Forecasting the cross-correlation of the CSST galaxy survey with the FAST H i Intensity Map
ABSTRACT The cross-correlation of optical galaxies with the neutral hydrogen (H i) radiation intensity can enhance the signal-to-noise ratio (SNR) of the H i intensity measurement. In this paper, we investigate the cross-correlation of the galaxy samples obtained by the spectroscopic survey of the C...
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Published in | Monthly notices of the Royal Astronomical Society Vol. 515; no. 4; pp. 5894 - 5904 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford University Press
19.08.2022
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Subjects | |
Online Access | Get full text |
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Summary: | ABSTRACT
The cross-correlation of optical galaxies with the neutral hydrogen (H i) radiation intensity can enhance the signal-to-noise ratio (SNR) of the H i intensity measurement. In this paper, we investigate the cross-correlation of the galaxy samples obtained by the spectroscopic survey of the China Space Station Telescope (CSST) with the H i Intensity mapping (IM) survey of the Five-hundred-meter Aperture Spherical Telescope (FAST). Using the IllusitrisTNG simulation result at redshift 0.2 ∼ 0.3, we generate mock data of the CSST survey and a FAST L-band drift scan survey. The CSST spectroscopic survey can yield a sample of galaxies with a high comoving number density of $10^{-2}\, ({\ \rm Mpc}\,h^{ -1})^{-3}$ at z ∼ 0.3. We cross-correlate the foreground-removed radio intensity with the CSST galaxies, including both the whole sample, and red and blue galaxy subsamples separately. We find that in all cases the H i and optical galaxies are well correlated. The total H i abundance can be measured with a high precision from this correlation. A relative error of $\sim 0.6{{\ \rm per\ cent}}$ for $\Omega _{\rm H\, \small {I}}$ could be achieved at z ∼ 0.3 for an overlapping survey area of $10\,000\, {\ \rm deg}^2$. |
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ISSN: | 0035-8711 1365-2966 |
DOI: | 10.1093/mnras/stac2185 |