DIRECTIONAL DEPENDENCE OF {Lambda}CDM COSMOLOGICAL PARAMETERS

Axelsson, M.; Fantaye, Y.; Hansen, F. K.; Eriksen, H. K.; Banday, A. J.

doi:10.1088/2041-8205/773/1/L3

Title: DIRECTIONAL DEPENDENCE OF {Lambda}CDM COSMOLOGICAL PARAMETERS

Full Record
Other Related Research

Abstract

We study hemispherical power asymmetry in the Wilkinson Microwave Anisotropy Probe 9 yr data. We analyze the combined V- and W-band sky maps, after application of the KQ85 mask, and find that the asymmetry is statistically significant at the 3.4{sigma} confidence level for l = 2-600, where the data are signal-dominated, with a preferred asymmetry direction (l, b) = (227, -27). Individual asymmetry axes estimated from six independent multipole ranges are all consistent with this direction. Subsequently, we estimate cosmological parameters on different parts of the sky and show that the parameters A{sub s} , n{sub s} , and {Omega}{sub b} are the most sensitive to this power asymmetry. In particular, for the two opposite hemispheres aligned with the preferred asymmetry axis, we find n{sub s} = 0.959 {+-} 0.022 and n{sub s} = 0.989 {+-} 0.024, respectively.

Authors:

Axelsson, M.; Fantaye, Y.; Hansen, F. K.; Eriksen, H. K. ^[1]; Banday, A. J. ^[2]

Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway)
Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France)

Publication Date:: Sat Aug 10 00:00:00 EDT 2013

OSTI Identifier:: 22140251

Resource Type:: Journal Article

Journal Name:: Astrophysical Journal Letters

Additional Journal Information:: Journal Volume: 773; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205

Country of Publication:: United States

Language:: English

Subject:: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; ASYMMETRY; BACKGROUND RADIATION; COSMOLOGICAL CONSTANT; COSMOLOGY; MICROWAVE RADIATION; PROBES

Citation Formats


                    Axelsson, M., Fantaye, Y., Hansen, F. K., Eriksen, H. K., Banday, A. J., and Gorski, K. M., E-mail: magnus.axelsson@astro.uio.no, E-mail: y.t.fantaye@astro.uio.no. DIRECTIONAL DEPENDENCE OF {Lambda}CDM COSMOLOGICAL PARAMETERS.  United States: N. p., 2013. 
        Web.  doi:10.1088/2041-8205/773/1/L3.

Copy to clipboard


                    Axelsson, M., Fantaye, Y., Hansen, F. K., Eriksen, H. K., Banday, A. J., & Gorski, K. M., E-mail: magnus.axelsson@astro.uio.no, E-mail: y.t.fantaye@astro.uio.no. DIRECTIONAL DEPENDENCE OF {Lambda}CDM COSMOLOGICAL PARAMETERS.  United States.  https://doi.org/10.1088/2041-8205/773/1/L3

Copy to clipboard


                    Axelsson, M., Fantaye, Y., Hansen, F. K., Eriksen, H. K., Banday, A. J., and Gorski, K. M., E-mail: magnus.axelsson@astro.uio.no, E-mail: y.t.fantaye@astro.uio.no. 2013.  
        "DIRECTIONAL DEPENDENCE OF {Lambda}CDM COSMOLOGICAL PARAMETERS".  United States.  https://doi.org/10.1088/2041-8205/773/1/L3.

Copy to clipboard


                    
@article{osti_22140251,

  title        = {DIRECTIONAL DEPENDENCE OF {Lambda}CDM COSMOLOGICAL PARAMETERS},

  author       = {Axelsson, M. and Fantaye, Y. and Hansen, F. K. and Eriksen, H. K. and Banday, A. J. and Gorski, K. M., E-mail: magnus.axelsson@astro.uio.no, E-mail: y.t.fantaye@astro.uio.no},

  abstractNote = {We study hemispherical power asymmetry in the Wilkinson Microwave Anisotropy Probe 9 yr data. We analyze the combined V- and W-band sky maps, after application of the KQ85 mask, and find that the asymmetry is statistically significant at the 3.4{sigma} confidence level for l = 2-600, where the data are signal-dominated, with a preferred asymmetry direction (l, b) = (227, -27). Individual asymmetry axes estimated from six independent multipole ranges are all consistent with this direction. Subsequently, we estimate cosmological parameters on different parts of the sky and show that the parameters A{sub s} , n{sub s} , and {Omega}{sub b} are the most sensitive to this power asymmetry. In particular, for the two opposite hemispheres aligned with the preferred asymmetry axis, we find n{sub s} = 0.959 {+-} 0.022 and n{sub s} = 0.989 {+-} 0.024, respectively.},

  doi          = {10.1088/2041-8205/773/1/L3},

  url          = {https://www.osti.gov/biblio/22140251},
  journal      = {Astrophysical Journal Letters},

