A Dust‐penetrated Classification Scheme for Bars as Inferred from Their Gravitational Force Fields

Buta, Ronald J.; Block, David L.

doi:10.1086/319736

Cited by 149 publications

(186 citation statements)

References 57 publications

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“…However, a large fraction of such galaxies appear to be unbarred , and the low gas fractions imply that bars would be harder to mask with star formation and dust (Buta & Block 2001). Note that while large gas fractions are expected in the early stages of galaxy formation, when we destroyed the early bars, fresh bars formed as we modeled the continued gradual growth of galaxy disks in a physically reasonable manner.…”

Section: Discussionmentioning

confidence: 97%

Mass Distribution and Bar Formation in Growing Disk Galaxy Models

Berrier

Sellwood

2016

ApJ

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We report idealized simulations that mimic the growth of galaxy disks embedded in responsive halos and bulges. The disks manifested an almost overwhelming tendency to form strong bars that we found very difficult to prevent. We found that fresh bars formed in growing disks after we had destroyed the original, indicating that bar formation also afflicts continued galaxy evolution, and not just the early stages of disk formation. This behavior raises still more insistently the previously unsolved question of how some galaxies avoid bars. Since our simulations included only collisionless star and halo particles, our findings may apply to gas-poor galaxies only; however the conundrum persists for the substantial unbarred fraction of those galaxies. Our original objective was to study how internal dynamics rearranged the distribution of mass in the disk as a generalization of our earlier study with rigid spherical components. With difficulty, we were able to construct some models that were not strongly influenced by bars, and found that halo compression, and angular momentum exchange with the disk did not alter our earlier conclusion that spiral activity is largely responsible for creating smooth density profiles and rotation curves.

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Section: Discussionmentioning

confidence: 97%

Mass Distribution and Bar Formation in Growing Disk Galaxy Models

Berrier

Sellwood

2016

ApJ

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“…The bar strength is quantified by the torque parameter Q b , which describes the maximum amplitude of tangential forcing normalised by axisymmetric radial force (Combes & Sanders 1981;Buta & Block 2001). Q b values have been measured from the torque maps derived from the 3.6 µm S 4 G images (for a description of the method see Salo et al 2010 andSalo 2002), and will be published in a compilation of bar strengths for the S 4 G sample (S. Díaz-García et al, in prep).…”

Section: Structural Parametersmentioning

confidence: 99%

Hα kinematics of S4G spiral galaxies – II. Data description and non-circular motions

Erroz-Ferrer¹,

Knapen²,

Leaman³

et al. 2015

Monthly Notices of the Royal Astronomical Society

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We present a kinematical study of 29 spiral galaxies included in the Spitzer Survey of Stellar Structure in Galaxies, using Hα Fabry-Perot data obtained with the Galaxy Hα Fabry-Perot System instrument at the William Herschel Telescope in La Palma, complemented with images in the R band and in Hα. The primary goal is to study the evolution and properties of the main structural components of galaxies through the kinematical analysis of the FP data, complemented with studies of morphology, star formation and mass distribution. In this paper we describe how the FP data have been obtained, processed and analysed. We present the resulting moment maps, rotation curves, velocity model maps and residual maps. Images are available in FITS format through the NASA/IPAC Extragalactic Database and the Centre de Données Stellaires. With these data products we study the non-circular motions, in particular those found along the bars and spiral arms. The data indicate that the amplitude of the non-circular motions created by the bar does not correlate with the bar strength indicators. The amplitude of those non-circular motions in the spiral arms does not correlate with either arm class or star formation rate along the spiral arms. This implies that the presence and the magnitude of the streaming motions in the arms is a local phenomenon.

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“…6, where we plot the relative size of the nuclear rings, defined here as the diameter of the ring, as measured from our Hα images and tabulated in Table 1, divided by the diameter of the complete disk of its host galaxy (D 25 from the RC3), against the gravitational torque Q b due to the bar. Values of Q b have been taken mostly from Block et al (2001), who analysed the same sample as analysed in this paper, but where other measurements were available from the literature (Buta & Block 2001;Laurikainen & Salo 2002) averages were used. For NGC 1530 and NGC 6951 (a nuclear ring galaxy from Knapen et al 2002 included in Fig.…”

Section: Large Nuclear Rings Occur In Weak Barsmentioning

confidence: 99%

Structure and star formation in disk galaxies

Knapen¹

2004

A&A

103

125

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Abstract. From Hα images of a carefully selected sample of 57 relatively large, Northern spiral galaxies with low inclination, we study the distribution of the Hα emission in the circumnuclear and nuclear regions. At a resolution of around 100 parsec, we find that the nuclear Hα emission in the sample galaxies is often peaked, and significantly more often so among AGN host galaxies. The circumnuclear Hα emission, within a radius of two kpc, is often patchy in late-type, and absent or in the form of a nuclear ring in early-type galaxies. There is no clear correlation of nuclear or circumnuclear Hα morphology with the presence or absence of a bar in the host galaxy, except for the nuclear rings which occur in barred hosts. The presence or absence of close bright companion galaxies does not affect the circumnuclear Hα morphology, but their presence does correlate with a higher fraction of nuclear Hα peaks. Nuclear rings occur in at least 21% (±5%) of spiral galaxies, and occur predominantly in galaxies also hosting an AGN. Only two of our 12 nuclear rings occur in a galaxy which is neither an AGN nor a starburst host. We confirm that weaker bars host larger nuclear rings. The implications of these results on our understanding of the occurrence and morphology of massive star formation, as well as non-stellar activity, in the central regions of galaxies are discussed.

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A Dust‐penetrated Classification Scheme for Bars as Inferred from Their Gravitational Force Fields

Cited by 149 publications

References 57 publications

Mass Distribution and Bar Formation in Growing Disk Galaxy Models

Mass Distribution and Bar Formation in Growing Disk Galaxy Models

Hα kinematics of S4G spiral galaxies – II. Data description and non-circular motions

Structure and star formation in disk galaxies

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