1995/04/18 by Lloyd Knox · 1 citation
Physics and Astronomy · #astro-ph
paper · pdf · doi:10.1103/physrevd.52.4307
published as Phys.Rev. D52 (1995) 4307-4318 · 28 pages of uuencoded postscript with 8 included figures. A postscript version is also available by anonymous ftp at ftp://astro.uchicago.edu/pub/astro/knox/fullsim.ps
arxiv created 1995/04/18 · arxiv updated 2009/12/01
Inflation produces nearly Harrison-Zel'dovich scalar and tensor perturbation spectra which lead to anisotropy in the cosmic microwave background (CMB). The amplitudes and shapes of these spectra can be parametrized by QS2, r≡ QT2/QS2, nS and nT where QS2 and QT2 are the scalar and tensor contributions to the square of the CMB quadrupole and nS and nT are the power-lawspectral indices. Even if we restrict ourselves to information from angles greater than one third of a degree, three of these observables can be measured with some precision. The combination 1301-nSQS2 can be known to better than ± 0.3%. The scalar index nS can be determined to better than ± 0.02. The ratio r can be known to about ± 0.1 for nS ≃ 1 and slightly better for smaller nS. The precision with which nT can be measured depends weakly on nS and strongly on r. For nS ≃ 1 nT can be determined with a precision of about ± 0.056(1.5+r)/r. A full-sky experiment with a 20'beam using technology available today, similar to those being planned by several groups, can achieve the above precision. Good angular resolution is more important than high signal-to-noise ratio; for a given detector sensitivity and observing time a smaller beam provides significantly more information than a larger beam. The uncertainties in nS and r are roughly proportional to the beam size. We briefly discuss the effects of uncertainty in the Hubble constant, baryon density, cosmological constant and ionization history.