Radial distribution of stars, gas and dust in SINGS galaxies. I. Surface photometry and morphology

TL;DR

This study provides comprehensive multi-wavelength surface brightness profiles and morphological indicators for 75 SINGS galaxies, revealing diverse structures and wavelength-dependent morphological features.

Contribution

It offers the first extensive multi-wavelength radial profiles and non-parametric morphology metrics for the SINGS galaxy sample, highlighting wavelength-dependent morphological variations.

Findings

Galaxies show diverse morphologies with multiple components.

UV and mid-IR images reveal less concentration and more asymmetry.

Wavelength affects the measured morphological parameters.

Abstract

We present ultraviolet through far-infrared surface brightness profiles for the 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). The imagery used to measure the profiles includes GALEX UV data, optical images from KPNO, CTIO and SDSS, near-IR data from 2MASS, and mid- and far-infrared images from Spitzer. Along with the radial profiles, we also provide multi-wavelength asymptotic magnitudes and several non-parametric indicators of galaxy morphology: the concentration index (C_42), the asymmetry (A), the Gini coefficient (G) and the normalized second-order moment of the brightest 20% of the galaxy's flux (M_20). Our radial profiles show a wide range of morphologies and multiple components (bulges, exponential disks, inner and outer disk truncations, etc.) that vary not only from galaxy to galaxy but also with wavelength for a given object. In the optical and near-IR, the SINGS galaxies occupy the same regions in the C_42-A-G-M_20 parameter space as other normal galaxies in previous studies. However, they appear much less centrally concentrated, more asymmetric and with larger values of G when viewed in the UV (due to star-forming clumps scattered across the disk) and in the mid-IR (due to the emission of Polycyclic Aromatic Hydrocarbons at 8.0 microns and very hot dust at 24 microns).