Séminaire Univers / |
| « Redshifts measurements by on-sky cross-correlations » |
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Vivien Scottez |
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In the context of large redshifts surveys, like the Euclid mission, we developed a new way to measure the distances of extragalactic objects. I will, first, explain how we can extract the redshift distribution of a sample of galaxies by measuring its angular cross-correlation with a set of reference. Insisting on the fundamental difference between this clustering redshift method and photometric redshift I will present, and discuss, first results on SDSS and CFHTLS/VIPERS data. Since this method only needs on sky positions of objects (RA & DEC) it is faster and cheaper than photometric redshifts. In some cases it leads to even better results. This lets us think that in the coming years such measurements will be largely used to check and/or replace photometric redshifts.
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mardi 2 juin 2015 - 11:15 Salle 281 Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |