Spiral structure in nearby galaxies - I. Sample, data analysis and overview of results

Kendall, Simon; Kennicutt, Robert C.; Clarke, C. J.

doi:10.1111/j.1365-2966.2011.18422.x

Cited by 85 publications

(99 citation statements)

References 64 publications

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“…The spiral arms of M100 are isolated from the underlying stellar disc with separate estimates from 3.6 µm, 4.5 µm and optical colour by Kendall et al (2011). The azimuthal offset of the spiral arm ridge line between the wavelengths is ∼ 0-5 ′′ along the arms.…”

Section: Gma Classification Based On Galacticmentioning

confidence: 99%

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Variation in GMC Association Properties across the Bars, Spiral Arms, Inter-arms, and Circumnuclear Region of M100 (NGC 4321) Extracted from ALMA Observations

Pan

Kuno

2017

ApJ

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We study the physical properties of giant molecular cloud associations (GMAs) in M100 (NGC 4321) using the ALMA Science Verification feathered (12-m+ACA) data in 12 CO (1-0). To examine the environmental dependence of GMA properties, GMAs are classified based on their locations in the various environments as circumnuclear ring (CNR), bar, spiral, and inter-arm GMAs. The CNR GMAs are massive and compact, while the inter-arm GMAs are diffuse with low surface density. GMA mass and size are strongly correlated, as suggested by Larson (1981). However, the diverse power-law index of the relation implies that the GMA properties are not uniform among the environments. The CNR and bar GMAs show higher velocity dispersion than those in other environments. We find little evidence for a correlation between GMA velocity dispersion and size, which indicates that the GMAs are in diverse dynamical states. Indeed, the virial parameter of GMAs spans nearly two orders of magnitude. Only the spiral GMAs are in general self-gravitating. Star formation activity of the GMAs decreases in order over the CNR, spiral, bar, and the inter-arm GMAs. The diverse GMA and star formation properties in different environments lead to variations in the Kennicutt-Schmidt relation. A combination of multiple mechanisms or gas phase change is necessary to explain the observed slopes. Comparisons of GMA properties acquired with the use of the 12-m-array observations with those from the feathered data are also presented. The results show that the missing flux and extended emission cannot be neglected for the study of environmental dependence.

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Section: Gma Classification Based On Galacticmentioning

confidence: 99%

“…The HII regions identified by Knapen (1998) distributions. This may be due to the influence of one or both companion galaxies (Kendall et al 2011). GMAs in the spiral pattern are classified as spiral GMAs.…”

Section: Gma Classification Based On Galacticmentioning

confidence: 99%

Variation in GMC Association Properties across the Bars, Spiral Arms, Inter-arms, and Circumnuclear Region of M100 (NGC 4321) Extracted from ALMA Observations

Pan

Kuno

2017

ApJ

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“…The spiral arms of NGC 7771, as well as outer arms of NGC 7769 have tidal origin (e.g. Toomre & Toomre 1972;Kormendy & Norman 1979;Kendall et al 2011). The existence of bar is a characteristic feature of most grand-design galaxies (e.g.…”

Section: Description Of the Systemmentioning

confidence: 99%

Hα Velocity Fields and Galaxy Interaction in the Quartet of Galaxies NGC 7769, 7770, 7771 and 7771A

2016

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Abstract. The quartet of galaxies NGC 7769, 7770, 7771 and 7771A is a system of interacting galaxies. Close interaction between galaxies caused characteristic morphological features: tidal arms and bars, as well as an induced star formation. In this study, we performed the Fabry-Perot scanning interferometry of the system in Hα line and studied the velocity fields of the galaxies. We found that the rotation curve of NGC 7769 is weakly distorted. The rotation curve of NGC 7771 is strongly distorted with the tidal arms caused by direct flyby of NGC 7769 and flyby of a smaller neighbor NGC 7770. The rotation curve of NGC 7770 is significantly skewed because of the interaction with the much massive NGC 7771. The rotation curves and morphological disturbances suggest that the NGC 7769 and NGC 7771 have passed the first pericenter stage, however, probably the second encounter has not happened yet. Profiles of surface brightness of NGC 7769 have a characteristic break, and profiles of color indices have a minimum at a radius of intensive star formation induced by the interaction with NGC 7771.

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“…(14), the density contrast increases with radius. Kendall et al (2011) and Elmegreen et al (2011) showed many galaxies with a growth of density contrast with radius. If we adopt ε d = ε s , the density contrast varies as the square of the radius, which seems a little too fast in many cases.…”

Section: Relation Between Density Contrast and Perturbation Amplitudementioning

confidence: 99%

A new model for gravitational potential perturbations in disks of spiral galaxies. An application to our Galaxy

Junqueira

Lépine

Braga

et al. 2013

A&A

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Aims. We propose a new, more realistic description of the perturbed gravitational potential of spiral galaxies, with spiral arms having Gaussian-shaped groove profiles. The aim is to reach a self-consistent description of the spiral structure, that is, one in which an initial potential perturbation generates, by means of the stellar orbits, spiral arms with a profile similar to that of the imposed perturbation. Self-consistency is a condition for having long-lived structures. Methods. Using the new perturbed potential, we investigate the stable stellar orbits in galactic disks for galaxies with no bar or with only a weak bar. The model is applied to our Galaxy by making use of the axisymmetric component of the potential computed from the Galactic rotation curve, in addition to other input parameters similar to those of our Galaxy. The influence of the bulge mass on the stellar orbits in the inner regions of a disk is also investigated. Results. The new description offers the advantage of easy control of the parameters of the Gaussian profile of its potential. We compute the density contrast between arm and inter-arm regions. We find a range of values for the perturbation amplitude from 400 to 800 km 2 s −2 kpc −1 , which implies an approximate maximum ratio of the tangential force to the axisymmetric force between 3% and 6%. Good self-consistency of arm shapes is obtained between the Inner Lindblad resonance (ILR) and the 4:1 resonance. Near the 4:1 resonance the response density starts to deviate from the imposed logarithmic spiral form. This creates bifurcations that appear as short arms. Therefore the deviation from a perfect logarithmic spiral in galaxies can be understood as a natural effect of the 4:1 resonance. Beyond the 4:1 resonance we find closed orbits that have similarities with the arms observed in our Galaxy. In regions near the center, elongated stellar orbits appear naturally, in the presence of a massive bulge, without imposing any bar-shaped potential, but only extending the spiral perturbation a little inward of the ILR. This suggests that a bar is formed with a half-size ∼3 kpc by a mechanism similar to that of the spiral arms. Conclusions. The potential energy perturbation that we adopted represents an important step in the direction of self-consistency, compared to previous sine function descriptions of the potential. In addition, our model produces a realistic description of the spiral structure, which is able to explain several details that were not yet understood.

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Spiral structure in nearby galaxies - I. Sample, data analysis and overview of results

Cited by 85 publications

References 64 publications

Variation in GMC Association Properties across the Bars, Spiral Arms, Inter-arms, and Circumnuclear Region of M100 (NGC 4321) Extracted from ALMA Observations

Variation in GMC Association Properties across the Bars, Spiral Arms, Inter-arms, and Circumnuclear Region of M100 (NGC 4321) Extracted from ALMA Observations

Hα Velocity Fields and Galaxy Interaction in the Quartet of Galaxies NGC 7769, 7770, 7771 and 7771A

A new model for gravitational potential perturbations in disks of spiral galaxies. An application to our Galaxy

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