Removing baryon-acoustic-oscillation peak shifts with local density transforms

Nuala McCullagh, Mark C. Neyrinck, I. Szapudi, Alexander S. Szalay

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Large-scale bulk flows in the universe distort the initial density field, broadening the baryon-acoustic-oscillation (BAO) feature that was imprinted when baryons were strongly coupled to photons. Additionally, there is a small shift inward in the peak of the conventional overdensity correlation function, a mass-weighted statistic. This shift occurs when high-density peaks move toward each other. We explore whether this shift can be removed by applying to the density field a transform (such as a logarithm) that gives fairer statistical weight to fluctuations in underdense regions. Using configuration-space perturbation theory in the Zel'dovich approximation, we find that the log-density correlation function shows a much smaller inward shift in the position of the BAO peak at low redshift than is seen in the overdensity correlation function. We also show that if the initial, Lagrangian density of matter parcels could be estimated at their Eulerian positions, giving a displaced-initial-density field, its peak shift would be even smaller. In fact, a transformed field that accentuates underdensities, such as the reciprocal of the density, pushes the peak the other way, outward. In our model, these shifts in the peak position can be attributed to shift terms, involving the derivative of the linear correlation function, that entirely vanish in this displaced-initial-density field.

Original languageEnglish
Article numberL14
JournalAstrophysical Journal Letters
Volume763
Issue number1
DOIs
Publication statusPublished - Jan 20 2013

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baryons
transform
acoustics
oscillation
oscillations
shift
logarithms
universe
perturbation theory
perturbation
statistics
photons
configurations
approximation

Keywords

  • cosmology: theory
  • large-scale structure of universe

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Removing baryon-acoustic-oscillation peak shifts with local density transforms. / McCullagh, Nuala; Neyrinck, Mark C.; Szapudi, I.; Szalay, Alexander S.

In: Astrophysical Journal Letters, Vol. 763, No. 1, L14, 20.01.2013.

Research output: Contribution to journalArticle

McCullagh, Nuala ; Neyrinck, Mark C. ; Szapudi, I. ; Szalay, Alexander S. / Removing baryon-acoustic-oscillation peak shifts with local density transforms. In: Astrophysical Journal Letters. 2013 ; Vol. 763, No. 1.
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