THE COMPOSITE SPECTRUM of BOSS QUASARS SELECTED for STUDIES of the Lyα FOREST

Harris W. David, David W. Harris, Trey W. Jensen, Nao Suzuki, Julian E. Bautista, Kyle S. Dawson, M. Vivek, Joel R. Brownstein, Jian Ge, Fred Hamann, H. Herbst, Linhua Jiang, Sarah E. Moran, Adam D. Myers, Matthew D. Olmstead, Donald P. Schneider

Research output: Contribution to journalArticle

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Abstract

The Baryon Oscillation Spectroscopic Survey (BOSS) has collected more than 150,000 2.1 ≤ z ≤ 3.5 quasar spectra since 2009. Using this unprecedented sample, we create a composite spectrum in the rest-frame of 102,150 quasar spectra from 800-3300 at a signal-to-noise ratio close to 1000 per pixel (Δv of 69 km s-1). Included in this analysis is a correction to account for flux calibration residuals in the BOSS spectrophotometry. We determine the spectral index as a function of redshift of the full sample, warp the composite spectrum to match the median spectral index, and compare the resulting spectrum to Sloan Digital Sky Survey (SDSS) photometry used in target selection. The quasar composite matches the color of the quasar population to 0.02 mag in g - r, 0.03 mag in r - i, and 0.01 mag in i - z over the redshift range 2.2 < z < 2.6. The composite spectrum deviates from the imaging photometry by 0.05 mag around z = 2.7, likely due to differences in target selection as the quasar colors become similar to the stellar locus at this redshift. Finally, we characterize the line features in the high signal-to-noise composite and identify nine faint lines not found in the previous composite spectrum from SDSS.

Original languageEnglish (US)
Article number155
JournalAstronomical Journal
Volume151
Issue number6
DOIs
StatePublished - Jun 2016

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baryons
oscillation
quasars
oscillations
composite materials
photometry
color
spectrophotometry
loci
signal-to-noise ratio
pixel
signal to noise ratios
pixels
calibration

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

David, H. W., Harris, D. W., Jensen, T. W., Suzuki, N., Bautista, J. E., Dawson, K. S., ... Schneider, D. P. (2016). THE COMPOSITE SPECTRUM of BOSS QUASARS SELECTED for STUDIES of the Lyα FOREST. Astronomical Journal, 151(6), [155]. https://doi.org/10.3847/0004-6256/151/6/155
David, Harris W. ; Harris, David W. ; Jensen, Trey W. ; Suzuki, Nao ; Bautista, Julian E. ; Dawson, Kyle S. ; Vivek, M. ; Brownstein, Joel R. ; Ge, Jian ; Hamann, Fred ; Herbst, H. ; Jiang, Linhua ; Moran, Sarah E. ; Myers, Adam D. ; Olmstead, Matthew D. ; Schneider, Donald P. / THE COMPOSITE SPECTRUM of BOSS QUASARS SELECTED for STUDIES of the Lyα FOREST. In: Astronomical Journal. 2016 ; Vol. 151, No. 6.
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abstract = "The Baryon Oscillation Spectroscopic Survey (BOSS) has collected more than 150,000 2.1 ≤ z ≤ 3.5 quasar spectra since 2009. Using this unprecedented sample, we create a composite spectrum in the rest-frame of 102,150 quasar spectra from 800-3300 at a signal-to-noise ratio close to 1000 per pixel (Δv of 69 km s-1). Included in this analysis is a correction to account for flux calibration residuals in the BOSS spectrophotometry. We determine the spectral index as a function of redshift of the full sample, warp the composite spectrum to match the median spectral index, and compare the resulting spectrum to Sloan Digital Sky Survey (SDSS) photometry used in target selection. The quasar composite matches the color of the quasar population to 0.02 mag in g - r, 0.03 mag in r - i, and 0.01 mag in i - z over the redshift range 2.2 < z < 2.6. The composite spectrum deviates from the imaging photometry by 0.05 mag around z = 2.7, likely due to differences in target selection as the quasar colors become similar to the stellar locus at this redshift. Finally, we characterize the line features in the high signal-to-noise composite and identify nine faint lines not found in the previous composite spectrum from SDSS.",
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David, HW, Harris, DW, Jensen, TW, Suzuki, N, Bautista, JE, Dawson, KS, Vivek, M, Brownstein, JR, Ge, J, Hamann, F, Herbst, H, Jiang, L, Moran, SE, Myers, AD, Olmstead, MD & Schneider, DP 2016, 'THE COMPOSITE SPECTRUM of BOSS QUASARS SELECTED for STUDIES of the Lyα FOREST', Astronomical Journal, vol. 151, no. 6, 155. https://doi.org/10.3847/0004-6256/151/6/155

THE COMPOSITE SPECTRUM of BOSS QUASARS SELECTED for STUDIES of the Lyα FOREST. / David, Harris W.; Harris, David W.; Jensen, Trey W.; Suzuki, Nao; Bautista, Julian E.; Dawson, Kyle S.; Vivek, M.; Brownstein, Joel R.; Ge, Jian; Hamann, Fred; Herbst, H.; Jiang, Linhua; Moran, Sarah E.; Myers, Adam D.; Olmstead, Matthew D.; Schneider, Donald P.

In: Astronomical Journal, Vol. 151, No. 6, 155, 06.2016.

Research output: Contribution to journalArticle

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AU - David, Harris W.

AU - Harris, David W.

AU - Jensen, Trey W.

AU - Suzuki, Nao

AU - Bautista, Julian E.

AU - Dawson, Kyle S.

AU - Vivek, M.

AU - Brownstein, Joel R.

AU - Ge, Jian

AU - Hamann, Fred

AU - Herbst, H.

AU - Jiang, Linhua

AU - Moran, Sarah E.

AU - Myers, Adam D.

AU - Olmstead, Matthew D.

AU - Schneider, Donald P.

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AB - The Baryon Oscillation Spectroscopic Survey (BOSS) has collected more than 150,000 2.1 ≤ z ≤ 3.5 quasar spectra since 2009. Using this unprecedented sample, we create a composite spectrum in the rest-frame of 102,150 quasar spectra from 800-3300 at a signal-to-noise ratio close to 1000 per pixel (Δv of 69 km s-1). Included in this analysis is a correction to account for flux calibration residuals in the BOSS spectrophotometry. We determine the spectral index as a function of redshift of the full sample, warp the composite spectrum to match the median spectral index, and compare the resulting spectrum to Sloan Digital Sky Survey (SDSS) photometry used in target selection. The quasar composite matches the color of the quasar population to 0.02 mag in g - r, 0.03 mag in r - i, and 0.01 mag in i - z over the redshift range 2.2 < z < 2.6. The composite spectrum deviates from the imaging photometry by 0.05 mag around z = 2.7, likely due to differences in target selection as the quasar colors become similar to the stellar locus at this redshift. Finally, we characterize the line features in the high signal-to-noise composite and identify nine faint lines not found in the previous composite spectrum from SDSS.

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David HW, Harris DW, Jensen TW, Suzuki N, Bautista JE, Dawson KS et al. THE COMPOSITE SPECTRUM of BOSS QUASARS SELECTED for STUDIES of the Lyα FOREST. Astronomical Journal. 2016 Jun;151(6). 155. https://doi.org/10.3847/0004-6256/151/6/155