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arXiv · 1309.7905

Modelling the relative velocities of isolated pairs of galaxies

V. Gonzalez-Perez·E. Jennings·M. -C. Cousinou·S. Escoffier·A. Tilquin·A. Ealet
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Abstract

We study the comoving relative velocities, v12, of model isolated galaxy pairs at z=0.5. For this purpose, we use the predictions from the GALFORM semi-analytical model of galaxy formation and evolution based on a Lambda cold dark matter cosmology consistent with the results from WMAP7. In real space, we find that isolated pairs of galaxies are predicted to form an angle t with the line-of-sight that is uniformily distributed as expected if the Universe is homogeneous and isotropic. We also find that isolated pairs of galaxies separated by a comoving distance between 1 and 3 Mpc/h are predicted to have =0. For galaxies in this regime, the distribution of the angle t is predicted to change minimally from real to redshift space, with a change smaller than 5% in . However, the distances defining the comoving regime strongly depends on the applied isolation criteria.

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V. Gonzalez-Perez, E. Jennings, M. -C. Cousinou, S. Escoffier, A. Tilquin, A. Ealet. 2013-09-30. Modelling the relative velocities of isolated pairs of galaxies. https://arxiv.org/abs/1309.7905

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