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

Understand

We present the joint analysis of Neutral Hydrogen (HI) 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 HI intensity maps are Green Bank Telescope observations of the redshifted 21cm emission on 100deg2 covering the redshift range $0.6<z<1.0$.
• We process the data by separating and removing the foregrounds with FastICA, and construct a transfer function to correct for the effects of foreground removal on the HI signal.
• We cross-correlate the cleaned HI data with the galaxy samples and study the overall amplitude as well as the scale-dependence of the power spectrum.