Asymmetric galaxy correlation functions
- Phys.Rev.D 89 (2014) 8, 083535
- Published: Apr 30, 2014
- 1309.1321 [astro-ph.CO]
Citations per year
We study the two-point cross-correlation function between two populations of galaxies: for instance, a bright population and a faint population. We show that this cross-correlation is asymmetric under the exchange of the line-of-sight coordinate of the galaxies, i.e. that the correlation is different if the bright galaxy is in front of, or behind, the faint galaxy. We give an intuitive, quasi-Newtonian derivation of all the effects that contribute to such an asymmetry in large-scale structure: gravitational redshift, Doppler shift, lensing, light-cone, evolution and Alcock-Paczynski effects; interestingly, the gravitational redshift term is exactly canceled by some of the others, assuming geodesic motion. Most of these effects are captured by previous calculations of general relativistic corrections to the observed galaxy density fluctuation; the asymmetry arises from terms that are suppressed by the ratio (
- v1: 22 pages, 12 figures; v2: discussion about the Alcock-Paczynski effect and about dust extinction added, new figure 13 explaining the sign of the dipole, discussion in appendix E about the comparison with clusters measurement extended. This version matches the published version
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