Evidence for anisotropy of cosmic acceleration
Observations reveal a “bulk flow” in the local Universe which is faster and extends to much larger scales than are expected around a typical observer in the standard ΛCDM cosmology. This is expected to result in a scale-dependent dipolar modulation of the acceleration of the expansion rate inferred...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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EDP Sciences
2019
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| _version_ | 1797097470255169536 |
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| author | Colin, J Mohayaee, R Rameez, M Sarkar, S |
| author_facet | Colin, J Mohayaee, R Rameez, M Sarkar, S |
| author_sort | Colin, J |
| collection | OXFORD |
| description | Observations reveal a “bulk flow” in the local Universe which is faster and extends to much larger scales than are expected around a typical observer in the standard ΛCDM cosmology. This is expected to result in a scale-dependent dipolar modulation of the acceleration of the expansion rate inferred from observations of objects within the bulk flow. From a maximum-likelihood analysis of the Joint Light-curve Analysis catalogue of Type Ia supernovae, we find that the deceleration parameter, in addition to a small monopole, indeed has a much bigger dipole component aligned with the cosmic microwave background dipole, which falls exponentially with redshift z: q0 = qm + qd.n̂ exp(-z/S). The best fit to data yields qd = −8.03 and S = 0.0262 (⇒d ∼ 100 Mpc), rejecting isotropy (qd = 0) with 3.9σ statistical significance, while qm = −0.157 and consistent with no acceleration (qm = 0) at 1.4σ. Thus the cosmic acceleration deduced from supernovae may be an artefact of our being non-Copernican observers, rather than evidence for a dominant component of “dark energy” in the Universe. |
| first_indexed | 2024-03-07T04:55:58Z |
| format | Journal article |
| id | oxford-uuid:d69e2308-e24c-44ce-8109-e85b5c4ee587 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T04:55:58Z |
| publishDate | 2019 |
| publisher | EDP Sciences |
| record_format | dspace |
| spelling | oxford-uuid:d69e2308-e24c-44ce-8109-e85b5c4ee5872022-03-27T08:34:50ZEvidence for anisotropy of cosmic accelerationJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:d69e2308-e24c-44ce-8109-e85b5c4ee587EnglishSymplectic Elements at OxfordEDP Sciences2019Colin, JMohayaee, RRameez, MSarkar, SObservations reveal a “bulk flow” in the local Universe which is faster and extends to much larger scales than are expected around a typical observer in the standard ΛCDM cosmology. This is expected to result in a scale-dependent dipolar modulation of the acceleration of the expansion rate inferred from observations of objects within the bulk flow. From a maximum-likelihood analysis of the Joint Light-curve Analysis catalogue of Type Ia supernovae, we find that the deceleration parameter, in addition to a small monopole, indeed has a much bigger dipole component aligned with the cosmic microwave background dipole, which falls exponentially with redshift z: q0 = qm + qd.n̂ exp(-z/S). The best fit to data yields qd = −8.03 and S = 0.0262 (⇒d ∼ 100 Mpc), rejecting isotropy (qd = 0) with 3.9σ statistical significance, while qm = −0.157 and consistent with no acceleration (qm = 0) at 1.4σ. Thus the cosmic acceleration deduced from supernovae may be an artefact of our being non-Copernican observers, rather than evidence for a dominant component of “dark energy” in the Universe. |
| spellingShingle | Colin, J Mohayaee, R Rameez, M Sarkar, S Evidence for anisotropy of cosmic acceleration |
| title | Evidence for anisotropy of cosmic acceleration |
| title_full | Evidence for anisotropy of cosmic acceleration |
| title_fullStr | Evidence for anisotropy of cosmic acceleration |
| title_full_unstemmed | Evidence for anisotropy of cosmic acceleration |
| title_short | Evidence for anisotropy of cosmic acceleration |
| title_sort | evidence for anisotropy of cosmic acceleration |
| work_keys_str_mv | AT colinj evidenceforanisotropyofcosmicacceleration AT mohayaeer evidenceforanisotropyofcosmicacceleration AT rameezm evidenceforanisotropyofcosmicacceleration AT sarkars evidenceforanisotropyofcosmicacceleration |