@Article{SantosCabeVillZhao:2015:InPlFo,
author = "Santos, L. and Cabella, P. and Villela, Thyrso and Zhao, W.",
affiliation = "{University of Sciences and Technology of China} and {Universita
di Roma} and {Instituto Nacional de Pesquisas Espaciais (INPE)}
and {Chinese Academy of Sciences}",
title = "Influence of Planck foreground masks in the large angular scale
quadrant CMB asymmetry",
journal = "Astronomy \& Astrophysics",
year = "2015",
volume = "584",
number = "A115",
month = "Dec.",
keywords = "Cosmic background radiation, Cosmology: observations, Methods:
data analysis, Methods: statistical.",
abstract = "The measured cosmic microwave background (CMB) angular
distribution shows high consistency with the \ΛCDM model,
which predicts cosmological isotropy as one of its fundamental
characteristics. However, isotropy violations were reported in CMB
temperature maps of the Wilkinson Microwave Anisotropy Probe
(WMAP) and confirmed by Planck satellite data. Aims. Our purpose
is to investigate the influence of different sky cuts (masks)
employed in the analysis of CMB angular distribution, in
particular in the excess of power in the southeastern quadrant
(SEQ) and the lack of power in the northeastern quadrant (NEQ),
found in both WMAP and Planck data. Methods. We compared the
two-point correlation function (TPCF) computed for each quadrant
of the CMB foreground-cleaned temperature maps to 1000 Monte Carlo
(MC) simulations generated assuming the \ΛCDM best-fit power
spectrum using four different masks, from the least to the most
severe one: mask-rulerminimal, UT78, U73, and U66. In addition to
the quadrants and for a better understanding of these anomalies,
we computed the TPCF using the mask-rulerminimal for circular
regions in the map where the excess and lack of power are present.
We also compared, for completeness, the effect of Galactic cuts
(+/-10, 20, 25, and 30 degrees above/below the Galactic plane) in
the TPCF calculations as compared to the MC simulations. Results.
We found consistent results for three masks, namely
mask-rulerminimal, U73, and U66. The results indicate that the
excess of power in the SEQ tends to vanish as the portion of the
sky covered by the mask increases and the lack of power in the NEQ
remains virtually unchanged. A different result arises for the
newly released UT78 Planck mask. When this mask is applied, the
NEQ is no longer anomalous. On the other hand, the excess of power
in the SEQ becomes the most significant one among the masks.
Nevertheless, the asymmetry between the SEQ and NEQ is independent
of the mask and it disagrees with the isotropic model with at
least 95% C.L. Conclusions. We find that UT78 disagrees with the
other analyzed masks, especially when considering the SEQ and the
NEQ individual analysis. Most important, the use of UT78 washes
out the anomaly in the NEQ. Furthermore, we find an excess of
kurtosis, compared with simulations, in the NEQ for the regions
not masked by UT78 but masked by the other masks, indicating that
the previous result could be due to unremoved residual foregrounds
by UT78.",
doi = "10.1051/0004-6361/201526713",
url = "http://dx.doi.org/10.1051/0004-6361/201526713",
issn = "0004-6361 and 1432-0746",
language = "en",
targetfile = "santos.pdf",
urlaccessdate = "27 abr. 2024"
}