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Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2022

H i constraints from the cross-correlation of eBOSS galaxies and Green Bank Telescope intensity maps

Laura Wolz
  • Function : Author
Alkistis Pourtsidou
  • Function : Author
Kiyoshi W. Masui
  • Function : Author
Tzu-Ching Chang
  • Function : Author
Eva-Maria Müller
  • Function : Author
Santiago Avila
  • Function : Author
David Bacon
  • Function : Author
Will J. Percival
  • Function : Author
Steven Cunnington
  • Function : Author
Chris Anderson
  • Function : Author
Xuelei Chen
Jean-Paul Kneib
Yi-Chao Li
  • Function : Author
Yu-Wei Liao
  • Function : Author
Ue-Li Pen
  • Function : Author
Jeffrey B. Peterson
  • Function : Author
Graziano Rossi
  • Function : Author
Donald P. Schneider
  • Function : Author
Jaswant Yadav
  • Function : Author
Gong-Bo Zhao
  • Function : Author

Abstract

We present the joint analysis of Neutral Hydrogen (H i) Intensity Mapping observations with three galaxy samples: the Luminous Red Galaxy (LRG) and Emission Line Galaxy (ELG) samples from the eBOSS survey, and the WiggleZ Dark Energy Survey sample. The H i intensity maps are Green Bank Telescope observations of the redshifted |$21\rm cm$| emission on |$100 \, {\rm deg}^2$| covering the redshift range 0.6 < z < 1.0. We process the data by separating and removing the foregrounds present in the radio frequencies with FastI ICA. We verify the quality of the foreground separation with mock realizations, and construct a transfer function to correct for the effects of foreground removal on the H i signal. We cross-correlate the cleaned H i data with the galaxy samples and study the overall amplitude as well as the scale dependence of the power spectrum. We also qualitatively compare our findings with the predictions by a semianalytical galaxy evolution simulation. The cross-correlations constrain the quantity |$\Omega _{\rm {H\,\small {I}}} b_{\rm {H\,\small {I}}} r_{\rm {H\,\small {I}},{\rm opt}}$| at an effective scale k_eff, where |$\Omega _\rm {H\,\small {I}}$| is the H  i density fraction, |$b_\rm {H\,\small {I}}$| is the H i bias, and |$r_{\rm {H\,\small {I}},{\rm opt}}$| the galaxy–hydrogen correlation coefficient, which is dependent on the H  i content of the optical galaxy sample. At |$k_{\rm eff}=0.31 \, h\,{\rm Mpc^{-1}}$| we find |$\Omega _{\rm {H\,\small {I}}} b_{\rm {H\,\small {I}}} r_{\rm {H\,\small {I}},{\rm Wig}} = [0.58 \pm 0.09 \, {\rm (stat) \pm 0.05 \, {\rm (sys)}}] \times 10^{-3}$| for GBT-WiggleZ, |$\Omega _{\rm {H\,\small {I}}} b_{\rm {H\,\small {I}}} r_{\rm {H\,\small {I}},{\rm ELG}} = [0.40 \pm 0.09 \, {\rm (stat) \pm 0.04 \, {\rm (sys)}}] \times 10^{-3}$| for GBT-ELG, and |$\Omega _{\rm {H\,\small {I}}} b_{\rm {H\,\small {I}}} r_{\rm {H\,\small {I}},{\rm LRG}} = [0.35 \pm 0.08 \, {\rm (stat) \pm 0.03 \, {\rm (sys)}}] \times 10^{-3}$| for GBT-LRG, at z ≃ 0.8. We also report results at |$k_{\rm eff}=0.24$| and |$k_{\rm eff}=0.48 \, h\,{\rm Mpc^{-1}}$|⁠. With little information on H i parameters beyond our local Universe, these are amongst the most precise constraints on neutral hydrogen density fluctuations in an underexplored redshift range.

Dates and versions

hal-03157126 , version 1 (02-03-2021)

Identifiers

Cite

Laura Wolz, Alkistis Pourtsidou, Kiyoshi W. Masui, Tzu-Ching Chang, Julian E. Bautista, et al.. H i constraints from the cross-correlation of eBOSS galaxies and Green Bank Telescope intensity maps. Monthly Notices of the Royal Astronomical Society, 2022, 510 (3), pp.3495-3511. ⟨10.1093/mnras/stab3621⟩. ⟨hal-03157126⟩
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