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Title: CMB distortion from circumgalactic gas
Authors: Singh, Priyanka
Nath, Biman B.
Majumdar, S.
Silk, Joseph
Issue Date: 11-Apr-2015
Publisher: Oxford University Press for the Royal Astronomical Society
Citation: Monthly Notices of the Royal Astronomical Society, 2015, Vol. 448, p2384-2396
Abstract: We study the Sunyaev–Zel'dovich (SZ) distortion of the cosmic microwave background radiation from extensive circumgalactic gas (CGM) in massive galactic haloes. Recent observations have shown that galactic haloes contain a large amount of X-ray emitting gas at the virial temperature, as well as a significant amount of warm O vi absorbing gas. We consider the SZ distortion from the hot gas in those galactic haloes in which the gas cooling time is longer than the halo destruction time-scale. We show that the SZ distortion signal from the hot gas in these galactic haloes at redshifts z ≈ 1–8 can be significant at small angular scales (ℓ ∼ 104), and dominate over the signal from galaxy clusters. The estimated SZ signal for most massive galaxies (halo mass ≥1012.5 M⊙) is consistent with the marginal detection by Planck at these mass scales. We also consider the SZ effect from warm circumgalactic gas. The integrated Compton distortion from the warm O vi absorbing gas is estimated to be y ∼ 10−8, which could potentially be detected by experiments planned for the near future. Finally, we study the detectability of the SZ signal from circumgalactic gas in two types of surveys, a simple extension of the South Pole Telescope survey and a more futuristic cosmic-variance-limited survey. We find that these surveys can easily detect the kinetic Sunyaev–Zel'dovich signal from CGM. With the help of a Fisher matrix analysis, we find that it will be possible for these surveys to constrain the gas fraction in CGM, after marginalizing over cosmological parameters, to ≤33 per cent, in case of no redshift evolution of the gas fraction.
Description: Open Access
ISSN: 0035-8711
1365-2966 - (online)
Alternative Location:
Copyright: 2015 The authors & the Royal Astronomical Society
Appears in Collections:Research Papers (A&A)

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