The bar rotation rate as a diagnostic of dark matter content in the centre of disc galaxies

Buttitta, Chiara; Corsini, E. M.; Aguerri, J. A. L.; Coccato, L.; Costantin, Luca; Cuomo, V.; Debattista, Victor P.; Morelli, L.; Pizzella, A.

doi:10.1093/mnras/stad646

Cited by 7 publications

(3 citation statements)

References 84 publications

(137 reference statements)

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“…Furthermore, Algorry et al (2017), Roshan et al (2021), and others have noted that bars in these simulations generally have too low a pattern speed, in the sense that the corotation radius is much larger than the bar semimajor axis, which differs from the properties of observed bars in the nearby universe (Aguerri et al 2015; see also Buttitta et al 2023). Once again, Frankel et al (2022) find the discrepancies of bar properties between simulations and observations are lessened, but not as yet eliminated, as the resolution of the simulations is improved.…”

Section: Cosmological Simulationsmentioning

confidence: 85%

The Stability of Some Galaxy Disks is Still Perplexing

Sellwood,

Carlberg

2023

ApJ

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The problem of how some disk galaxies avoid forming bars remains unsolved. Many galaxy models having reasonable properties continue to manifest vigorous instabilities that rapidly form strong bars and no widely accepted idea has yet been advanced to account for how some disk galaxies manage to avoid this instability. It is encouraging that not all galaxies formed in recent cosmological simulations possess bars, but the dynamical explanation for this result is unclear. The unstable mode that creates a bar is understood as a standing wave in a cavity that reflects off the disk center and the corotation radius, with amplification at corotation. Here we use simulations to address one further idea that may inhibit the feedback loop and therefore contribute to stability, which is to make the disk center dynamically hot and/or to taper away mass from the inner disk, which could be masked by a bulge. Unfortunately, we find that neither strategy makes much difference to the global stability of the disk in the models we have tried. While deep density cutouts do indeed prevent feedback through the center, they still reflect incoming waves and thereby provoke a slightly different instability that again leads to a strong bar.

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Section: Cosmological Simulationsmentioning

confidence: 85%

The Stability of Some Galaxy Disks is Still Perplexing

Sellwood,

Carlberg

2023

ApJ

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“…On the other hand, NGC 4264 has a fast bar with  1 (Cuomo et al 2019). The difference has been explained by differences in the dark matter content of the galaxies (Buttitta et al 2023). We offer another explanation based on the timing of when gas was stripped from these galaxies.…”

Section: Observationsmentioning

confidence: 88%

Stellar Bars in Isolated Gas-rich Spiral Galaxies Do Not Slow Down

Beane

Hernquist

D’Onghia

et al. 2023

ApJ

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Elongated bar-like features are ubiquitous in galaxies, occurring at the centers of approximately two-thirds of spiral disks in the nearby Universe. Due to gravitational interactions between the bar and the other components of galaxies, it is expected that angular momentum and matter will redistribute over long (Gyr) timescales in barred galaxies. Previous work ignoring the gas phase of galaxies has conclusively demonstrated that bars should slow their rotation over time due to their interaction with dark matter halos. We have performed a simulation of a Milky Way–like galactic disk hosting a strong bar, including a state-of-the-art model of the interstellar medium and a live dark matter halo. In this simulation, the bar pattern does not slow down over time, and instead it remains at a stable, constant rate of rotation. This behavior has been observed in previous simulations using more simplified models for the interstellar gas, but the apparent lack of secular evolution has remained unexplained. We find that the presence of the gas phase arrests the process by which the dark matter halo slows down a bar, a phenomenon we term bar locking. This locking is responsible for stabilizing the bar pattern speed. We find that, in a Milky Way–like disk, a gas fraction of only about 5% is necessary for this mechanism to operate. Our result naturally explains why nearly all observed bars rotate rapidly and is especially relevant for our understanding of how the Milky Way arrived at its present state.

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“…Furthermore, the bar pattern speed is thought to reflect certain properties of the halo density at low radius because bars and haloes of stars and/or dark matter are believed to continuously interact during galaxy evolution through dynamical friction. Numerical models and observations suggest that the bar speed is slower when the inner halo is denser (Debattista & Sellwood 2000;Buttitta et al 2023). The pattern speed of simulated bars is also seen to slow down with the secular evolution, in contrast to its growing length and strength (Sellwood 2014).…”

Section: Introductionmentioning

confidence: 88%

The bar pattern speed of the Large Magellanic Cloud

Jiménez-Arranz,

Chemin,

Romero-Gómez

et al. 2024

A&A

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The internal kinematics of the Large Magellanic Cloud (LMC) have been studied in unprecedented depth thanks to the excellent quality of the mission data, thus revealing the disc's non-axisymmetric structure. We seek to constrain the LMC bar pattern speed using the astrometric and spectroscopic data from the mission. We applied three methods to evaluate the bar pattern speed by measuring it via: the Tremaine-Weinberg (TW) method, the Dehnen method, and a bisymmetric velocity (BV) model. These methods provide additional information on the bar properties, such as the corotation radius as well as the bar length and strength. We tested the validity of the methods with numerical simulations. A wide range of pattern speeds are inferred by the TW method, owing to a strong dependency on the orientation of the galaxy frame and the viewing angle of the bar perturbation. The simulated bar pattern speeds (corotation radii, respectively) are well recovered by the Dehnen method (BV model). Applied to the LMC data, the Dehnen method finds a pattern speed of $ thus corresponding to a bar that barely rotates and is only slightly counter-rotating with respect to the LMC disc. The BV method gives a LMC bar corotation radius of $R_c = 4.20 0.25$ kpc, corresponding to a pattern speed of $ kmskpc. It is not possible to determine which global value best represents an LMC bar pattern speed with the TW method, due to the strong variation with the orientation of the reference frame. The non-rotating bar from the Dehnen method would be at odds with the structure and kinematics of the LMC disc. The BV method result is consistent with previous estimates and gives a bar corotation-to-length ratio of $1.8 0.1$, suggesting that the LMC is hosting a slow bar.

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The bar rotation rate as a diagnostic of dark matter content in the centre of disc galaxies

Cited by 7 publications

References 84 publications

The Stability of Some Galaxy Disks is Still Perplexing

The Stability of Some Galaxy Disks is Still Perplexing

Stellar Bars in Isolated Gas-rich Spiral Galaxies Do Not Slow Down

The bar pattern speed of the Large Magellanic Cloud

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