Influence of galaxy stellar mass and observed wavelength on disc breaks in S$^4$G, NIRS0S, and SDSS data

TL;DR

This study analyzes how galaxy stellar mass and observed wavelength influence the properties of disc breaks in galaxy surface brightness profiles, revealing correlations with galaxy mass, wavelength effects on scalelengths, and implications for galaxy evolution.

Contribution

It provides a comprehensive analysis of disc break types and their dependence on galaxy mass and wavelength, using a large sample from multiple surveys, which is novel in scope and detail.

Findings

Type I discs are more common in low-mass galaxies.

Type II and III discs are more prevalent in massive galaxies.

Wavelength significantly affects disc scalelengths, especially in Type II and III profiles.

Abstract

Breaks in the surface brightness profiles in the outer regions of galactic discs are thought to have formed by various internal and external processes, and by studying the breaks we aim to better understand what processes are responsible for the evolution of the outer discs. We use a large well-defined sample to study how common the breaks are, and whether their properties depend on galaxy stellar mass or observed wavelength. We study radial surface brightness profiles of 753 galaxies, obtained from the $3.6 \mu m$ images of the Spitzer Survey of Stellar Structure in Galaxies (S$^4$G), and the $K_s$-band data from the Near InfraRed S0-Sa galaxy Survey (NIRS0S), covering a wide range of galaxy morphologies and stellar masses. Optical SDSS or Liverpool telescope data was used for 480 of these galaxies. We find that in low-mass galaxies the single exponential discs (Type I) are most common, and that their fraction decreases with increasing galaxy stellar mass. The fraction of down-bending (Type II) discs increases with stellar mass, possibly due to more common occurrence of bar resonance structures. The up-bending (Type III) discs are also more common in massive galaxies. The observed wavelength affects the scalelength of the disc of every profile type. Especially the scalelength of the inner disc of Type II profiles increases from infrared to u-band on average by a factor of $\sim 2.2$. Consistent with the previous studies, we find that Type II outer disc scalelengths ($h_o$) in late-type and low-mass galaxies are shorter in bluer wavelengths, possibly due to stellar radial migration populating the outer discs with old stars. In Type III discs $h_o$ are larger in the u-band, hinting to the presence of young stellar population in the outer disc. While the observed wavelength affects the disc parameters, it does not significantly affect the profile type in our sample. (Abridged)