logo observatoire

SÉMINAIRE DU LERMA
OBSERVATOIRE DE PARIS
logo lerma



Vendredi 4 juillet 2003, a 14h


77 avenue Denfert Rochereau, Paris 14



Salle de l'Atelier, Observatoire de Paris





Bars do NOT disappear at z > 0.7: NICMOS Deep Field Observations



Kartik Sheth

Caltech



Résumé : In the past decade, several optical studies have suggested that barred spirals disappear at z > 0.5--0.7. The absence of bars can severely constrain galaxy formation because bars are important signposts of the formation of cold, rotationally-supported massive disks. These studies however suffer from bandshifting and resolution affects. I discuss our recent analysis of the NICMOS HDFN which shows that there is no significant evidence for a decline in the bar fraction beyond z~0.7! The data suggest that cold, massive disks and/or large disks were present at least 7 Gyr ago (at z~1), consistent with star formation history. I will conclude by briefly reviewing a proposed study of the evolution of galaxy disks using the 2-sq. degree COSMOS ACS survey, and future observations with SIRTF and CARMA. CARMA is the new Combined Array for Research in Millimeter Astronomy.