Over the last several decades, ever-more precise studies of the large-scale distribution of matter in the Universe have led to important shifts in our understanding of fundamental physics.  Maps of the Cosmic Microwave Background (CMB) along with spectroscopic galaxy surveys form the basis of the LCDM model of cosmology, wherein the dynamics of the expanding Universe are driven by competing forces of dark matter and dark energy.  Despite the remarkable success of this model, the true nature of these forces remains a mystery.  Indeed, tensions between large-scale structure and other measurements of cosmic expansion may hint that even our current limited understanding of cosmic expansion may be faulty.

This project explores a novel survey technique known as Line Intensity Mapping (LIM) with the potential to significantly expand upon current large-scale structure observations.  Where spectroscopic surveys require directly imaging thousands of individual galaxies, LIM surveys map the unresolved emission from many galaxies at once, reducing the sensitivity and resolution requirements necessary to map large volumes at great distances.  LIM experiments at millimeter wavelengths are particularly exciting, as they can leverage the vast observational experience built up by the CMB community at these wavelengths.  This potential, to expand the reach of large-scale structure surveys using the heritage of CMB experiments, makes LIM an exciting near-future opportunity for precision cosmology.

Several demonstrator-scale LIM instruments are currently operating or under construction, but these first-generation observatories lack the sensitivity necessary to compete with modern cosmological surveys.  In this project, we will create a fast end-to-end simulation pipeline capable of creating mock LIM signals, observing them with mock instruments, and forecasting constraints on cosmic expansion and dark energy.  This will enable us to simulate different cosmologies and instrument designs, laying the groundwork for a wide range of future LIM experiments.

Key Objectives:

1. Create a code for simulating wide-area LIM maps containing the large-scale structure signal as well as astrophysical foregrounds.
2. Model instrument noise and systematics for a simulated observation of these maps.
3. Create an analysis pipeline to produce cosmological parameter forecasts based on simulated data and instruments.