Simulations of dual morphology in spiral galaxies

Berman, S. L.

doi:10.1051/0004-6361:20031467

Cited by 3 publications

(2 citation statements)

References 28 publications

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“…Spiral structure formation in galaxies is important tasks of their physics. There are numerous mechanisms of spiral structure formation such as central stellar bar [35], swing amplification mechanism [4], gravitational instability [22], interactions with another galaxies [38], hydrodynamical instabilities [8], induced star formation in flocculent galaxies [3].…”

Section: Dark Massive Halo and Spiral Structurementioning

confidence: 99%

Dynamics of gaseous disks in a non-axisymmetric dark halo

et al. 2012

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The dynamics of a galactic disk in a non-axisymmetric (triaxial) dark halo is studied in detail using high-resolution, numerical, hydrodynamical models. A long-lived, two-armed spiral pattern is generated for a wide range of parameters. The spiral structure is global, and the number of turns can be two or three, depending on the model parameters. The morphology and kinematics of the spiral pattern are studied as functions of the halo and disk parameters. The spiral structure rotates slowly, and its angular velocity varies quasi-periodically. Models with differing relative halo masses, halo semi-axis ratios, distributions of matter in the disk, Mach numbers in the gaseous component, and angular rotational velocities of their halos are considered.

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Section: Dark Massive Halo and Spiral Structurementioning

confidence: 99%

Dynamics of gaseous disks in a non-axisymmetric dark halo

et al. 2012

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“…18 Nevertheless, gravity is a long-range force, and all the non-axisymmetric contributions must be taken into account for local potential minimum determinations. Thus, the local potential does not necessarily coincide with the local density of old stars (see, e.g., Zhang 1996;Berman 2003;Gittins & Clarke 2004;Zhang & Buta 2007;Buta & Zhang 2009), and the expected locations of the dust lanes must follow the potential, rather than the K-band intensity.…”

Section: Characteristics Of Observed Color Gradientsmentioning

confidence: 99%

The Relation Between Dynamics and Star Formation in Barred Galaxies

Martínez-García

González-Lópezlira²

2011

ApJ

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We analyze optical and near-infrared data of a sample of 11 barred spiral galaxies, in order to establish a connection between star formation and bar/spiral dynamics. We find that 22 regions located in the bars, and 20 regions in the spiral arms beyond the end of the bar present azimuthal color/age gradients that may be attributed to star formation triggering. Assuming a circular motion dynamic model, we compare the observed age gradient candidates with stellar populations synthesis models. A link can then be established with the disk dynamics that allows us to obtain parameters like the pattern speed of the bar or spiral, as well as the positions of resonance radii. We subsequently compare the derived pattern speeds with those expected from theoretical and observational results in the literature (e.g., bars ending near corotation). We find a tendency to overestimate bar pattern speeds derived from color gradients in the bar at small radii, away from corotation; this trend can be attributed to non-circular motions of the young stars born in the bar region. In spiral regions, we find that ∼ 50% of the color gradient candidates are "inverse", i.e., with the direction of stellar aging contrary to that of rotation. The other half of the gradients found in spiral arms have stellar ages that increase in the same sense as rotation. Of the 9 objects with gradients in both bars and spirals, 6 (67%) appear to have a bar and a spiral with similar Ω p , while 3 (33%) do not.

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Unlocking the Plants’ Distribution in a Fractal Space

HE,

YANG,

et al. 2023

Fractals

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All known planets orbit the Sun so harmoniously that the entire Universe is believed to behave in a rhythmical and fractal way. Titius–Bode law is the main theoretical tool for planetary orbit description. Here we show that planetary sequence follows the Fibonacci-like prime sequence, and we introduce two gravitational spirals to predict orbits for solar members orbiting the Sun. Furthermore, we predict two hypothetical planets as far as 1500 AU and 2300 AU from the Sun, respectively, in our solar system, and some unknown planets in extrasolar planetary systems. Our planetary sequence demonstrates the possible frontier of our solar system, and the theory is also valid for other star systems and planetary systems, giving a simple way to finding the most possible adjacent unknown planets or moons near a known one. We anticipate our sequence can be more sophisticatedly used to search for unknown Universes and to depict the cosmos fully and exclusively, and we conclude that our whole Universe is of fractal property and all celestial bodies are distributed according to Fibonacci sequence.

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Simulations of dual morphology in spiral galaxies

Cited by 3 publications

References 28 publications

Dynamics of gaseous disks in a non-axisymmetric dark halo

Dynamics of gaseous disks in a non-axisymmetric dark halo

The Relation Between Dynamics and Star Formation in Barred Galaxies

Unlocking the Plants’ Distribution in a Fractal Space

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