← SLICK overview · All research
Predicting the Line-Emitting Universe
Line-intensity mapping measures the combined emission from galaxies and diffuse sources across large cosmic volumes—even when individual galaxies are too faint to detect.
Rather than resolving one galaxy at a time, line-intensity mapping (LIM) uses fluctuations in spectral-line brightness to probe how matter and emitting gas are distributed in three dimensions. Different lines, including CO and [C II], provide complementary windows into star formation and the interstellar medium.
Why LIM Matters
LIM offers access to large volumes and faint source populations that are difficult to characterize with conventional galaxy surveys. Measurements of mean line intensity, clustering, and cross-correlations with galaxy catalogs can help connect the cosmic distribution of matter to the evolution of emitting gas.
Projects such as COMAP, TIME, TIM, and FYST/Prime-Cam illustrate the range of observational approaches and target lines in this growing field. Their observing strategies, status, and science goals differ; the links below lead to project information.
The Astrophysical Modeling Challenge
Interpreting an intensity map requires more than knowing the underlying dark-matter distribution. The measured signal also depends on which galaxies emit, how bright they are in a given line, the scatter in luminosity at fixed galaxy properties, and how emission varies across environments and cosmic time.
Simple empirical relations are useful starting points, but they can hide the dependence of emission on gas conditions and feedback. This is especially limiting when comparing several lines or trying to infer astrophysics from a measured power spectrum.
What SLICK Contributes
Physics-informed line luminosities
SLICK computes line emission from modeled gas conditions, creating a route to investigate why a luminosity relation or line ratio changes rather than assuming a fixed galaxy-wide prescription.
Multi-tracer predictions
The SLICK-2 extensions aim to model multiple molecular, neutral, and ionized tracers consistently, enabling studies of complementary lines and their potential cross-correlations.
From galaxies to intensity statistics
Applying SLICK to simulated galaxy populations provides a path toward constructing line-intensity maps, luminosity functions, and clustering predictions, including power spectra and cross-correlations.
More informative inference
In future analyses, varying the underlying gas and galaxy-formation physics could help quantify modeling uncertainty and identify which combinations of lines are most informative about astrophysical processes.
Current Direction
My ongoing SLICK-LIM research focuses on connecting emission predictions to cosmological observables and examining how assumptions about galaxy formation and the ISM affect LIM forecasts. These are research goals and ongoing developments, not claims that every analysis described here has already been completed.
Selected Related Work
- Bracks et al., including Garcia, K. (2026), Forecasting the Cross Correlation of Terahertz Intensity Mapper [C II] Line Intensity Maps with Euclid Galaxies, ApJ.
- Agrawal et al., including Garcia, K. (2026), A New Window into the Baryon Cycle at Cosmic Noon with Line Intensity Mapping, preprint.
- Karoumpis et al., including Garcia, K. (2024), [CII] line intensity mapping the epoch of reionization with Prime-Cam on FYST: II. CO foreground masking, A&A.