Fundamental physics from future weak-lensing calibrated Sunyaev-Zel’dovich galaxy cluster counts

• Published in: Physical review. D 2017-11, Vol.96 (10), Article 103525
• Main Authors: Madhavacheril, Mathew S., Battaglia, Nicholas, Miyatake, Hironao
• Format: Article
• Language: English
• Subjects: Big Bang theory; Calibration; Cosmic microwave background; Dark energy; Equations of state; Galactic clusters; Galaxies; Neutrinos; Optical measurement; Parameters; Red shift
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.96.103525

Future high-resolution measurements of the cosmic microwave background (CMB) will produce catalogs of tens of thousands of galaxy clusters through the thermal Sunyaev-Zel’dovich (tSZ) effect. We forecast how well different configurations of a CMB Stage-4 experiment can constrain cosmological parameters, in particular, the amplitude of structure as a function of redshift σ8(z), the sum of neutrino masses Σmν, and the dark energy equation of state w(z). A key element of this effort is calibrating the tSZ scaling relation by measuring the lensing signal around clusters. We examine how the mass calibration from future optical surveys like the Large Synoptic Survey Telescope (LSST) compares with a purely internal calibration using lensing of the CMB itself. We find that, due to its high-redshift leverage, internal calibration gives constraints on cosmological parameters comparable to the optical calibration, and can be used as a cross-check of systematics in the optical measurement. We also show that in contrast to the constraints using the CMB lensing power spectrum, lensing-calibrated tSZ cluster counts can detect a minimal Σmν at the 3–5σ level even when the dark energy equation of state is freed up.