Global Photometric Properties of Barred Galaxies

Ohta, Kouji

doi:10.1017/s0252921100049393

Cited by 5 publications

(1 citation statement)

References 15 publications

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“…These results are broadly consistent with observations that show a variety of radial Fourier profiles of bars, ranging from simple symmetric profiles, that can be represented by two overlapping Gaussian components, to more complex curves. Since Cn/C0 value spans between 0.4 and 0.8 (Elmegreen & Elmegreen 1985;Ohta et al 1990;Ohta 1996;Aguerri et al 1998Aguerri et al , 2003Buta et al 2006), both GA galaxies would be classified as barred. Moreover, the amplitudes of GA2 show relatively high values also at large radii, where the signature of streaming motions (Figure 6) is already lost but prominent spiral arms are present.…”

Section: Quantification Of Bar Strength and Lengthmentioning

confidence: 99%

Properties of barred spiral discs in hydrodynamical cosmological simulations

Goz¹,

Monaco

Murante

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We present a quantification of the properties of bars in two N-body+SPH cosmological simulations of spiral galaxies, named GA and AqC. The initial conditions were obtained using the zoom-in technique and represent two dark matter (DM) halos of 2−3×10 12 M ⊙ , available at two different resolutions. The resulting galaxies are presented in the companion paper of Murante et al. (2014). We find that the GA galaxy has a bar of length 8.8 kpc, present at the two resolution levels even though with a slightly different strength. Classical bar signatures (e.g. pattern of streaming motions, high m = 2 Fourier mode with roughly constant phase) are consistently found at both resolutions. Though a close encounter with a merging satellite at z ∼ 0.6 (mass ratio 1 : 50) causes a strong, transient spiral pattern and some heating of the disk, we find that bar instability is due to secular process, caused by a low Toomre parameter Q 1 due to accumulation of mass in the disk. The AqC galaxy has a slightly different history: it suffers a similar tidal disturbance due to a merging satellite at z ∼ 0.5 but with a mass ratio of 1 : 32, that triggers a bar in the high-resolution simulation, while at low resolution the merging is found to take place at a later time, so that both secular evolution and merging are plausible triggers for bar instability.

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Section: Quantification Of Bar Strength and Lengthmentioning

confidence: 99%

Properties of barred spiral discs in hydrodynamical cosmological simulations

Goz¹,

Monaco

Murante

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Angular Momentum Redistribution and the Evolution and Morphology of Bars

Athanassoula¹

2003

Galaxies and Chaos

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Angular momentum exchange is a driving process for the evolution of barred galaxies. Material at resonance in the bar region loses angular momentum which is taken by material at resonance in the outer disc and/or the halo. By losing angular momentum, the bar grows stronger and slows down. This evolution scenario is backed by both analytical calculations and by N -body simulations. The morphology of the bar also depends on the amount of angular momentum exchanged.

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Characterization of galactic bars from 3.6μm S⁴G imaging

Díaz-García

Salo

Laurikainen

et al. 2016

A&A

140

182

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Context. Stellar bars play an essential role in the secular evolution of disk galaxies because they are responsible for the redistribution of matter and angular momentum. Dynamical models predict that bars become stronger and longer in time, while their rotation speed slows down. Aims. We use the Spitzer Survey of Stellar Structure in Galaxies (S 4 G) 3.6 µm imaging to study the properties (length and strength) and fraction of bars at z = 0 over a wide range of galaxy masses (M * ≈ 10 8 −10 11 M ) and Hubble types (−3 ≤ T ≤ 10). Methods. We calculated gravitational forces from the 3.6 µm images for galaxies with a disk inclination lower than 65• . We used the maximum of the tangential-to-radial force ratio in the bar region (Q b ) as a measure of the bar-induced perturbation strength for a sample of ∼600 barred galaxies. We also used the maximum of the normalized m = 2 Fourier density amplitude (A max 2 ) and the bar isophotal ellipticity (ε) to characterize the bar. Bar sizes were estimated i) visually; ii) from ellipse fitting; iii) from the radii of the strongest torque; and iv) from the radii of the largest m = 2 Fourier amplitude in the bar region. By combining our force calculations with the H  kinematics from the literature, we estimated the ratio of the halo-to-stellar mass (M h /M * ) within the optical disk and by further using the universal rotation curve models, we obtained a first-order model of the rotation curve decomposition of 1128 disk galaxies. Results. We probe possible sources of uncertainty in our Q b measurements: the assumed scale height and its radial variation, the influence of the spiral arms torques, the effect of non-stellar emission in the bar region, and the dilution of the bar forces by the dark matter halo (our models imply that only ∼10% of the disks in our sample are maximal). We find that for early-and intermediate-type disks (−3 ≤ T < 5), the relatively modest influence of the dark matter halo leads to a systematic reduction of the mean Q b by about 10−15%, which is of the same order as the uncertainty associated with estimating the vertical scale height. The halo correction on Q b becomes important for later types, implying a reduction of ∼20−25% for T = 7−10. Whether the halo correction is included or not, the mean Q b shows an increasing trend with T . However, the mean A max 2 decreases for lower mass late-type systems. These opposing trends are most likely related to the reduced force dilution by bulges when moving towards later type galaxies. Nevertheless, when treated separately, both the early-and late-type disk galaxies show a strong positive correlation between Q b and A max 2 . For spirals the mean ε ≈ 0.5 is nearly independent of T , but it drops among S0s (≈0.2). The Q b and ε show a relatively tight dependence, with only a slight difference between early and late disks. For spirals, all our bar strength indicators correlate with the bar length (scaled to isophotal size). Late-type bars are longer than previously found in the literature. The bar fraction...

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Global Photometric Properties of Barred Galaxies

Abstract: Abstract. Global photometric properties of barred galaxies are reviewed based on the surface photometry of barred galaxies.

Cited by 5 publications

References 15 publications

Properties of barred spiral discs in hydrodynamical cosmological simulations

Properties of barred spiral discs in hydrodynamical cosmological simulations

Angular Momentum Redistribution and the Evolution and Morphology of Bars

Characterization of galactic bars from 3.6μm S⁴G imaging

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Global Photometric Properties of Barred Galaxies

Abstract: Abstract. Global photometric properties of barred galaxies are reviewed based on the surface photometry of barred galaxies.

Cited by 5 publications

References 15 publications

Properties of barred spiral discs in hydrodynamical cosmological simulations

Properties of barred spiral discs in hydrodynamical cosmological simulations

Angular Momentum Redistribution and the Evolution and Morphology of Bars

Characterization of galactic bars from 3.6μm S4G imaging

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Product

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Characterization of galactic bars from 3.6μm S⁴G imaging