2001/08/15 by J. M. LoSecco, John M. LoSecco, Grant J. Mathews +1
Physics and Astronomy · #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1103/physrevd.64.123002
published as Phys.Rev. D64 (2001) 123002 · 8 pages 2 Figures, PRD Submitted
arxiv created 2001/08/15 · openalex publication_date 2001/10/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Observers have demonstrated that it is now feasible to measure the cosmic microwave background (CMB) temperature at high redshifts. We explore the possible constraints on cosmology which might ultimately be derived from such measurements. In addition to providing a consistency check on standard and alternative cosmologies, possibilities include constraints on the inhomogeneity and anisotropy of the universe at intermediate redshift z\ensuremath\lesssim10, an independent probe of peculiar motions with respect to the Hubble flow, constraining the epoch of reionization, and the time variability of the fine structure constant. We argue that the best possibility is as a probe of peculiar motions. We show, however, that the current measurement uncertainty (\ensuremathΔT=\ifmmode±\else\textpm\fi0.002K) in the local present absolute CMB temperature imposes intrinsic limits on the use of such CMB temperature measurements as a cosmological probe. At best, anisotropies at intermediate redshift could only be constrained at a level of \ensuremath\gtrsim0.1% and peculiar motions could only be determined to an uncertainty of \ensuremath\gtrsim311kms^\ensuremath-1. If the high z CMB temperature can only be measured with a precision comparable to the uncertainty of the local interstellar CMB temperature, then peculiar motions could be determined to an uncertainty of 1101(1+z)^\ensuremath-1[\ensuremathΔTCMB(z)/0.01K]kms^\ensuremath-1.