Unbiased Cosmological Parameter Estimation from Emission-line Surveys with Interlopers

Henry S. Grasshorn Gebhardt, Donghui Jeong, Humna Awan, Joanna S. Bridge, Robin Ciardullo, Daniel Farrow, Karl Gebhardt, Gary J. Hill, Eiichiro Komatsu, Mallory Molina, Ana Paulino-Afonso, Shun Saito, Donald P. Schneider, Greg Zeimann

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The galaxy catalogs generated from low-resolution emission-line surveys often contain both foreground and background interlopers due to line misidentification, which can bias the cosmological parameter estimation. In this paper, we present a method for correcting the interloper bias by using the joint analysis of auto- and cross-power spectra of the main and the interloper samples. In particular, we can measure the interloper fractions from the cross-correlation between the interlopers and survey galaxies, because the true cross-correlation must be negligibly small. The estimated interloper fractions, in turn, remove the interloper bias in the cosmological parameter estimation. For example, in the Hobby-Eberly Telescope Dark Energy Experiment low-redshift (z < 0.5) [O ii] λ3727A emitters contaminate high-redshift (1.9 < z < 3.5) Lyα line emitters. We demonstrate that the joint-analysis method yields a high signal-to-noise ratio measurement of the interloper fractions while only marginally increasing the uncertainties in the cosmological parameters relative to the case without interlopers. We also show that the same is true for the high-latitude spectroscopic survey of the Wide-field Infrared Survey Telescope mission where contamination occurs between the Balmer-α line emitters at lower redshifts (1.1 < z < 1.9) and oxygen ([O iii] λ5007A) line emitters at higher redshifts (1.7 < z < 2.8).

Original languageEnglish (US)
Article number32
JournalAstrophysical Journal
Volume876
Issue number1
DOIs
StatePublished - May 1 2019

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emitters
cross correlation
telescopes
galaxies
dark energy
polar regions
signal-to-noise ratio
catalogs
power spectra
contamination
signal to noise ratios
oxygen
parameter estimation
energy
experiment
method
analysis

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Grasshorn Gebhardt, Henry S. ; Jeong, Donghui ; Awan, Humna ; Bridge, Joanna S. ; Ciardullo, Robin ; Farrow, Daniel ; Gebhardt, Karl ; Hill, Gary J. ; Komatsu, Eiichiro ; Molina, Mallory ; Paulino-Afonso, Ana ; Saito, Shun ; Schneider, Donald P. ; Zeimann, Greg. / Unbiased Cosmological Parameter Estimation from Emission-line Surveys with Interlopers. In: Astrophysical Journal. 2019 ; Vol. 876, No. 1.
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abstract = "The galaxy catalogs generated from low-resolution emission-line surveys often contain both foreground and background interlopers due to line misidentification, which can bias the cosmological parameter estimation. In this paper, we present a method for correcting the interloper bias by using the joint analysis of auto- and cross-power spectra of the main and the interloper samples. In particular, we can measure the interloper fractions from the cross-correlation between the interlopers and survey galaxies, because the true cross-correlation must be negligibly small. The estimated interloper fractions, in turn, remove the interloper bias in the cosmological parameter estimation. For example, in the Hobby-Eberly Telescope Dark Energy Experiment low-redshift (z < 0.5) [O ii] λ3727A emitters contaminate high-redshift (1.9 < z < 3.5) Lyα line emitters. We demonstrate that the joint-analysis method yields a high signal-to-noise ratio measurement of the interloper fractions while only marginally increasing the uncertainties in the cosmological parameters relative to the case without interlopers. We also show that the same is true for the high-latitude spectroscopic survey of the Wide-field Infrared Survey Telescope mission where contamination occurs between the Balmer-α line emitters at lower redshifts (1.1 < z < 1.9) and oxygen ([O iii] λ5007A) line emitters at higher redshifts (1.7 < z < 2.8).",
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Grasshorn Gebhardt, HS, Jeong, D, Awan, H, Bridge, JS, Ciardullo, R, Farrow, D, Gebhardt, K, Hill, GJ, Komatsu, E, Molina, M, Paulino-Afonso, A, Saito, S, Schneider, DP & Zeimann, G 2019, 'Unbiased Cosmological Parameter Estimation from Emission-line Surveys with Interlopers', Astrophysical Journal, vol. 876, no. 1, 32. https://doi.org/10.3847/1538-4357/ab12d5

