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Abstract: We present an alternative estimate of the unresolved point sourcecontribution to the WMAP temperature power spectrum based on current knowledgeof sources from radio surveys in the 1.4-90 GHz range. We implement astochastic extrapolation of radio point sources in the NRAO-VLA Sky SurveyNVSS catalog, from the original 1.4 GHz to the ~ 100 GHz frequency rangerelevant for CMB experiments. With a bootstrap approach, we generate anensemble of realizations that provides the probability distribution for theflux of each NVSS source at the final frequency. The predicted source countsagree with WMAP results for S > 1 Jy and the corresponding sky maps correlatewith WMAP observed maps in Q-, V- and W- bands, for sources with flux S > 0.2Jy. The low-frequency radio surveys found a steeper frequency dependence forsources just below the WMAP nominal threshold than the one estimated by theWMAP team. This feature is present in our simulations and translates into ashift of 0.3-0.4 \sigma in the estimated value of the tilt of the powerspectrum of scalar perturbation, n s, as well as \omega c. This approachdemonstrates the use of external point sources datasets for CMB data analysis.



Autor: Loris P.L. Colombo, Elena Pierpaoli

Fuente: https://arxiv.org/



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