Title: 

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



Kartk Sheth
Caltech


Abstract:


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, recent modeling work etc.  I will conclude by briefly
reviewing a proposed study of the evolution of galaxy disks using the
2-sq. degree COSMOS ACS survey, and planned observations with SIRTF,
CARMA and other ground-based observations.