Unbiased Cosmological Parameter Estimation from Emission-line Surveys with Interlopers. / Grasshorn Gebhardt, Henry S.; Jeong, Donghui; Awan, Humna; Bridge, Joanna S.; Ciardullo, Robin; Farrow, Daniel; Gebhardt, Karl; Hill, Gary J.; Komatsu, Eiichiro; Molina, Mallory; Paulino-Afonso, Ana; Saito, Shun; Schneider, Donald P.; Zeimann, Greg.

In: Astrophysical Journal, Vol. 876, No. 1, 32, 01.05.2019.

Research output: Contribution to journalArticle

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T1 - Unbiased Cosmological Parameter Estimation from Emission-line Surveys with Interlopers

AU - Grasshorn Gebhardt, Henry S.

AU - Jeong, Donghui

AU - Awan, Humna

AU - Bridge, Joanna S.

AU - Ciardullo, Robin

AU - Farrow, Daniel

AU - Gebhardt, Karl

AU - Hill, Gary J.

AU - Komatsu, Eiichiro

AU - Molina, Mallory

AU - Paulino-Afonso, Ana

AU - Saito, Shun

AU - Schneider, Donald P.

AU - Zeimann, Greg

PY - 2019/5/1

Y1 - 2019/5/1

N2 - The galaxy catalogs generated from low-resolution emission-line surveys often contain both foreground and background interlopers due to line misidentification, which can bias the cosmological parameter estimation. In this paper, we present a method for correcting the interloper bias by using the joint analysis of auto- and cross-power spectra of the main and the interloper samples. In particular, we can measure the interloper fractions from the cross-correlation between the interlopers and survey galaxies, because the true cross-correlation must be negligibly small. The estimated interloper fractions, in turn, remove the interloper bias in the cosmological parameter estimation. For example, in the Hobby-Eberly Telescope Dark Energy Experiment low-redshift (z < 0.5) [O ii] λ3727A emitters contaminate high-redshift (1.9 < z < 3.5) Lyα line emitters. We demonstrate that the joint-analysis method yields a high signal-to-noise ratio measurement of the interloper fractions while only marginally increasing the uncertainties in the cosmological parameters relative to the case without interlopers. We also show that the same is true for the high-latitude spectroscopic survey of the Wide-field Infrared Survey Telescope mission where contamination occurs between the Balmer-α line emitters at lower redshifts (1.1 < z < 1.9) and oxygen ([O iii] λ5007A) line emitters at higher redshifts (1.7 < z < 2.8).

AB - The galaxy catalogs generated from low-resolution emission-line surveys often contain both foreground and background interlopers due to line misidentification, which can bias the cosmological parameter estimation. In this paper, we present a method for correcting the interloper bias by using the joint analysis of auto- and cross-power spectra of the main and the interloper samples. In particular, we can measure the interloper fractions from the cross-correlation between the interlopers and survey galaxies, because the true cross-correlation must be negligibly small. The estimated interloper fractions, in turn, remove the interloper bias in the cosmological parameter estimation. For example, in the Hobby-Eberly Telescope Dark Energy Experiment low-redshift (z < 0.5) [O ii] λ3727A emitters contaminate high-redshift (1.9 < z < 3.5) Lyα line emitters. We demonstrate that the joint-analysis method yields a high signal-to-noise ratio measurement of the interloper fractions while only marginally increasing the uncertainties in the cosmological parameters relative to the case without interlopers. We also show that the same is true for the high-latitude spectroscopic survey of the Wide-field Infrared Survey Telescope mission where contamination occurs between the Balmer-α line emitters at lower redshifts (1.1 < z < 1.9) and oxygen ([O iii] λ5007A) line emitters at higher redshifts (1.7 < z < 2.8).

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