Year: 2018
Type: article
Abstract: We construct an analytic model for the void-galaxy cross-correlation function that enables theoretical predictions of the dipole signal produced dominantly by the gravitational redshift within voids for the first time. By extending a theoretical formulation for the redshift-space distortion of galaxies to include the second order terms of the galaxy peculiar velocity $\mathbit{v}$ and the gravitational potential, we formulate the void-galaxy cross-correlation function multipoles in the redshift space, the monopole ${\ensuremath{\xi}}_{0}^{(s)}$, dipole ${\ensuremath{\xi}}_{1}^{(s)}$, and quadrupole ${\ensuremath{\xi}}_{2}^{(s)}$. We find that the dipole ${\ensuremath{\xi}}_{1}^{(s)}$ is dominated by the gravitational redshift, which provides a unique opportunity to detect the gravitational potential of voids. Thus, for the dipole ${\ensuremath{\xi}}_{1}^{(s)}(s)$, the gravitational redshift is crucial. Although the higher order effect is almost negligible on the monopole ${\ensuremath{\xi}}_{0}^{(s)}$, it has an influence on the quadrupole ${\ensuremath{\xi}}_{2}^{(s)}$. The effects from the random velocity of galaxies and the definition of the void center on the dipole signal are also discussed. Our model offers a new theoretical probe for the detection of gravitational redshift with voids and further tests on cosmology and gravity.
Authors: Yue Nan, Kazuhiro Yamamoto
Institution: Hiroshima University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2804080805