Effect of Foregrounds on the CMBR Multipole Alignment - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We analyze the effect of foregrounds on the observed alignment of CMBRquadrupole and octopole. The alignment between these multipoles is studied byusing a symmetry based approach which assigns a principal eigenvector PEV oran axis with each multipole. We determine the significance of alignment betweenthese multipoles by using the Internal Linear Combination ILC 5 and 7 yearmap s and also the maps obtained by using the Internal Power SpectrumEstimation IPSE procedure. The effect of foreground cleaning is studied indetail within the framework of the IPSE method both analytically andnumerically. By using simulated CMBR data, we study how the PEVs of the puresimulated CMB map differ from those of the final cleaned map. We find that, ingeneral, the shift in the PEVs is relatively small and in random directions.Due to the random nature of the shift we conclude that it can only lead tomisalignment rather than alignment of multipoles. We also directly estimate thesignificance of alignment by using simulated cleaned maps. We find that theresults in this case are identical to those obtained by simple analyticestimate or by using simulated pure CMB maps.



Autor: Pavan K. Aluri, Pramoda K. Samal, Pankaj Jain, John. P. Ralston

Fuente: https://arxiv.org/







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