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
URI:	http://hdl.handle.net/2289/6234
ISSN:	0035-8711 1365-2966 - (online)
Alternative Location:	http://adsabs.harvard.edu/abs/2015MNRAS.448.2384S http://arxiv.org/abs/1408.4896 http://dx.doi.org/10.1093/mnras/stv155
Copyright:	2015 The authors & the Royal Astronomical Society
Appears in Collections:	Research Papers (A&A)

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