Bars in low-density environments rotate faster than bars in dense regions

Abstract

Does the environment of a galaxy directly influence the kinematics of its bar? We present observational evidence that bars in high-density environments exhibit significantly slower rotation rates than bars in low-density environments. Galactic bars are central, extended structures composed of stars, dust and gas, present in approximately 30 to 70 per cent of luminous spiral galaxies in the local Universe. Recent simulation studies have suggested that the environment can influence the bar rotation rate, $R$, which is used to classify bars as either fast ($1\le R\le 1.4$) or slow ($R>1.4$). We use estimates of $R$ obtained with the Tremaine-Weinberg method applied to Integral Field Unit spectroscopy from MaNGA and CALIFA. After cross-matching these with the projected neighbour density, $\log \Sigma$, we retain 286 galaxies. The analysis reveals that bars in high-density environments are significantly slower (median $R=1.65_{-0.11}^{+0.13}$) compared to bars in low-density environments (median $R=1.39_{-0.08}^{+0.09}$); Anderson-Darling $\text{p}$-value of $p_{\mathrm{AD}}=0.002$ ($3.1\sigma$). This study marks the first empirical test of the hypothesis that fast bars are formed by global instabilities in isolated galaxies, while slow bars are triggered by tidal interactions in dense environments, in agreement with predictions from numerous $\text{N}$-body simulations. Future studies would benefit from a larger sample of galaxies with reliable Integral Field Unit data, required to measure bar rotation rates. Specifically, more data are necessary to study the environmental influence on bar formation within dense settings (i.e. groups, clusters and filaments).

8 pages, 2 figures, accepted for publication in MNRAS

References in corpus (24)

• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• Galaxy Zoo: the dependence of morphology and colour on environment
• Updated Nearby Galaxy Catalog
• Dynamical modelling of the Galactic bulge and bar: the Milky Way's bar pattern speed, stellar, and dark matter mass distribution
• The Dependence of Bar Frequency on Galaxy Mass, Colour, and Gas Content -- and Angular Resolution -- in the Local Universe
• Galaxy Zoo: Secular evolution of barred galaxies from structural decomposition of multi-band images
• Model-based pattern speed estimates for 38 barred galaxies
• The environmental dependence of the chemical properties of star-forming galaxies
• A Milky Way-like barred spiral galaxy at a redshift of 3
• Bar Formation from Galaxy Flybys
• A numerical study of interactions and stellar bars
• The rapid onset of stellar bars in the baryon-dominated centers of disk galaxies
• The Bar and Spiral Arms in the Milky Way: Structure and Kinematics
• Galaxy Zoo: Stronger bars facilitate quenching in star forming galaxies
• Kinematic clues to bar evolution for galaxies in the local universe: why the fastest rotating bars are rotating most slowly
• Galaxy Zoo: Kinematics of strongly and weakly barred galaxies
• SDSS-IV MaNGA: Bar pattern speed estimates with the Tremaine-Weinberg method and their error sources
• Barred spiral galaxies in modified gravity theories
• Bars formed in galaxy merging and their classification with deep learning
• SDSS IV MaNGA: Bar pattern speed in Milky Way Analogue galaxies
• The Effect of Dark Matter Halo Shape on Bar Buckling and Boxy/Peanut Bulges
• Exploring the High-Mass End of the Stellar Mass Function of Star Forming Galaxies at Cosmic Noon
• Structures induced by companions in galactic discs
• Galaxy mass-size segregation in the cosmic web from the CAVITY parent sample