Emulator-Assisted Calibration of a Semi-Analytic Galaxy Formation Model for the Roman Galaxy Redshift Survey
Abstract
Mock catalogues for the Roman Galaxy Redshift Survey benefit from galaxy populations whose physical properties and emission-line observables are predicted within a single galaxy-formation framework. We present an emulator-assisted calibration of the semi-analytic model Galacticus for this purpose. Because direct posterior exploration with Galacticus is computationally prohibitive, we train Gaussian-process emulators to predict the observables entering the calibration likelihood. We calibrate the model simultaneously to stellar mass functions, the star-formation-rate function, size--mass relations, the black-hole mass--velocity-dispersion relation, the mass--metallicity relation, and H-alpha luminosity functions. Combining these observables breaks parameter degeneracies present in individual fits and can reveal tensions where different observables favour different regions of parameter space. The resulting model provides a broadly successful simultaneous description of the calibration data, including the abundance and redshift evolution of H-alpha emitters relevant to the Roman Galaxy Redshift Survey. A direct Galacticus calculation at the maximum a posteriori point gives similarly good agreement with the calibration data, providing a calibrated galaxy-formation model suitable for constructing physically consistent mock catalogues for Roman.
Related
- Clustering redshift distribution calibration of weak lensing surveys using the DESI-DR1 spectroscopic dataset
- Witnessing the Earliest Phases of Galactic Wind Formation in Superluminous Supernova Hosts: Implications for Star-formation-driven Outflows in Low- and High-redshift Galaxies
- The ALMA View of High-Redshift Galaxy Formation
- Turbulent gas-rich discs at high redshift: Chaotic orbits and rapid bulge formation at high gas fraction
- Dual Signatures of Bursty Star Formation in High-Redshift UV Luminosity Functions
BibTeX
@misc{robertson2026emulatorassisted,
title = {{Emulator-Assisted Calibration of a Semi-Analytic Galaxy Formation Model for the Roman Galaxy Redshift Survey}},
author = {Andrew Robertson and Andrew Benson},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.10680},
eprint = {2609.10680},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.10680},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Emulator-Assisted Calibration of a Semi-Analytic Galaxy Formation Model for the Roman Galaxy Redshift Survey
AU - Andrew Robertson
AU - Andrew Benson
PY - 2026
DA - 2026/09/09
PB - arXiv
DO - 10.48550/arxiv.2609.10680
UR - https://arxiv.org/abs/2609.10680
AB - Mock catalogues for the Roman Galaxy Redshift Survey benefit from galaxy populations whose physical properties and emission-line observables are predicted within a single galaxy-formation framework. We present an emulator-assisted calibration of the semi-analytic model Galacticus for this purpose. Because direct posterior exploration with Galacticus is computationally prohibitive, we train Gaussian-process emulators to predict the observables entering the calibration likelihood. We calibrate the model simultaneously to stellar mass functions, the star-formation-rate function, size--mass relations, the black-hole mass--velocity-dispersion relation, the mass--metallicity relation, and H-alpha luminosity functions. Combining these observables breaks parameter degeneracies present in individual fits and can reveal tensions where different observables favour different regions of parameter space. The resulting model provides a broadly successful simultaneous description of the calibration data, including the abundance and redshift evolution of H-alpha emitters relevant to the Roman Galaxy Redshift Survey. A direct Galacticus calculation at the maximum a posteriori point gives similarly good agreement with the calibration data, providing a calibrated galaxy-formation model suitable for constructing physically consistent mock catalogues for Roman.
ER -