Evolution of galaxy structures as a function of z

This will be the last part of my thesis. I will study the rest frame K band bulge-disk luminosity function and their evolution using GALPHAT. For doing this, we do not only require the uniform sample of galaxies but also require the smooth and symmetric galaxy image. It is well known that Hubble sequence is seen upto redshift z~1. Therefore the goal is to select uniform sample of galaxies from 0<z<1 and decompose their morphology as a bulge and disk. There are several previous studies(Caputi etal 2006; Dahlen etal 2005) on the evolution of rest frame galaxy NIR band luminosity function upto z~1. However people still argue: how (much) does the luminosity function in the rest frame K band evolve as a function of z ? Because there are hidden systematic effects due to biased sample and different measures of luminosity function, it is difficult to compare different results and derive a sort of consensus on the evolution of galaxy population.

Our approach will use GALPHAT for performing the robust decomposition and the newly proposed way of measuring luminosity function based on Bayesian MCMC (Kelly etal 2008). This study will provide us, for the first time, the direct observation of bulge-disk luminosity function evolution using the robust measure of luminosity function of bulge and disk. Since the rest frame K band is the least affected by dust and minimally biased tracer of stellar mass in a galaxy, it will also give us a hint of mass assembly history of bulge and disk as a function of z.

It seems that Chandra Deep Field South is a good place to study. I can find sources in the field from other observational campaign such as COMBO-17. If coordinates and redshift are known. I can cut images and run GALPHAT. Then the questions is how smooth and symmetric galaxies are in my sample. I really need to see the galaxies to have a feeling for them.


~ by ilsangyoon on October 1, 2008.

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