LIMFAST. II. Line Intensity Mapping as a Probe of High-Redshift Galaxy Formation

• Main Authors: Sun, Guochao, Mas-Ribas, Lluís, Chang, Tzu-Ching, Furlanetto, Steven R, Mebane, Richard H, Gonzalez, Michael O, Parsons, Jasmine, Trapp, A. C
• Format: Journal Article
• Language: English
• Published: 23-03-2023
• Subjects: Physics - Astrophysics of Galaxies; Physics - Cosmology and Nongalactic Astrophysics; Physics - Instrumentation and Methods for Astrophysics
• DOI: 10.48550/arxiv.2206.14186

The epoch of reionization (EoR) offers a unique window into the dawn of
galaxy formation, through which high-redshift galaxies can be studied by
observations of both themselves and their impact on the intergalactic medium.
Line intensity mapping (LIM) promises to explore cosmic reionization and its
driving sources by measuring intensity fluctuations of emission lines tracing
the cosmic gas in varying phases. Using LIMFAST, a novel semi-numerical tool
designed to self-consistently simulate LIM signals of multiple EoR probes, we
investigate how building blocks of galaxy formation and evolution theory, such
as feedback-regulated star formation and chemical enrichment, might be studied
with multi-tracer LIM during the EoR. On galaxy scales, we show that the star
formation law and the feedback associated with star formation can be indicated
by both the shape and redshift evolution of LIM power spectra. For a baseline
model of metal production that traces star formation, we find that lines highly
sensitive to metallicity are generally better probes of galaxy formation
models. On larger scales, we demonstrate that inferring ionized bubble sizes
from cross-correlations between tracers of ionized and neutral gas requires a
detailed understanding of the astrophysics that shape the line luminosity--halo
mass relation. Despite various modeling and observational challenges,
wide-area, multi-tracer LIM surveys will provide important high-redshift tests
for the fundamentals of galaxy formation theory, especially the interplay
between star formation and feedback by accessing statistically the entire
low-mass population of galaxies as ideal laboratories, complementary to
upcoming surveys of individual sources by new-generation telescopes.