scholarly journals Barred spiral galaxies

1970 ◽  
Vol 38 ◽  
pp. 351-355
Author(s):  
K. C. Freeman
Keyword(s):  
Spiral Galaxies ◽  
Spiral Structure ◽  
Theoretical Work ◽  
Barred Spiral Galaxies

We point out some properties of barred spiral galaxies which are important for the theory of their formation and spiral structure, and describe some theoretical work on the dynamics of these systems.

scholarly journals Outer spiral structure in disk galaxies

2016 ◽  
Vol 11 (S321) ◽  
pp. 123-123
Author(s):  
P.A. Patsis
Keyword(s):  
Periodic Orbits ◽  
Spiral Galaxies ◽  
Spiral Structure ◽  
Disk Galaxies ◽  
Spiral Arms ◽  
Chaotic Orbits ◽  
Grand Design ◽  
Pattern Speed ◽  
Spiral Structures ◽  
Barred Spiral Galaxies

AbstractIn several grand design barred-spiral galaxies it is observed a second, fainter, outer set of spiral arms. Typical examples of objects of this morphology can be considered NGC 1566 and NGC 5248. I suggest that such an overall structure can be the result of two dynamical mechanisms acting in the disc. The bar and both spiral systems rotate with the same pattern speed. The inner spiral is reinforced by regular orbits trapped around the stable, elliptical, periodic orbits of the central family, while the outer system of spiral arms is supported by chaotic orbits. Chaotic orbits are also responsible for a rhomboidal area surrounding the inner barred-spiral region. In general there is a discontinuity between the two spiral structures at the corotation region.

scholarly journals Amplitude of Spiral Arms and Dark Matter

2004 ◽  
Vol 220 ◽  
pp. 313-314
Author(s):  
P. Grosbøl
Keyword(s):  
Dark Matter ◽  
Spiral Galaxies ◽  
Spiral Structure ◽  
Dynamic Effects ◽  
Spiral Arms ◽  
Linear Dynamic ◽  
Total Potential ◽  
Force Perturbation ◽  
Barred Spiral Galaxies ◽  
Armed Spiral

Relative amplitudes and pitch angles for the main two-armed spiral structure in a sample of 54 non-barred spiral galaxies were estimated from K band photometry. A lack of strong, tight patterns was observed which may be caused by non-linear dynamic effects. Assuming that the upper envelope corresponds to a relative radial forcing of ⋐5%, one can estimate the perturbation of the total potential. This suggests that a maximum disk solution is adequate to account for the force perturbation and that no additional dark matter is required.

scholarly journals An HI Study of Two Barred Spiral Galaxies

1996 ◽  
Vol 157 ◽  
pp. 498-500
Author(s):  
E. M. Moore ◽  
S. T. Gottesman
Keyword(s):  
Spiral Galaxies ◽  
Spiral Structure ◽  
Hii Regions ◽  
Type Systems ◽  
Early Type ◽  
Late Type ◽  
Spiral Arms ◽  
Barred Spiral Galaxies ◽  
Pattern Speeds

We have made HI observations of an early type, NGC 1398 (SBab(r)I), and a late type barred system, NGC 3319 (SBc(s)II.4). NGC 1398 is a beautifully symmetric galaxy with a bright stellar bulge, bar and inner ring and tightly wound spiral arms (also classified as an R1 double outer pseudoring). In HI the spiral structure is strong but the center shows a sharp depletion. In contrast, NGC 3319 has an asymmetric appearance and irregular spiral structure. It is rich in its central HI with a gas bar and spiral arms, both of which are highlighted by prominent HII regions. We attempt to determine the pattern speeds of the galaxies and to explore the differences between early and late type systems.

scholarly journals Circumnuclear regions in barred spiral galaxies — I. Near-infrared imaging

