COSMOLOGICAL IMPLICATIONS OF THE CMB LARGE-SCALE STRUCTURE

Persistent Link:
http://hdl.handle.net/10150/615117
Title:
COSMOLOGICAL IMPLICATIONS OF THE CMB LARGE-SCALE STRUCTURE
Author:
Melia, Fulvio ( 0000-0002-8014-0593 )
Affiliation:
The University of Arizona
Issue Date:
2014-12-01
Publisher:
IOP PUBLISHING LTD
Citation:
COSMOLOGICAL IMPLICATIONS OF THE CMB LARGE-SCALE STRUCTURE 2014, 149 (1):6 The Astronomical Journal
Journal:
The Astronomical Journal
Rights:
© 2015. The American Astronomical Society. All rights reserved.
Collection Information:
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.
Abstract:
The Wilkinson Microwave Anisotropy Probe (WMAP) and {\it Planck} {\bf may have} uncovered several anomalies in the full cosmic microwave background (CMB) sky that {\bf could indicate} possible new physics driving the growth of density fluctuations in the early Universe. These include an unusually low power at the largest scales and an apparent alignment of the quadrupole and octopole moments. In a $\Lambda$CDM model where the CMB is described by a Gaussian Random Field, the quadrupole and octopole moments should be statistically independent. {\bf The emergence of these low probability features may simply be due to posterior selections from many such possible effects, whose occurrence would therefore not be as unlikely as one might naively infer. If this is not the case, however, and if these features are not due to effects such as foreground contamination, their combined statistical significance would be equal to the product of their individual significances.} In the absence of such extraneous factors, {\bf and ignoring the biasing due to posterior selection, the missing large-angle correlations would have a probability as low as $\sim 0.1\%$ and the low-$l$ multipole alignment would be unlikely at the $\sim 4.9\%$ level; under the least favourable conditions, their simultaneous observation in the context of the standard model could then be likely at only the $\sim 0.005\%$ level.} In this paper, {\bf we explore the possibility that these features are indeed anomalous, and} show that the corresponding probability of CMB multipole alignment in the $R_{\rm h}=ct$ Universe {\bf would then be} $\sim 7-10\%$, depending on the number of large-scale Sachs-Wolfe induced fluctuations. Since the low power at the largest spatial scales is reproduced in this cosmology without the need to invoke cosmic variance, the overall likelihood of observing both of these features in the CMB is $\geq 7\%$, {\bf much more likely than in $\Lambda$CDM, if the anomalies are real.} The key physical ingredient responsible for this difference is the existence in the former of a maximum fluctuation size at the time of recombination, which is absent in the latter because of inflation.
ISSN:
1538-3881
DOI:
10.1088/0004-6256/149/1/6
Version:
Final accepted manuscript
Additional Links:
http://stacks.iop.org/1538-3881/149/i=1/a=6?key=crossref.6f3920f206d30b0889f128ad82302d8a

Full metadata record

DC FieldValue Language
dc.contributor.authorMelia, Fulvioen
dc.date.accessioned2016-06-30T00:35:24Z-
dc.date.available2016-06-30T00:35:24Z-
dc.date.issued2014-12-01-
dc.identifier.citationCOSMOLOGICAL IMPLICATIONS OF THE CMB LARGE-SCALE STRUCTURE 2014, 149 (1):6 The Astronomical Journalen
dc.identifier.issn1538-3881-
dc.identifier.doi10.1088/0004-6256/149/1/6-
dc.identifier.urihttp://hdl.handle.net/10150/615117-
dc.description.abstractThe Wilkinson Microwave Anisotropy Probe (WMAP) and {\it Planck} {\bf may have} uncovered several anomalies in the full cosmic microwave background (CMB) sky that {\bf could indicate} possible new physics driving the growth of density fluctuations in the early Universe. These include an unusually low power at the largest scales and an apparent alignment of the quadrupole and octopole moments. In a $\Lambda$CDM model where the CMB is described by a Gaussian Random Field, the quadrupole and octopole moments should be statistically independent. {\bf The emergence of these low probability features may simply be due to posterior selections from many such possible effects, whose occurrence would therefore not be as unlikely as one might naively infer. If this is not the case, however, and if these features are not due to effects such as foreground contamination, their combined statistical significance would be equal to the product of their individual significances.} In the absence of such extraneous factors, {\bf and ignoring the biasing due to posterior selection, the missing large-angle correlations would have a probability as low as $\sim 0.1\%$ and the low-$l$ multipole alignment would be unlikely at the $\sim 4.9\%$ level; under the least favourable conditions, their simultaneous observation in the context of the standard model could then be likely at only the $\sim 0.005\%$ level.} In this paper, {\bf we explore the possibility that these features are indeed anomalous, and} show that the corresponding probability of CMB multipole alignment in the $R_{\rm h}=ct$ Universe {\bf would then be} $\sim 7-10\%$, depending on the number of large-scale Sachs-Wolfe induced fluctuations. Since the low power at the largest spatial scales is reproduced in this cosmology without the need to invoke cosmic variance, the overall likelihood of observing both of these features in the CMB is $\geq 7\%$, {\bf much more likely than in $\Lambda$CDM, if the anomalies are real.} The key physical ingredient responsible for this difference is the existence in the former of a maximum fluctuation size at the time of recombination, which is absent in the latter because of inflation.en
dc.language.isoenen
dc.publisherIOP PUBLISHING LTDen
dc.relation.urlhttp://stacks.iop.org/1538-3881/149/i=1/a=6?key=crossref.6f3920f206d30b0889f128ad82302d8aen
dc.rights© 2015. The American Astronomical Society. All rights reserved.en
dc.titleCOSMOLOGICAL IMPLICATIONS OF THE CMB LARGE-SCALE STRUCTUREen
dc.typeArticleen
dc.contributor.departmentThe University of Arizonaen
dc.identifier.journalThe Astronomical Journalen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal accepted manuscripten
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