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  • ASTROPHYSICS  (2)
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  • 1
    Publication Date: 2019-07-13
    Description: We present results from two observations of the cosmic microwave background (CMB) performed from the South Pole during the 1993-1994 austral summer. Each observation employed a 3 deg peak-to-peak sinusoidal, single-difference chop and consisted of a 20 deg x 1 deg strip on the sky. The first observation used a receiver which operates in three channels between 38 and 45 GHz (Q-band) with a full width half maximum (FWHM) beam which varies from 1 deg to 1.15 deg. The second observation overlapped the first observation and used a receiver which operates in four channels between 26 and 36 GHz (Ka-band) with a FWHM beam which varies from 1.5 deg to 1.7 deg. Significant correlated structure is observed in all channels for each observation. The spectrum of the structure is consistent with a CMB spectrum and is formally inconsistent with diffuse synchrotron and free-free emission at the 5 sigma level. The amplitude of the structure is inconsistent with 20 K interstellar dust; however, the data do not discriminate against flat or inverted spectrum point sources. The root mean square amplitude (+/- 1 sigma) of the combined (Ka + Q) data is Delta T(sub rms) = 41.2(sup +15.5, sub -6.7) micro-K for an average window function which has a peak value of 0.97 at l = 68 and drops to e(exp -0.5) of the peak value at l = 36 and l = 106. A band power estimate of the CMB power spectrum, C(sub l), gives average value of (C(sub l)l(l + 1)/(2 pi))(sub B) = 1.77(sup +1.58, sub -0.54) x 10(exp -10).
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X); 443; 2; p. L57-L60
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  • 2
    Publication Date: 2019-07-12
    Description: A recent anisotropy experiment with a 30-arcmin beam is close to optimal for testing models in which cosmic structure arose from inflation-generated Gaussian density perturbations. Using a Bayesian analysis to constrain the amplitude of the perturbation spectrum, it is shown that adiabatic hot-dark-matter models are convincingly ruled out and cold-dark-matter models have anisotropies near the derived limits. Theories with broken scale invariance such as isocurvature baryon models are strongly constrained, as are models with extra power crafted to give significant large-scale structures and flows.
    Keywords: ASTROPHYSICS
    Type: Physical Review Letters (ISSN 0031-9007); 66; 2179-218
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