Quadrant asymmetry in the angular distribution of cosmic microwave background in the<i>Planck</i>satellite data

Santos, Larissa; Cabella, P.; Villela, T.; Balbi, A.; Vittorio, N.; Wuensche, Carlos Alexandre

doi:10.1051/0004-6361/201322943

Cited by 5 publications

(4 citation statements)

References 41 publications

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“…More recently, the Planck collaboration (Planck Collaboration XXIII, 2013) repeated the analysis of Eriksen et al (2005), by computing the two-, threeand four-correlation functions of the data, and they obtained results in agreement with those provided with WMAP data. These hemispherical differences have been supported by subsequent analysis (e.g., Santos et al 2013;Akrami et al 2014).…”

Section: Introductionmentioning

confidence: 54%

Searching for a dipole modulation in the large-scale structure of the Universe

Fernández-Cobos

Vielva

Pietrobon

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Several statistical anomalies in the CMB temperature anisotropies seem to defy the assumption of a homogeneous and isotropic universe. In particular, a dipole modulation has been detected both in WMAP and Planck data. We adapt the methodology proposed by Eriksen et al. (2007) on CMB data to galaxy surveys, tracing the largescale structure. We analyse the NRAO VLA Sky Survey (NVSS) data at a resolution of ∼ 2 • for three different flux thresholds: 2.5, 5.0 and 10.0 mJy respectively. No evidence of a dipole modulation is found. This result suggests that the origin of the dipole asymmetry found in the CMB cannot be assigned to secondary anisotropies produced at redshifts around z = 1. However, it could still have been generated at redshifts higher or lower, such as the integrated Sachs-Wolfe effect produced by the local structures. Other all-sky surveys, like the infrared WISE catalogue, could help to explore with a high sensitivity a redshift interval closer than the one probed with NVSS.

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Section: Introductionmentioning

confidence: 54%

Searching for a dipole modulation in the large-scale structure of the Universe

Fernández-Cobos

Vielva

Pietrobon

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…HPA attracted significant attention from the cosmology community, which was estimated using a variety of methods, see for example Ref. [5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]. Many explanations were also put forth to explain this anomaly with no final conclusion.…”

Section: Introductionmentioning

confidence: 99%

Power asymmetry in CMB polarization maps from PLANCK : a local variance analysis

Aluri¹,

Shafieloo²

2017

Preprint

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A persistent signal of power asymmetry on opposite hemispheres of CMB sky was seen in full-sky temperature measurements made so far. This asymmetry was seen in microwave sky from WMAP as well as PLANCK satellites, and calls for attention the larger question of statistical isotropy, one of the foundational principles of modern cosmology. In this work we present an analysis of polarized CMB maps from PLANCK 2015 full mission data. We apply the local variance estimator on low resolution E−mode maps from PLANCK 2015 polarization Commander solution. We find a significant hemispherical power asymmetry in polarization data on large angular scales, at the level of ∼ 2.6 − 3.9% depending on the galactic mask, and the circular disc radius used for computing local variance maps. However the direction is found to be pointing broadly towards CMB kinetic dipole direction. Precise measurements of CMB polarization in future will shed light on this apparent discrepancy in the anisotropy axis seen in temperature and polarized CMB sky, and likely influence of systematics on our findings.

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“…Other violations of isotropy were soon announced in WMAP data, including an alignment of the low order multipoles (Bielewicz et al, 2004;Schwarz et al, 2004;de Oliveira-Costa et al, 2004;Bielewicz et al, 2005;Land & Magueijo, 2005;Copi et al, 2006;Abramo et al, 2006;Gruppuso & Burigana, 2009;Frommert & Ensslin, 2010), the cold spot (Vielva et al, 2004;Cruz et al, 2005Cruz et al, , 2007Vielva, P., 2010), the parity asymmetry (Kim & Naselsky, 2010;Gruppuso et al, 2011;Aluri & Jain, 2012;Hansen et al, 2012;Naselsky et al , 2012;Zhao, 2014) and the North-South asymmetry (Eriksen et al, 2004a;Hansen et al, 2004a;Eriksen et al, 2004b;Hansen et al, 2004b;Donoghue et al, 2005;Hoftuft et al, 2009;Paci et al, 2010;Pietrobon et al, 2010;Vielva et al, 2010). Closely related to the North-South asymmetry is the power asymmetry found between different quadrants of the CMB sky (Santos et al, 2012(Santos et al, , 2014. Please give a shorter version with: \authorrunning and/or \titilerunning prior to \maketitle Most of the anomalies found in previous CMB observations were confirmed by Planck data suggesting that they are not due to systematic effects in the instruments.…”

Section: Introductionmentioning

confidence: 89%

“…Other violations of isotropy were soon announced in WMAP data, including an alignment of the loworder multipoles (Bielewicz et al 2004(Bielewicz et al , 2005Schwarz et al 2004;Copi et al 2004Copi et al , 2006de Oliveira-Costa et al 2004;Land & Magueijo 2005;Abramo et al 2006;Gruppuso & Burigana 2009;Frommert & Ensslin 2010), the cold spot (Vielva et al 2004;Cruz et al 2005Cruz et al , 2007Vielva 2010), the parity asymmetry (Kim & Naselsky 2010;Gruppuso et al 2011;Aluri & Jain 2012;Hansen et al 2012;Naselsky et al 2012;Zhao 2014), and the north-south asymmetry (Eriksen et al 2004a,b;Hansen et al 2004a,b;Donoghue et al 2005;Hoftuft et al 2009;Paci et al 2010;Pietrobon et al 2010;Vielva et al 2010). Closely related to the north-south asymmetry is the power asymmetry found between different quadrants of the CMB sky (Santos et al 2012(Santos et al , 2014.…”

Section: Introductionmentioning

confidence: 99%

Influence ofPlanckforeground masks in the large angular scale quadrant CMB asymmetry

Santos

Cabella

Villela

et al. 2015

A&A

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Context. 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.

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Quadrant asymmetry in the angular distribution of cosmic microwave background in thePlancksatellite data

Cited by 5 publications

References 41 publications

Searching for a dipole modulation in the large-scale structure of the Universe

Searching for a dipole modulation in the large-scale structure of the Universe

Power asymmetry in CMB polarization maps from PLANCK : a local variance analysis

Influence ofPlanckforeground masks in the large angular scale quadrant CMB asymmetry

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