The clustering of barred galaxies in the local Universe

TL;DR

This study investigates the clustering of barred galaxies in the local Universe using SDSS data, finding no significant difference in clustering between barred and unbarred galaxies across various parameters.

Contribution

It provides the first comprehensive analysis showing that barred galaxies do not cluster differently from unbarred ones, challenging merger-based formation theories.

Findings

Clustering of barred and unbarred galaxies is similar across scales.

No correlation between bar properties and clustering.

Possible stronger clustering of elliptical bars at large scales.

Abstract

We study the clustering properties of barred galaxies using data from the Sloan Digital Sky Survey (SDSS). We compute projected redshift-space two-point cross-correlation functions w_p(r_p) for a sample of nearly 1000 galaxies for which we have performed detailed structural decompositions using the methods described in Gadotti (2009). The sample includes 286 barred galaxies. The clustering of barred and unbarred galaxies of similar stellar mass is indistinguishable over all the scales probed (~20kpc - 30Mpc). This result also holds even if the sample is restricted to bars with bluer g-i colours (and hence younger ages). Our result also does not change if we split our sample of barred galaxies according to bar-to-total luminosity ratio, bar boxyness, effective surface brightness, length, or the shape of the surface density profile within the bar. There is a hint that red, elliptical bars are more strongly clustered than red and less elliptical bars, on scales >~ 1 Mpc, although the statistical significance is not high. We conclude that there is no significant evidence that bars are a product of mergers or interactions. We tentatively interpret the stronger clustering of the more elliptical bars as evidence that they are located in older galaxies, which reside in more massive haloes.