The dust effects on galaxy scaling relations

TL;DR

This study analyzes how dust affects galaxy scaling relations in nearby spirals, correcting for dust, inclination, and decomposition effects to reveal intrinsic galaxy properties and biases in observed data.

Contribution

It introduces a method to correct galaxy photometric parameters for dust and projection effects, providing more accurate intrinsic scaling relations for spiral galaxies.

Findings

Dust significantly biases size-luminosity relations.

Corrected relations align with previous studies, validating the correction method.

Derived dust-to-stellar mass ratios are consistent with prior research.

Abstract

Accurate galaxy scaling relations are essential for a successful model of galaxy formation and evolution as they provide direct information about the physical mechanisms of galaxy assembly over cosmic time. We present here a detailed analysis of a sample of nearby spiral galaxies taken from the KINGFISH survey. The photometric parameters of the morphological components are obtained from bulge-disk decompositions using GALFIT data analysis algorithm, with surface photometry of the sample done beforehand. Dust opacities are determined using a previously discovered correlation between the central face-on dust opacity of the disk and the stellar mass surface density. The method and the library of numerical results previously obtained are used to correct the measured photometric and structural parameteres for projection (inclination), dust and decomposition effects in order to derive their intrinsic values. Galaxy disk scaling relations are then presented, both the measured (observed) and the intrinsic (corrected) ones, in the optical regime, to show the scale of the biases introduced by the aforementioned effects. The slopes of the size-luminosity relations and the dust vs stellar mass are in agreement with values found in other works. We derive mean dust optical depth and dust/stellar mass ratios of the sample, which we find to be consistent with previous studies of nearby spiral galaxies. While our sample is rather small, it is sufficient to quantify the influence of galaxy environment (dust, in this case) when deriving scaling relations.