington ratio. The redshift evolution is the consequence of a changing balance between these two quantities as quasars evolve toward a population with lower typical accretion rates at a given black hole mass.

Original languageEnglish (US)
Article number199
JournalAstrophysical Journal
Volume833
Issue number2
DOIs
StatePublished - Dec 20 2016

Fingerprint

baryons
oscillation
luminosity
quasars
oscillations
signatures
slopes
composite materials
mass ratios
signal-to-noise ratio
signal to noise ratios
accretion
trends
effect

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Jensen, T. W., Vivek, M., Dawson, K. S., Anderson, S. F., Bautista, J., Bizyaev, D., ... Suzuki, N. (2016). SPECTRAL EVOLUTION in HIGH REDSHIFT QUASARS from the FINAL BARYON OSCILLATION SPECTROSCOPIC SURVEY SAMPLE. Astrophysical Journal, 833(2), [199]. https://doi.org/10.3847/1538-4357/833/2/199
Jensen, Trey W. ; Vivek, M. ; Dawson, Kyle S. ; Anderson, Scott F. ; Bautista, Julian ; Bizyaev, Dmitry ; Brandt, William N. ; Brownstein, Joel R. ; Green, Paul ; Harris, David W. ; Kamble, Vikrant ; McGreer, Ian D. ; Merloni, Andrea ; Myers, Adam ; Oravetz, Daniel ; Pan, Kaike ; Pâris, Isabelle ; Schneider, Donald P. ; Simmons, Audrey ; Suzuki, Nao. / SPECTRAL EVOLUTION in HIGH REDSHIFT QUASARS from the FINAL BARYON OSCILLATION SPECTROSCOPIC SURVEY SAMPLE. In: Astrophysical Journal. 2016 ; Vol. 833, No. 2.
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abstract = "We report on the diversity in quasar spectra from the Baryon Oscillation Spectroscopic Survey. After filtering the spectra to mitigate selection effects and Malmquist bias associated with a nearly flux-limited sample, we create high signal-to-noise ratio composite spectra from 58,656 quasars (2.1 ≤ z ≤ 3.5), binned by luminosity, spectral index, and redshift. With these composite spectra, we confirm the traditional Baldwin effect (BE, i.e., the anticorrelation of C IV equivalent width (EW) and luminosity) that follows the relation Wλ ∝ Lβw with slope βw = -0.35 ± 0.004, -0.35 ± 0.005, and -0.41 ± 0.005 for z = 2.25, 2.46, and 2.84, respectively. In addition to the redshift evolution in the slope of the BE, we find redshift evolution in average quasar spectral features at fixed luminosity. The spectroscopic signature of the redshift evolution is correlated at 98{\%} with the signature of varying luminosity, indicating that they arise from the same physical mechanism. At a fixed luminosity, the average C IV FWHM decreases with increasing redshift and is anti-correlated with C IV EW. The spectroscopic signature associated with C IV FWHM suggests that the trends in luminosity and redshift are likely caused by a superposition of effects that are related to black hole mass and Eddington ratio. The redshift evolution is the consequence of a changing balance between these two quantities as quasars evolve toward a population with lower typical accretion rates at a given black hole mass.",
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Jensen, TW, Vivek, M, Dawson, KS, Anderson, SF, Bautista, J, Bizyaev, D, Brandt, WN, Brownstein, JR, Green, P, Harris, DW, Kamble, V, McGreer, ID, Merloni, A, Myers, A, Oravetz, D, Pan, K, Pâris, I, Schneider, DP, Simmons, A & Suzuki, N 2016, 'SPECTRAL EVOLUTION in HIGH REDSHIFT QUASARS from the FINAL BARYON OSCILLATION SPECTROSCOPIC SURVEY SAMPLE', Astrophysical Journal, vol. 833, no. 2, 199. https://doi.org/10.3847/1538-4357/833/2/199

SPECTRAL EVOLUTION in HIGH REDSHIFT QUASARS from the FINAL BARYON OSCILLATION SPECTROSCOPIC SURVEY SAMPLE. / Jensen, Trey W.; Vivek, M.; Dawson, Kyle S.; Anderson, Scott F.; Bautista, Julian; Bizyaev, Dmitry; Brandt, William N.; Brownstein, Joel R.; Green, Paul; Harris, David W.; Kamble, Vikrant; McGreer, Ian D.; Merloni, Andrea; Myers, Adam; Oravetz, Daniel; Pan, Kaike; Pâris, Isabelle; Schneider, Donald P.; Simmons, Audrey; Suzuki, Nao.

In: Astrophysical Journal, Vol. 833, No. 2, 199, 20.12.2016.

Research output: Contribution to journalArticle

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AU - Jensen, Trey W.

AU - Vivek, M.

AU - Dawson, Kyle S.

AU - Anderson, Scott F.

AU - Bautista, Julian

AU - Bizyaev, Dmitry

AU - Brandt, William N.

AU - Brownstein, Joel R.

AU - Green, Paul

AU - Harris, David W.

AU - Kamble, Vikrant

AU - McGreer, Ian D.

AU - Merloni, Andrea

AU - Myers, Adam

AU - Oravetz, Daniel

AU - Pan, Kaike

AU - Pâris, Isabelle

AU - Schneider, Donald P.

AU - Simmons, Audrey

AU - Suzuki, Nao

PY - 2016/12/20

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N2 - We report on the diversity in quasar spectra from the Baryon Oscillation Spectroscopic Survey. After filtering the spectra to mitigate selection effects and Malmquist bias associated with a nearly flux-limited sample, we create high signal-to-noise ratio composite spectra from 58,656 quasars (2.1 ≤ z ≤ 3.5), binned by luminosity, spectral index, and redshift. With these composite spectra, we confirm the traditional Baldwin effect (BE, i.e., the anticorrelation of C IV equivalent width (EW) and luminosity) that follows the relation Wλ ∝ Lβw with slope βw = -0.35 ± 0.004, -0.35 ± 0.005, and -0.41 ± 0.005 for z = 2.25, 2.46, and 2.84, respectively. In addition to the redshift evolution in the slope of the BE, we find redshift evolution in average quasar spectral features at fixed luminosity. The spectroscopic signature of the redshift evolution is correlated at 98% with the signature of varying luminosity, indicating that they arise from the same physical mechanism. At a fixed luminosity, the average C IV FWHM decreases with increasing redshift and is anti-correlated with C IV EW. The spectroscopic signature associated with C IV FWHM suggests that the trends in luminosity and redshift are likely caused by a superposition of effects that are related to black hole mass and Eddington ratio. The redshift evolution is the consequence of a changing balance between these two quantities as quasars evolve toward a population with lower typical accretion rates at a given black hole mass.

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