Interacting galaxies and cosmological parameters

Henri Reboul (1) , J.-P. Cordoni (1)

1 GRAAL - Groupe de Recherche en Astronomie et Astrophysique du Languedoc

We propose a (physical)-geometrical method to measure Ω m• and Ω Λ• , the present rates of the density cosmological parameters for a Friedmann-Lemaître universe. The distribution of linear separations between two interacting galaxies, when both of them undergo a first massive starburst, is used as a standard of length. Statistical properties of the linear separations of such pairs of "interactivated" galaxies are estimated from the data in the Two Degree Field Galaxy Redshift Survey. Synthetic samples of interactivated pairs are generated with random orientations and a likely distribution of redshifts. The resolution of the inverse problem provides the probability densities of the retrieved cos-mological parameters. The accuracies that can be achieved by that method on Ω m• and Ω Λ• are computed depending on the size of ongoing real samples. Observational prospects are investigated as the foreseeable surface densities on the sky and magnitudes of those objects.

Mots clés: galaxies: interactions; cosmology: cosmological parameters; galaxies: starburst; surveys

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Henri Reboul, J.-P. Cordoni. Interacting galaxies and cosmological parameters. Astronomy and Astrophysics - A&A, 2006, 451 (2), pp.387-393. ⟨10.1051/0004-6361:20053879⟩. ⟨hal-02160424⟩