Journal article
Determining the HI content of galaxies via intensity mapping cross-correlations
L Wolz, C Blake, JSB Wyithe
Monthly Notices of the Royal Astronomical Society | OXFORD UNIV PRESS | Published : 2017
Abstract
We propose an innovative method for measuring the neutral hydrogen (H I) content of an optically selected spectroscopic sample of galaxies through cross-correlation with HI intensity mapping measurements. We show that the HI-galaxy cross-power spectrum contains an additive shot noise term that scales with the average HI brightness temperature of the optically selected galaxies, allowing constraints to be placed on the average HI mass per galaxy. This approach can estimate the HI content of populations too faint to directly observe through their 21-cm emission over a wide range of redshifts. This cross-correlation, as a function of optical luminosity or colour, can be used to derive HI-scalin..
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Awarded by National Science Foundation
Funding Acknowledgements
We thank Paul Geil and Martin Meyer for useful discussions throughout this project. We thank the anonymous referee for their useful suggestions to improve the final form of the article. LW is supported by an Australian Research Council (ARC) Discovery Early Career Researcher Award (DE170100356). Some of this work was performed at the Aspen Center for Physics, which is supported by National Science Foundation grant PHY-1066293. This research was conducted by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO) through project number CE110001020.