Bar-driven Gas Dynamics in NGC 1097: Insights from Hydrodynamical Simulations and CO(2–1) Observations

Abstract To address the disk-halo degeneracy problem, we investigate the nearby barred spiral galaxy NGC 1097. We construct mass models using 3.6 and 4.5 μ m near-infrared photometric images from the S 4 G survey, constrained by rotation curves derived from CO( J = 2–1) data from the PHANGS-ALMA survey. These models serve as inputs for a suite of hydrodynamic simulations, where we systematically test the influence of key parameters including the disk mass scaling factor ( f M ), bar pattern speed (Ω b ), and gas sound speed ( c s ). By comparing the CO(2–1) kinematic maps in the bar region with those from the simulations, we perform a standard χ 2 analysis to identify the best-fit model. The best-fit model reproduces the observed morphological and kinematic gas features of the galaxy, indicating that NGC 1097 likely hosts a maximal disk with a slowly rotating bar. We also test the influence of a boxy/peanut-shaped (B/P) bulge by incorporating a double-peaked vertical density profile into the model. This B/P structure tends to weaken the bar’s non-axisymmetric potential and necessitate a higher bar pattern speed to reproduce the observed gas morphology.