Award Date

Spring 2010

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Astronomy

Department

Physics and Astronomy

Advisor 1

Kentaro Nagamine, Committee Chair

First Committee Member

Bing Zhang

Second Committee Member

Daniel Proga

Graduate Faculty Representative

Balakrishnan Naduvalath

Number of Pages

78

Abstract

PART I

We calculate the cross-correlation function (CCF) between damped Ly-alpha systems (DLAs) and Lyman break galaxies (LBGs) using cosmological hydrodynamic simulations at z = 3. We compute the CCF with two different methods. First, we assume that there is one DLA in each dark matter halo if its DLA cross section is non-zero. In our second approach we weight the pair-count by the DLA cross section of each halo, yielding a cross-section-weighted CCF. We also compute the angular CCF for direct comparison with observations. Finally, we calculate the auto-correlation functions of LBGs and DLAs, and their bias against the dark matter distribution. For these different approaches, we consistently find that there is good agreement between our simulations and observational measurements by Cooke et al. (2006a) and Adelberger et al. (2005). Our results thus confirm that the spatial distribution of LBGs and DLAs can be well described within the framework of the concordance Lambda-CDM model. We find that the correlation strengths of LBGs and DLAs are consistent with the actual observations, and in the case of LBGs it is higher than would be predicted by low-mass galaxy merger models.

PART II

We present theoretical computational results of magnitudes, luminosity functions, galaxy number counts, and redshift distribution in the 3.6, 4.5, 5.8, and 8.0 µms of IRAC and 24, 70, and 160 µms of MIPS bands using cosmological hydrodynamic simulations. We combine GADGET-3 with GRASIL spectrophotometic code to compute galaxy spectral energy distribution. We compare our luminosity function (IRAC: 8µm and MIPS: 24µm) results with observational and sampling data (Caputi et al., 2007; Rodighiero et al., 2009) from the Spitzer Space Telescope. We find that there is reliable agreement with their results.

Keywords

Cross-correlation functions; Damped Ly-α systems (DLA); Low-mass galaxies; Lyman break galaxies (LBG); Simulations

Disciplines

Astrophysics and Astronomy | External Galaxies

Language

English


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