COBE DMR data and the primordial index of density fluctuations
نویسندگان
چکیده
منابع مشابه
On Primordial Cosmological Density Fluctuations in the Einstein-cartan Gravity and Cobe Data
We study cosmological density fluctuations within a covariant and gaugeinvariant fluid-flow approach for a perfect fluid in the Einstein-Cartan gravity and derive the corresponding Raychaudhuri type of inhomogeneous coupled differential evolution equations of the second order. It appears that the quantum fluctuations of spin trigger primordial density inhomogeneities at the scale of weak intera...
متن کاملReappraising foreground contamination in the COBE-DMR data
With the advent of all-sky Hα surveys it is possible to determine a reliable free-free template of the diffuse interstellar medium (Dickinson, Davies & Davis 2003) which can be used in conjunction with the synchrotron and dust templates to correct CMB observations for diffuse Galactic foregrounds. We have used the COBE-DMR data at 31.5, 53 and 90 GHz and employed cross-correlation techniques to...
متن کاملComparison of Cobe Dmr and Rosat All-sky Survey Data
Statistical comparisons of microwave maps in the GHz range and X-ray maps at around 1 keV are an interesting probe to constrain different astrophysical phenomena. Possible correlations on various angular scales and with different frequency (energy) dependences, although not expected at present day experimental sensitivity, could in principle be due to Galactic emission/absorption, the Sunyaev-Z...
متن کاملThe Trispectrum of the 4 Year Cobe Dmr Data
We propose an estimator for the trispectrum of a scalar random field on a sphere, discuss its geometrical and statistical properties, and outline its implementation. By estimating the trispectrum of the 4 yr COBE Differential Microwave Radiometer experiment data (in HEALPix pixelization), we find new evidence of a non-Gaussian signal associated with a known systematic effect. We find that by re...
متن کاملA Brute Force Analysis of the Cobe Dmr Data
More than a dozen papers analyzing the COBE data have now appeared. We review the different techniques and compare them to a “brute force” likelihood analysis where we invert the full 4038× 4038 Galaxy-cut pixel covariance matrix. This method is optimal in the sense of producing minimal error bars, and is a useful reference point for comparing other analysis techniques. Our maximum-likelihood e...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1993
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/263.1.l17