Pattern Speeds of BIMA SONG Galaxies with Molecule‐dominated Interstellar Mediums Using the Tremaine‐Weinberg Method

Rand, Richard J.; Wallin, John F.

doi:10.1086/423423

Cited by 55 publications

(86 citation statements)

References 88 publications

(150 reference statements)

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“…Chemin et al (2003) have assumed that the inner ring-like feature found by Regan et al (2002) but not by us, corresponds to the location of an ultra-harmonic resonance. Rand & Wallin (2004), using the BIMA SONG data and the TremaineWeinberg method, have measured a pattern speed of the bar of Ω p = 50 +3 −8 km s −1 kpc −1 , in good agreement with our determination.…”

Section: Dynamical Interpretationsupporting

confidence: 87%

Molecular Gas in NUclei of GAlaxies (NUGA)

Casasola

Hunt

Combes

et al. 2011

A&A

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We present 12 CO(1-0) and 12 CO(2-1) maps of the interacting barred LINER/Seyfert 2 galaxy NGC 3627 obtained with the IRAM interferometer at resolutions of 2. 1 × 1. 3 and 0. 9 × 0. 6, respectively. We also present single-dish IRAM 30 m 12 CO(1-0) and 12 CO(2-1) observations used to compute short spacings and complete interferometric measurements. These observations are complemented by IRAM 30 m measurements of HCN(1-0) emission detected in the center of NGC 3627. The molecular gas emission shows a nuclear peak, an elongated bar-like structure of ∼18 (∼900 pc) diameter in both 12 CO maps and, in 12 CO(1-0), a two-arm spiral feature from r ∼ 9 (∼450 pc) to r ∼ 16 (∼800 pc). The inner ∼18 bar-like structure, with a north/south orientation (PA = 14 • ), forms two peaks at the extremes of this elongated emission region. The kinematics of the inner molecular gas shows signatures of non-circular motions associated both with the 18 bar-like structure and the spiral feature detected beyond it. The 1.6 μm H-band 2MASS image of NGC 3627 shows a stellar bar with a PA = −21 • , different from the PA (= 14 • ) of the 12 CO bar-like structure, indicating that the gas is leading the stellar bar. The far-infrared Spitzer-MIPS 70 and 160 μm images of NGC 3627 show that the dust emission is intensified at the nucleus and at the ansae at the ends of the bar, coinciding with the 12 CO peaks. The GALEX far-ultraviolet (FUV) morphology of NGC 3627 displays an inner elongated (north/south) ring delimiting a hole around the nucleus, and the 12 CO bar-like structure is contained in the hole observed in the FUV. The torques computed with the HST-NICMOS F160W image and our PdBI maps are negative down to the resolution limit of our images, ∼60 pc in 12 CO(2-1). If the bar ends at ∼3 kpc, coincident with corotation (CR), the torques are negative between the CR of the bar and the nucleus, down to the resolution limit of our observations. This scenario is compatible with a recently-formed rapidly rotating bar which has had insufficient time to slow down because of secular evolution, and thus has not yet formed an inner Lindblad resonance (ILR). The presence of molecular gas inside the CR of the primary bar, where we expect that the ILR will form, makes NGC 3627 a potential smoking gun of inner gas inflow. The gas is fueling the central region, and in a second step could fuel directly the active nucleus.

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Section: Dynamical Interpretationsupporting

confidence: 87%

Molecular Gas in NUclei of GAlaxies (NUGA)

Casasola

Hunt

Combes

et al. 2011

A&A

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“…A similar effect has been observed in other Hα or CO observations (e.g., Rand & Wallin 2004;Hernandez et al 2005;Emsellem et al 2006). As a check for consistency with the stellar tracer, X values have been derived from the R-band image.…”

Section: The Bar Pattern Speedsupporting

confidence: 68%

A slow bar in a dark matter dominated galaxy

Chemin¹,

Hernandez²

2009

A&A

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Aims. We report on an estimate of the bar pattern speed Ω p for the low surface brightness spiral galaxy UGC 628. Methods. We applied the Tremaine-Weinberg method to high resolution Hα velocity and integrated emission maps of this dark matter dominated galaxy. Observations were made at the CFHT using the optical Fabry-Perot interferometer, FaNTOmM.Results. The Tremaine-Weinberg method estimates a bar pattern speed of (11.3 ± 2.0) km s −1 kpc −1 for UGC 628, which is among the lowest values found for a spiral galaxy. The corotation radius R c of the bar and the gaseous disc is R c = 9.8 +2.9 −2.0 kpc, implying a ratio R = R c /a B of 2.0 +0.5 −0.3 , where a B is the bar radius. The ratio is well beyond the usual range of values, 1.0 ≤ R ≤ 1.4, found for fast bars of high surface brightness barred galaxies. This implies that the bar in UGC 628 is slow. Conclusions. As shown through the use of numerical simulations, fast bars survive when the inner mass distribution of galaxies is dominated by the baryons over the dark matter. Our result suggests that the presence of slow bars in galaxies is likely related to the dominance of dark matter over the mass distribution.

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“…However, there are many instances where that the results suggest otherwise. Results for NGC 3031 (W98), NGC 2915 (Bureau et al 1999), NGC 5194 (Zimmer et al 2004), NGC 1068 (Rand & Wallin 2004), NGC 4321 (Hernandez et al 2005), and NGC 6946 (Fathi et al 2007) show a decreasing trend for increasing |y|.…”

Section: The Original Solution Methods Of Tw84mentioning

confidence: 95%

The Shearing H I Spiral Pattern of NGC 1365

Speights¹,

Westpfahl²

2011

ApJ

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The Tremaine-Weinberg equations are solved for a pattern speed that is allowed to vary with radius. The solution method transforms an integral equation for the pattern speed to a least-squares problem with well-established procedures for statistical analysis. The method applied to the H i spiral pattern of the barred, grand-design galaxy NGC 1365 produces convincing evidence for a radial dependence in the pattern speed. The pattern speed behaves approximately as 1/r and is very similar to the material speed. There are no clear indications of corotation or Lindblad resonances. Tests show that the results are not selection biased, and that the method is not measuring the material speed. Other methods of solving the Tremaine-Weinberg equations for shearing patterns are found to produce results in agreement with those obtained using the current method. Previous estimates that relied on the assumptions of the density-wave interpretation of spiral structure are inconsistent with the results obtained using the current method. The results are consistent with spiral structure theories that allow for shearing patterns, and contradict fundamental assumptions in the density-wave interpretation that are often used for finding spiral arm pattern speeds. The spiral pattern is winding on a characteristic timescale of ∼500 Myr.

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Pattern Speeds of BIMA SONG Galaxies with Molecule‐dominated Interstellar Mediums Using the Tremaine‐Weinberg Method

Cited by 55 publications

References 88 publications

Molecular Gas in NUclei of GAlaxies (NUGA)

Molecular Gas in NUclei of GAlaxies (NUGA)

A slow bar in a dark matter dominated galaxy

The Shearing H I Spiral Pattern of NGC 1365

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