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Abstract
majority of the stellar mass in all galaxies was assembled during the Epoch of Peak Star Formation Rate Density (“Cosmic Noon”), from z ∼ 1 − 3. An active area of research is the study of extreme star-formation rates and how they were sustained and regulated. Recent surveys have shown that galaxies with high star-formation rates are heavily obscured by dust. Spectroscopy provides significant information about the physical conditions of star-forming gas, but dust obscuration can make it difficult to robustly interpret optical and uv observations. To peer through the dust and provide insight into these questions, I helped build the Second-Generation z (redshift) and Early Universe Spectrometer (ZEUS-2), a long-slit echelle-grating spectrometer deployed on the Atacama Pathfinder EXperiment (APEX) telescope in northern Chile. ZEUS-2 operates in the 200-, 350-, and 450-micron telluric windows at medium resolution (R ∼ 1000), making it one of the few single-dish instruments currently capable of observing far-infrared fine-structure lines from high-redshift galaxies. Along with the team at Cornell, I have performed a survey of [OIII] 88 µm line emission in z ∼ 3 star-forming galaxies. Only O-type stars can produce enough high-energy UV photons to maintain doubly-ionized oxygen in the ism, and 88 µm light is not significantly extincted by dust, making the [OIII] 88 µm line a robust tracer of high-mass stars produced in an ongoing star-formation episode. I also present first-light results from ZEUS-2’s 200 µm array on APEX.
In this dissertation, I present the results of this survey, along with significant improvements I have made to our system during my Ph.D. studies. I also present detailed ALMA and JWST follow-up observations of ZEUS-1 target and starbursting quasar SDSS J1000. SDSS j1000 is a very interesting system consisting of two interacting galaxies: one of which is an extreme starburst and quasar host, the other a typical quiescent galaxy. The quasar host is modeled using [CII] 158 µm ALMA observations and found to have a well-ordered disk-like structure, and a short dynamical time with respect to its companion, resulting in an imminent major merger which represents an important precursor to the most-massive dusty galaxies in the local Universe. Together, these projects provide important insight into the history of star formation at a critical time in the history of the Universe.
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