CORE
🇺🇦Â
 make metadata, not war
Services
Services overview
Explore all CORE services
Access to raw data
API
Dataset
FastSync
Content discovery
Recommender
Discovery
OAI identifiers
OAI Resolver
Managing content
Dashboard
Bespoke contracts
Consultancy services
Support us
Support us
Membership
Sponsorship
Community governance
Advisory Board
Board of supporters
Research network
About
About us
Our mission
Team
Blog
FAQs
Contact us
research
Detection of the ISW effect and corresponding dark energy constraints made with directional spherical wavelets
Authors
A. N. Lasenby
Crittenden
+5Â more
E. Martinez-Gonzalez
J. D. McEwen
M. P. Hobson
P. Vielva
Wiaux
Publication date
17 February 2006
Publisher
'Wiley'
Doi
Cite
View
on
arXiv
Abstract
Using a directional spherical wavelet analysis we detect the integrated Sachs-Wolfe (ISW) effect, indicated by a positive correlation between the first-year Wilkinson Microwave Anisotropy Probe (WMAP) and NRAO VLA Sky Survey (NVSS) data. Detections are made using both a directional extension of the spherical Mexican hat wavelet and the spherical butterfly wavelet. We examine the possibility of foreground contamination and systematics in the WMAP data and conclude that these factors are not responsible for the signal that we detect. The wavelet analysis inherently enables us to localise on the sky those regions that contribute most strongly to the correlation. On removing these localised regions the correlation that we detect is reduced in significance, as expected, but it is not eliminated, suggesting that these regions are not the sole source of correlation between the data. This finding is consistent with predictions made using the ISW effect, where one would expect weak correlations over the entire sky. In a flat universe the detection of the ISW effect provides direct and independent evidence for dark energy. We use our detection to constrain dark energy parameters by deriving a theoretical prediction for the directional wavelet covariance statistic for a given cosmological model. Comparing these predictions with the data we place constraints on the equation-of-state parameter
w
w
w
and the vacuum energy density
Ω
Λ
\Omega_\Lambda
Ω
Λ
​
. We also consider the case of a pure cosmological constant, i.e.
w
=
−
1
w=-1
w
=
−
1
. For this case we rule out a zero cosmological constant at greater than the 99.9% significance level. All parameter estimates that we obtain are consistent with the standand cosmological concordance model values.Comment: 16 pages, 13 figures; replaced to match version accepted by MNRA
Similar works
Full text
Open in the Core reader
Download PDF
Available Versions
Crossref
See this paper in CORE
Go to the repository landing page
Download from data provider
Last time updated on 04/12/2019