Bridging Astrophysics and Cosmology with Line Intensity Mapping

Zoom Recording Passcode: C47v#^5r

Line intensity mapping is a new, rapidly evolving observational and analysis technique for obtaining statistical information about the large-scale spatial and redshift distribution of astrophysical processes associated with the emission or absorption of a particular line, but which does not require producing high-resolution images.  It promises to be particularly powerful when used with lines that trace star formation and the evolution of galaxies, but for which instrumentation with the requisite sensitivity or angular resolution to detect individual galaxies is lacking, or the emission is intrinsically extended. 

I focus on two examples, the Hydrogen Epoch of Reionization Array (HERA) and the Terahertz Intensity Mapper (TIM), which use the lines of neutral hydrogen (21 cm at 27 > z > 6) and ionized carbon (158 micron at 1.5 > z > 0.5), respectively.  HERA, a low frequency radio interferometer operating in South Africa, investigates the conditions in the intergalactic medium during cosmic dawn (the birth of the first stars and stellar-mass black holes) by tracing the heating and ionization of hydrogen.  TIM is a balloon-borne far-infrared spectrometer to probe galaxies during "cosmic noon" (the peak of cosmic star formation).  In particular, I discuss how HERA's current and upcoming measurements can be used to constrain the optical depth to reionization, a major "nuisance parameter" for next-generation CMB measurements looking to constrain the sum of the neutrino masses, and how TIM’s may be used to add new insight to the cosmic star formation history.

I include recent results and progress from HERA, and new forecasts and constraints from archival data relevant to TIM, which is set to fly from Antarctica in late 2026.