Accueil > Séminaires d’Astrophysique > Morphological Evolution from z 2 in the COSMOS Field from Ks Band Seeing Limited Imaging

 

Morphological Evolution from z 2 in the COSMOS Field from Ks Band Seeing Limited Imaging

Marc Huertas (LESIA)

Par Stephane Charpinet - 6/10/2008

 

Séminaires d’Astrophysique

de l’Observatoire Midi-Pyrénées


Séminaire de

Marc HUERTAS

(LESIA)

Mercredi 8 Octobre 2008 à 11h

OMP, salle Coriolis


Morphological Evolution from z 2 in the COSMOS Field from Ks Band Seeing Limited Imaging

We present the morphological classification in two broad types (late and early) of 50000 galaxies in the COSMOS field. Galaxies are observed in the near-infrared (Ks band) at a median redshift of z 0.8 using WirCam at CFHT. These data are particularly interesting because K-band data have the advantage of probing old stellar populations in the rest-frame for z<2, enabling a determination of galaxy morphological types unaffected by recent star formation. Moreover, no space data in this wavelength range are available today. Galaxies are classified with a new non-parametric method (GalSVM, http://www.lesia.obspm.fr/ huertas/galsvm.html) based on support vector machines. We show that a qualitative separation in two main morphological types can be obtained with an error lower than 20% even on seeing-limited images. We therefore obtain for the first time rest-frame I band morphologies based on structural parameters up to z 2. We investigate the redshift distribution per morphological type up to z 2 and compare to the same distribution obtained with rest-frame B band morphologies (HST/ACS).

 

 

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Bibliotheque

Laboratoire Astrophysique de Toulouse - Tarbes (UMR5572)

CNRS (Midi-Pyrénées)

Univ. Paul Sabatier

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