Local group velocity versus gravity

Nonlinear effects

Pawel Cieciela̧g, Michał Chodorowski, Andrzej Kudlicki

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

We use numerical simulations to study the relation between the velocity of the Local Group (LG) and its gravitational acceleration. This relation serves as a test for the kinematic origin of the CMB dipole and as a method for estimating ß= Ω0.6/b. We calculate the misalignment angle between the two vectors and compare it to the observed value for the PSCz survey. The latter value is beyond the upper limit of the 90% confidence interval for the angle; therefore, the nonlinear effects are unlikely to be responsible for the whole observed misalignment. We also study the relation between the amplitudes of the LG velocity and gravity vectors. In an Ω = 1 Universe, the smoothed gravity of the LG turns out to be a biased low estimator of the LG (unsmoothed) velocity. In an Ω = 0.3 Universe, the estimator is biased high. The discussed biases are, however, only a few per cent, thus the linear theory works to good accuracy. The gravity-based estimator of the LG velocity has also a scatter that limits the precision of the estimate of β in the LG velocity-gravity comparisons. The random error of β due to nonlinear effects amounts to several per cent.

Original languageEnglish (US)
Pages (from-to)103-115
Number of pages13
JournalActa Astronomica
Volume51
Issue number2
StatePublished - 2001
Externally publishedYes

Fingerprint

group velocity
gravity
gravitation
estimators
misalignment
universe
random errors
confidence interval
kinematics
effect
confidence
estimating
dipoles
intervals
simulation
estimates

Keywords

  • Cosmology: theory
  • Dark matter
  • Large scale
  • Methods: numerical
  • Structure of Universe

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Cieciela̧g, P., Chodorowski, M., & Kudlicki, A. (2001). Local group velocity versus gravity: Nonlinear effects. Acta Astronomica, 51(2), 103-115.

Local group velocity versus gravity : Nonlinear effects. / Cieciela̧g, Pawel; Chodorowski, Michał; Kudlicki, Andrzej.

In: Acta Astronomica, Vol. 51, No. 2, 2001, p. 103-115.

Research output: Contribution to journalArticle

Cieciela̧g, P, Chodorowski, M & Kudlicki, A 2001, 'Local group velocity versus gravity: Nonlinear effects', Acta Astronomica, vol. 51, no. 2, pp. 103-115.
Cieciela̧g P, Chodorowski M, Kudlicki A. Local group velocity versus gravity: Nonlinear effects. Acta Astronomica. 2001;51(2):103-115.
Cieciela̧g, Pawel ; Chodorowski, Michał ; Kudlicki, Andrzej. / Local group velocity versus gravity : Nonlinear effects. In: Acta Astronomica. 2001 ; Vol. 51, No. 2. pp. 103-115.
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