The kinematic Sunyaev-Zel’dovich effect of the large-scale structure (II): the effect of modified gravity

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Roncarelli, M, Baldi, M, Villaescusa-Navarro, F
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: methods: numerical; cosmic background radiation; dark ages; reionization; first star; large-scale structure of Universe; cosmology: theory; South Pole; South pole
• Online Access: http://hdl.handle.net/11585/651682; https://doi.org/10.1093/mnras/sty2225; https://academic.oup.com/mnras/article/481/2/2497/5086087

The key to understand the nature of dark energy lies in our ability to probe the distant Universe. In this framework, the recent detection of the kinematic Sunyaev-Zel'dovich (kSZ) effect signature in the cosmic microwave background obtained with the South Pole Telescope (SPT) is extremely useful since this observable is sensitive to the high-redshift diffuse plasma. We analyse a set of cosmological hydrodynamical simulation with four different realizations of a Hu & Sawicki f(R) gravity model, parametrized by the values of (f) over bar (R,0)= (0, -10(-6) , -10(-5) , -10(-4 )), to compute the properties of the kSZ effect due to the ionized Universe and how they depend on (f) over bar (R,0) and on the redshift of reionization, z(re) . In the standard General Relativity limit ((f) over bar (R,0) = 0) we obtain an amplitude of the kSZ power spectrum of D-3000(kSZ)= 4.1 mu K (2) (z(re)= 8.8), close to the +1 sigma limit of the D-3000(kSZ )= (2.9 +/- 1.3) mu K-2 measurement by SPT. This corresponds to an upper limit on the kSZ contribute from patchy reionization of D-3000(kSZ,patchy) < 0.9 mu K-2 (95 per cent confidence level). Modified gravity boosts the kSZ signal by about 3, 12, and 50 per cent for (f) over bar (R,0)=(- 10(-6) , -10(-5) , -10(-4) ), respectively, with almost no dependence on the angular scale. This means that with modified gravity the limits on patchy reionization shrink significantly: for (f) over bar (R,0) =-10(-5) we obtain D-3000(kSZ,patchy) < 0.4 mu K (2) . Finally, we provide an analytical formula for the scaling of the kSZ power spectrum with z(re) and (f) over bar (R,0) at different multipoles: at l = 3000 we obtain D-3000(kSZ) proportional to z(re)(0.24) (1 + root vertical bar(f) over bar (R,0)vertical bar)(41).