Séminaire / Seminar GReCO |
| « What do galaxy surveys really measure? » |
|
R. Durrer |
| In large galaxy surveys which go out to redshift z=1 or more, relativistic effects, e.g. from the fact that our observations are not on a spatial hypersurface but on the past lightcone which itself is perturbed by structure formation, can no longer be neglected. I present these effects to first order in perturbation theory and propose and angular and redshift power spectrum which are both directly observable. We shall see that the complications due to the fact that we only observe on our past lightcone and that we do not truly know the distance of the observed galaxy, but just its redshift, is not only an additional difficulty, but especially a new opportunity for future galaxy surveys. |
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lundi 4 avril 2011 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |