We present a forecast of the pairwise kinematic Sunyaev-Zel’dovich (kSZ) measurement that will be achievable with the future CMB-S4 experiment. CMB-S4 is the next stage for ground-based cosmic microwave background experiments, with a planned wide-area survey that will observe approximately 50% of the sky. We construct a simulated sample of galaxy clusters that have been optically selected in a Legacy Survey of Space and Time–like survey and have spectroscopic redshifts. For this cluster sample, assuming the likelihood is Gaussian, we predict that CMB-S4 will reject the null hypothesis of zero pairwise kSZ signal at 36𝜎. We estimate the effects of systematic uncertainties such as scatter in the mass-richness scaling relation and cluster miscentering. We find that these effects can reduce the signal-to-noise ratio of the CMB-S4 pairwise kSZ measurement by 20%. We explore the constraining power of the measured kSZ signal in combination with measurements of the galaxy clusters’ thermal SZ emission on two extensions to the standard cosmological model. The first extension allows the dark energy equation of state 𝑤 to vary. We find the CMB-S4 pairwise kSZ measurement yields a modest reduction in the uncertainty on 𝑤 by a factor of 1.36 over the Planck’s 2018 uncertainty. The second extension tests general relativity by varying the growth index 𝛾. In conclusion, we find that CMB-S4’s pairwise kSZ measurement will yield a 28𝜎 constraint on 𝛾 and strongly constrain alternative theories of gravity.
Schiappucci, E., et al. "Constraining cosmological parameters using the pairwise kinematic Sunyaev-Zel’dovich effect with CMB-S4 and future galaxy cluster surveys." Physical Review. D., vol. 111, no. 6, Mar. 2025. https://doi.org/10.1103/physrevd.111.063541
Schiappucci, E., Raghunathan, S., To, C., Bianchini, F., Reichardt, C. L., Battaglia, N., Hadzhiyska, B., Kim, S., Melin, J. B., Sifón, C., & Vavagiakis, E. M. (2025). Constraining cosmological parameters using the pairwise kinematic Sunyaev-Zel’dovich effect with CMB-S4 and future galaxy cluster surveys. Physical Review. D., 111(6). https://doi.org/10.1103/physrevd.111.063541
Schiappucci, E., Raghunathan, S., To, C., et al., "Constraining cosmological parameters using the pairwise kinematic Sunyaev-Zel’dovich effect with CMB-S4 and future galaxy cluster surveys," Physical Review. D. 111, no. 6 (2025), https://doi.org/10.1103/physrevd.111.063541
@article{osti_2575474,
author = {Schiappucci, E. and Raghunathan, S. and To, C. and Bianchini, F. and Reichardt, C. L. and Battaglia, N. and Hadzhiyska, B. and Kim, S. and Melin, J. B. and Sifón, C. and others},
title = {Constraining cosmological parameters using the pairwise kinematic Sunyaev-Zel’dovich effect with CMB-S4 and future galaxy cluster surveys},
annote = {We present a forecast of the pairwise kinematic Sunyaev-Zel’dovich (kSZ) measurement that will be achievable with the future CMB-S4 experiment. CMB-S4 is the next stage for ground-based cosmic microwave background experiments, with a planned wide-area survey that will observe approximately 50% of the sky. We construct a simulated sample of galaxy clusters that have been optically selected in a Legacy Survey of Space and Time–like survey and have spectroscopic redshifts. For this cluster sample, assuming the likelihood is Gaussian, we predict that CMB-S4 will reject the null hypothesis of zero pairwise kSZ signal at 36𝜎. We estimate the effects of systematic uncertainties such as scatter in the mass-richness scaling relation and cluster miscentering. We find that these effects can reduce the signal-to-noise ratio of the CMB-S4 pairwise kSZ measurement by 20%. We explore the constraining power of the measured kSZ signal in combination with measurements of the galaxy clusters’ thermal SZ emission on two extensions to the standard cosmological model. The first extension allows the dark energy equation of state 𝑤 to vary. We find the CMB-S4 pairwise kSZ measurement yields a modest reduction in the uncertainty on 𝑤 by a factor of 1.36 over the Planck’s 2018 uncertainty. The second extension tests general relativity by varying the growth index 𝛾. In conclusion, we find that CMB-S4’s pairwise kSZ measurement will yield a 28𝜎 constraint on 𝛾 and strongly constrain alternative theories of gravity.},
doi = {10.1103/physrevd.111.063541},
url = {https://www.osti.gov/biblio/2575474},
journal = {Physical Review. D.},
issn = {ISSN 2470-0029},
number = {6},
volume = {111},
place = {United States},
publisher = {American Physical Society (APS)},
year = {2025},
month = {03}}
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); National Energy Research Scientific Computing Center (NERSC); National Science Foundation (NSF)
Grant/Contract Number:
AC02-05CH11231; AC02-76SF00515
OSTI ID:
2575474
Alternate ID(s):
OSTI ID: 2563499 OSTI ID: 2570289
Journal Information:
Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 6 Vol. 111; ISSN 2470-0010; ISSN 2470-0029