# A Self-consistent Framework for Multiline Modeling in Line Intensity Mapping Experiments

## TL;DR

This paper introduces a physically-motivated, self-consistent modeling framework for line intensity mapping that connects galaxy infrared luminosity to dark matter halos, enabling better interpretation of LIM data across multiple lines.

## Contribution

It develops a new modeling framework for LIM that incorporates analytic galaxy-halo connections and applies it to multiple emission lines, improving physical inference from LIM observations.

## Key findings

- Models consistent with current observational constraints.
- Demonstrates extraction of ISM properties from auto and cross-correlation analyses.
- Shows potential for studying ISM evolution over cosmic time.

## Abstract

Line intensity mapping (LIM) is a promising approach to study star formation and the interstellar medium (ISM) in galaxies by measuring the aggregate line emission from the entire galaxy population. In this work, we develop a simple yet physically-motivated framework for modeling the line emission as would be observed in LIM experiments, which is done by building on analytic models of the Cosmic Infrared Background that connect total infrared luminosity of galaxies to their host dark matter halos. We present models of the HI 21cm, CO(1-0), [C II] 158$\mu$m, and [N II] 122 and 205$\mu$m lines consistent with current observational constraints. With four case studies of various combinations of these lines that probe different ISM phases, we demonstrate the potential for reliably extracting physical properties of the ISM, and the evolution of these properties with cosmic time, from auto and cross-correlation analysis of these lines as measured by future LIM experiments.