Multi-Component stellar disk in NGC 551
Under Review in A&A, 2024
The aim of the study is to obtain a detailed three-dimensional density distribution of the stellar disk in NGC 551 and to investigate if it consists of multiple components, i.e., thin and thick disks. Assuming the baryonic disks are in hydrostatic equilibrium, we solve the joint Poisson-Boltzmann equation to estimate the three-dimensional density distribution in the stellar disk of NGC 551. Unlike previous studies, integral field spectroscopic observation is used to estimate the stellar velocity dispersion self-consistently. A three-dimensional dynamical model of the stellar disk is then built using the density solutions of the hydrostatic equation and the observed rotation curve. Using this model, simulated surface brightness maps were produced and compared with observations to infer the existence of a multi-component stellar disk in NGC 551. Further, thick + thin and thick + bar models were created to study the observational signature. Also, the dynamical model was inclined to $90\degree$ to investigate the observational signature of multi-component disks in edge-on galaxies. By comparing the simulated stellar surface brightness map of the single disk model with the observations, we find evidence of a thin disk in NGC 551, along with the thick one. This claim is supported by further comparing the simulated stellar surface brightness maps of the thick + thin and thick + bar models with observations. This suggests that our method can be used to identify multi-component stellar disks in galaxies. Further, an investigation of the simulated edge-on surface density map reveals that the scale length and the flattening ratio value gets affected by the projection effects strengthening the claim of having a detailed 3D modeling of galaxy to study the thin and thick disks.