Can we constrain galaxy geometry parameters using spatially integrated SED fitting?

TL;DR

This study investigates whether spatially integrated SED fitting can effectively constrain galaxy geometry parameters, finding limited success in constraining most parameters despite detailed modeling and high-quality data.

Contribution

The paper demonstrates that spatially integrated SED fitting can constrain some galaxy geometry parameters like disk radius but struggles with others, highlighting limitations of current models.

Findings

Disk radius can be constrained from SED fitting.

Inclination angle and other geometry parameters remain unconstrained.

Increasing S/N has limited impact on constraining parameters.

Abstract

Sophisticated spectral energy distribution (SED) models describe dust attenuation and emission using geometry parameters. This treatment is natural since dust effects are driven by the underlying star-dust geometry in galaxies. An example is the Starduster SED model, which divides a galaxy into a stellar disk, a stellar bulge, and a dust disk. This work utilises the Starduster SED model to study the efficacy of inferring geometry parameters using spatially integrated SED fitting. Our method fits the SED model to mock photometry produced by combining a semi-analytic model with the same SED model. Our fitting results imply that the disk radius can be constrained, while the inclination angle, dust disk to stellar disk radius ratio, bulge radius and intrinsic bulge to total luminosity ratio are unconstrained, even though 21 filters from UV to FIR are used. We also study the impact of S/N, finding that the increase of S/N (up to 80) brings limited improvements to the results. We provide a detailed discussion to explain these findings, and point out the implications for models with more general geometry.