2000 ◽  
Vol 317 (2) ◽  
pp. 234-248 ◽  
Author(s):  
D. Pérez-Ramírez ◽  
J. H. Knapen ◽  
R. F. Peletier ◽  
S. Laine ◽  
R. Doyon ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Spiral Galaxies ◽  
Near Infrared Imaging ◽  
Barred Spiral Galaxies

scholarly journals Similarities between Hurricanes and Galaxies: A Short Review

2021 ◽  
Author(s):  
Jim Henry ◽  
Mesut Yurukcu ◽  
George Nnanna
Keyword(s):  
Milky Way ◽  
Spiral Galaxies ◽  
Spiral Structure ◽  
Fibonacci Numbers ◽  
Short Review ◽  
Review Article ◽  
Double Spiral ◽  
Natural Pattern

Universe created with the fundamental laws of science. Nature is lazy and needs to form with the least possible to be perfect. A natural pattern, such as pinecones, sunflowers, pineapples, and cacti, has a double spiral structure. Once we look at these plants' centers, we will see the seeds line up in spirals shape. The number of spirals whirling in each direction will give us the Fibonacci numbers. We can give more examples representing these natural patterns; however, one example is unique and remarkable. The similarities between spiral galaxies- Milky Way and hurricanes. Are they similar in every property or just in shape and rotational movements? What are the similarities between them? This short review article will try to find these questions' answers by reviewing some literature articles. The first part of this article gave some information about hurricanes and galaxies. The second of this article focused on the comparison between hurricanes and galaxies. Finally, we will conclude the article with our remarks.

HI in the Barred Spiral Galaxies NGC 1365 and NGC 1097

1983 ◽  
pp. 233-234 ◽  
Author(s):  
J. M. van der Hulst ◽  
M. P. Ondrechen ◽  
J. H. van Gorkom ◽  
E. Hummel
Keyword(s):  
Spiral Galaxies ◽  
Barred Spiral Galaxies ◽  
Ngc 1365

scholarly journals Infrared Emission from Barred Spiral Galaxies

1996 ◽  
Vol 157 ◽  
pp. 54-62
Author(s):  
Tim G. Hawarden ◽  
J. H. Huang ◽  
Q. S. Gu
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Infrared Emission ◽  
Stellar Radiation ◽  
The Galaxy ◽  
Barred Spiral Galaxies ◽  
Star Formation Regions ◽  
Ir Emission

AbstractAmongst relatively undisturbed spiral galaxies of type ≤ Sc barred morphology is unquestionably associated with powerful mid- and Far-IR emission. On the other hand, even amongst early type galaxies, those with LFIR/LB < 1/3 exhibit no association of high relative FIR luminosity with barred morphology, but some association of IR colors resembling those of star formation regions (SFRs). Amongst systems with LFIR/LB < 0.1 this ratio may be anti-correlated with barredness. It appears that enhanced IR emission from those galaxies whose star formation rate is currently elevated by the the bar translates them into the group with higher FIR-to-optical luminosity ratios. Depletion of extended nearnuclear gas and dust, once the bar has swept up the currently-available supplies, may reduce the fraction of the background stellar radiation field which can be converted to FIR radiation in the inner, most luminous parts of the galaxy. Thus, after the starburst has subsided, such galaxies may be less FIR-luminous than unbarred systems. Several uncertainties remain: it is still not clear whether barred morphology is a necessary condition for the generation of a starburst in an otherwise undisturbed galaxy, while evidence as to the effect of differing bar strengths is conflicting.

scholarly journals The Dark Matter Content of Barred Spiral Galaxies

2004 ◽  
Vol 220 ◽  
pp. 277-278
Author(s):  
Glen Petitpas ◽  
Mousumi Das ◽  
Peter Teuben ◽  
Stuart Vogel
Keyword(s):  
Dark Matter ◽  
Spiral Galaxies ◽  
Velocity Fields ◽  
Matter Content ◽  
Two Dimensional ◽  
Disk Model ◽  
Barred Galaxies ◽  
Preliminary Results ◽  
Nearby Galaxies ◽  
Barred Spiral Galaxies

Two-dimensional velocity fields have been used to determine the dark matter properties of a sample of barred galaxies taken from the BIMA Survey of Nearby Galaxies (SONG). Preliminary results indicate that the maximal disk model is not appropriate in several galaxies in our sample, but higher resolution results will be needed to confirm this.

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