# Galaxy-scale Bars in Late-type Sloan Digital Sky Survey Galaxies Do Not Influence the Average Accretion Rates of Supermassive Black Holes

## TL;DR

This study finds that galaxy-scale bars in spiral galaxies do not significantly influence the average accretion rates of supermassive black holes over gigayear timescales, based on a large SDSS sample and X-ray stacking analysis.

## Contribution

It provides the first comprehensive statistical analysis showing that large-scale bars do not affect black hole growth in nearby spiral galaxies.

## Key findings

- Barred and unbarred galaxies have similar average black hole accretion rates.
- X-ray stacking reveals no significant difference in AGN activity between barred and unbarred galaxies.
- Large-scale bars do not influence supermassive black hole growth over gigayear timescales.

## Abstract

Galaxy-scale bars are expected to provide an effective means for driving material towards the central region in spiral galaxies, and possibly feeding supermassive black holes (BHs). Here we present a statistically-complete study of the effect of bars on average BH accretion. From a well-selected sample of 50,794 spiral galaxies (with M* ~ 0.2-30 x 10^10 Msun) extracted from the Sloan Digital Sky Survey Galaxy Zoo 2 project, we separate those sources considered to contain galaxy-scale bars from those that do not. Using archival data taken by the Chandra X-ray Observatory, we identify X-ray luminous (L_X >~ 10^41 erg/s) active galactic nuclei (AGN) and perform an X-ray stacking analysis on the remaining X-ray undetected sources. Through X-ray stacking, we derive a time-averaged look at accretion for galaxies at fixed stellar mass and star formation rate, finding that the average nuclear accretion rates of galaxies with bar structures are fully consistent with those lacking bars (Mdot_acc ~ 3 x 10^-5 Msun/yr). Hence, we robustly conclude that large-scale bars have little or no effect on the average growth of BHs in nearby (z < 0.15) galaxies over gigayear timescales.