Events at Physics |
Events on Thursday, October 10th, 2013
- Astronomy Colloquium
- Constraining the Cosmological Evolution of Galaxies Using Bars
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall
- Speaker: Kartik Sheth, NRAO
- Abstract: Stellar bars are a key signpost in the evolutionary history of a disk
galaxy. When a disk is sufficiently massive, dynamically cold and
rotationally supported, and sufficient time has elapsed for the
baryonic matter to exchange energy and angular momentum with the dark
matter halo or the outer disk, the formation of a bar is inevitable.
Therefore understanding the evolution of the bar fraction as a
function of the host galaxy properties and as a function of redshift
provides important clues to the evolutionary history of galaxies. I
will present the latest results on local bars from the Spitzer Survey
of Stellar Structure in Galaxies (S4G) and discuss the observations
for the declining bar fraction with redshift from the COSMOS survey.
A plausible reason for the decline in the bar fraction may be that
galaxy disks were too dynamically hot to host bars at higher redshift
which we have investigated using the DEEP2 / AEGIS data. Together
these data are beginning to provide a coherent and consistent picture
for the assembly history of disks on the Hubble sequence. Using ALMA
we are also studying the evolution of the molecular gas content (and
associated star formation) as a function of redshift and in greater
detail with spatially resolved observations of nearby spirals. I will
describe the latest results of our on-going investigations on galaxy
evolution and star formation with ALMA.