Séminaire Doctorants / Seminar PhD students |
| « Redshifts measurement by on-sky cross-correlations » |
|
Vivien Scottez |
| In the context of large redshifts survey, 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 data. Since this method only needs sky positions of objects (RA & DEC) it is faster and cheaper than photometric redshift. In some cases it even leads to 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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mercredi 26 novembre 2014 - 17:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique |
| Page web du Séminaire / Seminar's webpage |