A complete understanding of how galaxies form and evolve over cosmic time remains a fundamental goal of astrophysics. Several key processes drive galaxy evolution, all of which require further investigation to fully constrain and understand how they combine to affect the life cycles and evolution of galaxies into the forms we observe today. With three closely related, but independent projects my PhD research provides valuable insight into understanding the processes driving star formation in the early universe through an analysis of the gas content, distribution, and the bulk motion of the gas in star forming galaxies at high redshift. In my first project we investigated for the first time the ISM properties of high-z galaxy population via the currently largest sample of 10 typical main-sequence galaxies at z∼4.5 with optical [OII] measurements from Keck /MOSFIRE spectroscopy and Subaru/MOIRCS narrow-band imaging. I find that the [OII]−SFR relation at z ∼ 4.5 cannot be described using standard local descriptions, but is consistent with a metal-dependent relation assuming metallicities around 50% solar. The analysis of this pilot sample suggests that typical log(M/M⊙) > 9 galaxies at z ∼ 4.5 to have broadly similar ISM properties as their descendants at z ∼ 2 and suggest a strong evolution of ISM properties since the Epoch of Reionization at z > 6. For my second project we provide a detailed analysis of a massive, M∗ = 1.31 ± 0.20 x1011 M⊙, star forming galaxy at z=2.47 using resoled CO(3-2) ALMA observations, MOSFIRE Hα spectroscopy, and ancillary data. We find that our galaxy although originally thought to be a starburst galaxy from the Herschel data, is a highly obscured main sequence galaxy with an AGN fraction of 0.6. In my final project we aim to place constraints on merger activity through a kinematic analysis of Hα emission of starburst galaxies at z∼1.5 observed with MOSFIRE on the Keck telescope. From these data I was able to reduce 37 masks of 9 nights of observations, which resulted in the measurement of spectroscopic redshifts for 217 galaxies both on and above the galaxy main sequence. Visual morphological analysis on an initial selection of these galaxies show that the morphology is overall regular with a mixture of disks and spheroids, with evidence of a few possible merging systems.

Publication Date


Document Type


Student Type


Degree Name

Astrophysical Sciences and Technology (Ph.D.)

Department, Program, or Center

School of Physics and Astronomy (COS)


Jeyhan Kartaltepe

Advisor/Committee Member

Julie Thomas

Advisor/Committee Member

Alexandra Pope


RIT – Main Campus