  issn         = {2041-8205},

  number       = 1,

  volume       = 773,

  place        = {United States},

  year         = {Sat Aug 10 00:00:00 EDT 2013},

  month        = {Sat Aug 10 00:00:00 EDT 2013}

}

Copy to clipboard

Journal Article:

https://doi.org/10.1088/2041-8205/773/1/L3

Other availability

Find in Google Scholar

Search WorldCat to find libraries that may hold this journal

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

INCREASING EVIDENCE FOR HEMISPHERICAL POWER ASYMMETRY IN THE FIVE-YEAR WMAP DATA

Journal Article Hoftuft, J; Eriksen, H; Hansen, F; ... - Astrophysical Journal

Motivated by the recent results of Hansen et al. concerning a noticeable hemispherical power asymmetry in the Wilkinson Microwave Anisotropy Probe (WMAP) data on small angular scales, we revisit the dipole-modulated signal model introduced by Gordon et al.. This model assumes that the true cosmic microwave background signal consists of a Gaussian isotropic random field modulated by a dipole, and is characterized by an overall modulation amplitude, A, and a preferred direction, p-hat. Previous analyses of this model have been restricted to very low resolution (i.e., 3.{sup 0}6 pixels, a smoothing scale of 9 deg. FWHM, and l {approx}< 40)more »« less
https://doi.org/10.1088/0004-637X/699/2/985; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Needlet detection of features in the WMAP CMB sky and the impact on anisotropies and hemispherical asymmetries

Journal Article Pietrobon, Davide; Amblard, Alexandre; Cooray, Asantha; ... - Physical Review. D, Particles Fields

We apply spherical needlets to the Wilkinson Microwave Anisotropy Probe 5-year cosmic microwave background (CMB) data set, to search for imprints of nonisotropic features in the CMB sky. We use the needlets' localization properties to resolve peculiar features in the CMB sky and to study how these features contribute to the anisotropy power spectrum of the CMB. In addition to the now well-known 'cold spot' of the CMB map in the southern hemisphere, we also find two hot spots at greater than 99% confidence level, again in the southern hemisphere and closer to the Galactic plane. While the cold spotmore »« less
https://doi.org/10.1103/PHYSREVD.78.103504
Anomalous CMB north-south asymmetry

Journal Article Bernui, Armando - Physical Review. D, Particles Fields

Several accurate analyses have revealed a statistically significant north-south ecliptic asymmetry in the large-angle correlations strength of the cosmic microwave background (CMB) radiation temperature field data from the Wilkinson Microwave Anisotropy Probe (WMAP). This asymmetry is inconsistent with the statistical isotropy expected in the concordance cosmological model {lambda}CDM. It has been suggested that a possible cause-effect relationship exists between this large-angle anisotropy and the anomalous CMB quadrupole-octopole planes alignment. In turn, this later phenomenon (or both) would be a consequence of one or more of the following undesired effects in CMB data: a systematic error in the data processing ormore »« less
https://doi.org/10.1103/PHYSREVD.78.063531
THE COSMOLOGICAL BULK FLOW: CONSISTENCY WITH {Lambda}CDM AND z {approx} 0 CONSTRAINTS ON {sigma}{sub 8} AND {gamma}

Journal Article Nusser, Adi; Davis, Marc - Astrophysical Journal

We derive estimates for the cosmological bulk flow from the SFI++ Tully-Fisher (TF) catalog. For a sphere of radius 40 h{sup -1} Mpc centered on the Milky Way, we derive a bulk flow of 333 {+-} 38 km s{sup -1} toward Galactic (l, b) = (276 deg., 14 deg.) within a 3{sup 0} 1{sigma} error. Within a radius of 100h{sup -1} Mpc we get 257 {+-} 44 km s{sup -1} toward (l, b) = (279 deg., 10 deg.) within a 6 deg. error. These directions are at 40 deg. to the Supergalactic plane, close to the apex of the motionmore »« less
https://doi.org/10.1088/0004-637X/736/2/93
A MEASUREMENT OF THE DAMPING TAIL OF THE COSMIC MICROWAVE BACKGROUND POWER SPECTRUM WITH THE SOUTH POLE TELESCOPE

Journal Article Keisler, R; Benson, B; Bleem, L; ... - Astrophysical Journal

We present a measurement of the angular power spectrum of the cosmic microwave background (CMB) using data from the South Pole Telescope (SPT). The data consist of 790 deg{sup 2} of sky observed at 150 GHz during 2008 and 2009. Here we present the power spectrum over the multipole range 650 < l < 3000, where it is dominated by primary CMB anisotropy. We combine this power spectrum with the power spectra from the seven-year Wilkinson Microwave Anisotropy Probe (WMAP) data release to constrain cosmological models. We find that the SPT and WMAP data are consistent with each other and,more »« less
https://doi.org/10.1088/0004-637X/743/1/28

Similar Records