Testing the Friedmannian magnitude-redshift relation with SNIa data

Abstract

Standard cosmology is constructed upon the (generally implicit) assumption of the ``large scale'' homogeneity of our Universe. Now, structures are observed at scales which become larger and larger as the observational distances increase. However, the homogeneous Friedmann-Lemaitre-Robertson-Walker model remains a cosmological paradigm, and Friedmannian relations are usually used to work out the model, implicitly assuming that the homogeneity assumption is valid at the studied scales. This has been the way the concordance (Lambda-CDM) model came out from the analyses of the SNIa data. Since this model implies the validity of the Friedmannian magnitude-redshift relation at the range of redshifts spaned by the supernovae surveys, it has been proposed some years ago a very simple test of this possible validity, provided the SNIa should be confirmed as standard candles. Since we can hope that the redshifts of the supernovae which will be observed in the years to come will allow such a test to be performed, it would be interesting to find inside the SNIa community some collaborators ready to perform the test.