Abstract: Line intensity mapping is a growing technique for obtaining tomographic maps of the universe. Line intensity maps feature the integrated emission of a target spectral line from all galaxies within the field of view, making it an unbiased tracer of galaxy emission and a strong tool for galaxy evolution studies. Furthermore, line intensity mapping surveys may probe unprecedented volumes of the universe with modest time requirements, allowing for leading sensitivities of cosmological parameters.
In this thesis, I describe modeling efforts for measurements of the intensity mapping signal and for instrumentation developed for the Experiment for Cryogenic Large- aperture Intensity Mapping (EXCLAIM!). EXCLAIM is a pathfinding balloon-borne intensity mapping instrument aiming to map ionized carbon ([CII]) and carbon monoxide (CO) at redshifts 2.5 < z < 3.5 and z < 0.64, respectively. I characterize the target observables in the survey and describe methods for forecasting the performance of the instrument. I apply these forecasting tools to the EXCLAIM survey and to a hypothetical space-based survey, which may be free from the limitations of cosmic variance.
The EXCLAIM detectors and optical systems are also described in detail, and with a dual focus on system-level requirements. EXCLAIM features nascent superconducting spectrometer and detector technologies, which must be carefully characterized and modeled before the flight. I describe an operational procedure that may be used to optimize the detectors for an evolving signal, providing a critical advantage for EXCLAIM’s detectors over competing technologies. Finally, the optical system is modeled and shown to comply with system-level mission goals.