Examining statistical isotropy of CMB low multipoles from Planck PR4 data
Low multipoles (l) in cosmic microwave background (CMB) temperature anisotropies have shown some ‘peculiarities’ when examined since the release of the full sky CMB maps, using a variety of tests. In this paper, we concern ourselves with the very first peculiarities seen in CMB data viz., a breakdow...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-01-01
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| Series: | Physics Letters B |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0370269322007274 |
| _version_ | 1811211413287337984 |
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| author | Pavan Kumar Aluri Sanjeet Kumar Patel |
| author_facet | Pavan Kumar Aluri Sanjeet Kumar Patel |
| author_sort | Pavan Kumar Aluri |
| collection | DOAJ |
| description | Low multipoles (l) in cosmic microwave background (CMB) temperature anisotropies have shown some ‘peculiarities’ when examined since the release of the full sky CMB maps, using a variety of tests. In this paper, we concern ourselves with the very first peculiarities seen in CMB data viz., a breakdown of statistical isotropy in the form of axiality and planarity of these low-l modes, and preferred alignments among them. We scrutinize the latest CMB data from ESA's Planck mission, PR4, to evaluate the current status of these deviations. We employ the Power tensor method which allows an invariant characterization of the distribution of power in a given multipole, and apply it to probe the first sixty multipoles i.e., l=2 to 61. We find that there are significant number of modes that are intrinsically anisotropic with a cumulative probability of 0.3%. However since the planarity study reveals that those modes that are unusually planar are subset of these anisotropic modes, we conclude that they may not be intrinsically planar. The quadrupole is still well aligned with the octopole. Besides, l=3, higher multipoles aligned with quadrupole are found to be insignificant. Interestingly, the collective alignment axis of the first sixty multipoles is found to be broadly closer to the axis of dipole, quadrupole, octopole and other modes aligned with l=2. |
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| format | Article |
| id | doaj.art-77dfe27621ab41ab9d769009450b53a9 |
| institution | Directory Open Access Journal |
| issn | 0370-2693 |
| language | English |
| last_indexed | 2024-04-12T05:12:35Z |
| publishDate | 2023-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Physics Letters B |
| spelling | doaj.art-77dfe27621ab41ab9d769009450b53a92022-12-22T03:46:43ZengElsevierPhysics Letters B0370-26932023-01-01836137593Examining statistical isotropy of CMB low multipoles from Planck PR4 dataPavan Kumar Aluri0Sanjeet Kumar Patel1Corresponding author.; Department of Physics, Indian Institute of Technology (BHU), Varanasi - 221005, IndiaDepartment of Physics, Indian Institute of Technology (BHU), Varanasi - 221005, IndiaLow multipoles (l) in cosmic microwave background (CMB) temperature anisotropies have shown some ‘peculiarities’ when examined since the release of the full sky CMB maps, using a variety of tests. In this paper, we concern ourselves with the very first peculiarities seen in CMB data viz., a breakdown of statistical isotropy in the form of axiality and planarity of these low-l modes, and preferred alignments among them. We scrutinize the latest CMB data from ESA's Planck mission, PR4, to evaluate the current status of these deviations. We employ the Power tensor method which allows an invariant characterization of the distribution of power in a given multipole, and apply it to probe the first sixty multipoles i.e., l=2 to 61. We find that there are significant number of modes that are intrinsically anisotropic with a cumulative probability of 0.3%. However since the planarity study reveals that those modes that are unusually planar are subset of these anisotropic modes, we conclude that they may not be intrinsically planar. The quadrupole is still well aligned with the octopole. Besides, l=3, higher multipoles aligned with quadrupole are found to be insignificant. Interestingly, the collective alignment axis of the first sixty multipoles is found to be broadly closer to the axis of dipole, quadrupole, octopole and other modes aligned with l=2.http://www.sciencedirect.com/science/article/pii/S0370269322007274CosmologyCMBTemperature anisotropiesStatistical isotropyPlanck PR4 |
| spellingShingle | Pavan Kumar Aluri Sanjeet Kumar Patel Examining statistical isotropy of CMB low multipoles from Planck PR4 data Physics Letters B Cosmology CMB Temperature anisotropies Statistical isotropy Planck PR4 |
| title | Examining statistical isotropy of CMB low multipoles from Planck PR4 data |
| title_full | Examining statistical isotropy of CMB low multipoles from Planck PR4 data |
| title_fullStr | Examining statistical isotropy of CMB low multipoles from Planck PR4 data |
| title_full_unstemmed | Examining statistical isotropy of CMB low multipoles from Planck PR4 data |
| title_short | Examining statistical isotropy of CMB low multipoles from Planck PR4 data |
| title_sort | examining statistical isotropy of cmb low multipoles from planck pr4 data |
| topic | Cosmology CMB Temperature anisotropies Statistical isotropy Planck PR4 |
| url | http://www.sciencedirect.com/science/article/pii/S0370269322007274 |
| work_keys_str_mv | AT pavankumaraluri examiningstatisticalisotropyofcmblowmultipolesfromplanckpr4data AT sanjeetkumarpatel examiningstatisticalisotropyofcmblowmultipolesfromplanckpr4data |