First Intrinsic Anisotropy Observations with the Cosmic Background Imager
/ Authors
S. Padin, J. Cartwright, B. Mason, T. Pearson, A. Readhead, M. Shepherd, J. Sievers, P. Udomprasert, W. Holzapfel, Steven T. Myers
and 5 more authors
/ Abstract
We present the first results of observations of the intrinsic anisotropy of the cosmic microwave background radiation with the Cosmic Background Imager from a site at 5080 m altitude in northern Chile. Our observations show a sharp decrease in Cl in the range l = 400-1500. The broadband amplitudes we have measured are δTband = 58.7 μK for l = 603 and δTband = 29.7 μK for l = 1190, where these are half-power widths in l. Such a decrease in power at high l is one of the fundamental predictions of the standard cosmological model, and these are the first observations which cover a broad enough l range to show this decrease in a single experiment. The Cl we have measured enables us to place limits on the density parameter, Ωtot ≤ 0.4 or Ωtot ≥ 0.7 (90% confidence).
Journal: The Astrophysical Journal Letters
DOI: 10.1086/319142