Dynamics of gaseous disks in a non-axisymmetric dark halo

Хоперсков, А. В.; Eremin, M. A.; Khoperskov, Sergey; Butenko, Maria; Morozov, A. G.

doi:10.1134/s1063772912010039

Cited by 22 publications

(20 citation statements)

References 61 publications

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“…A non-axially symmetric halo significantly affect both the stellar and gas subsystem dynamics. In numerical models, a long-lived quasi-steady spiral structure forms [164]. The twoarm wave encompasses almost the entire gas disk but the very center, in which more complex structures are observed ( Fig.…”

Section: Dark Halo Triaxiality and Spiral Structure Of The Diskmentioning

confidence: 99%

Dark matter in galaxies

Засов¹,

Saburova²,

Хоперсков³

et al. 2017

Phys.-Usp.

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Dark matter in galaxies, its abundance, and its distribution remain a subject of long-standing discussion, especially in view of the fact that neither dark matter particles nor dark matter bodies have yet been found. Experts' opinions range from a very large number of completely dark galaxies exist to nonbaryonic dark matter does not exist at all in any significant amounts. We discuss astronomical evidence for the existence of dark matter and its connection with visible matter and examine attempts to estimate its mass and distribution in galaxies from photometry, dynamics, gravitational lensing, and other observations (the cosmological aspects of the existence of dark matter are not considered in this review). In our view, the presence of dark matter in and around galaxies is a well-established fact. We conclude with an overview of mechanisms by which a dark halo can influence intragalactic processes.Comment: 82 pages, 35 figure

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Section: Dark Halo Triaxiality and Spiral Structure Of The Diskmentioning

confidence: 99%

Dark matter in galaxies

Засов¹,

Saburova²,

Хоперсков³

et al. 2017

Phys.-Usp.

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“…The density wave picture of spiral arms popularised by the works of Lin & Shu (1964), Kalnajs (1973), and Bertin et al (1989) still holds as the canonical theory. However, there are many other competing theories that postulate spiral arms behave as dynamical transients (Sellwood & Carlberg 1984;Elmegreen & Thomasson 1993), can be created by bar rotation (Contopoulos & Papayannopoulos 1980;Athanassoula 1992), tidal interactions (Toomre & Toomre 1972;Elmegreen et al 1991), and rotations of non-axisymmetric dark matter haloes (Dubinski & Chakrabarty 2009;Khoperskov et al 2012). The emerging paradigm seems to be that there may not be a grand underlying theory for all spirals; and that each theory has its own merits and weaknesses (e.g.…”

Section: Introductionmentioning

confidence: 99%

Star formation and ISM morphology in tidally induced spiral structures

Pettitt

Tasker

Wadsley

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Tidal encounters are believed to be one of the key drivers of galactic spiral structure in the Universe. Such spirals are expected to produce different morphological and kinematic features compared to density wave and dynamic spiral arms. In this work, we present high resolution simulations of a tidal encounter of a small mass companion with a disc galaxy. Included are the effects of gas cooling and heating, star formation and stellar feedback. The structure of the perturbed disc differs greatly from the isolated galaxy, showing clear spiral features that act as sites of new star formation, and displaying interarm spurs. The two arms of the galaxy, the bridge and tail, appear to behave differently; with different star formation histories and structure. Specific attention is focused on offsets between gas and stellar spiral features which can be directly compared to observations. We find that some offsets do exist between different media, with gaseous arms appearing mostly on the convex side of the stellar arms, though the exact locations appear highly time dependent. These results further highlight the differences between tidal spirals and other theories of arm structure.

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“…In these scenarios, the role of dark matter is not clear. On the other hand, it is generally believed that, in the presence of a triaxial (i.e., non-axisymmetric) distribution of dark matter (Khoperskov et al 2012;Valenzuela et al 2014), disc-halo interactions could generate spiral structure. However, for the majority of galaxies our knowledge of the three-dimensional distribution of dark matter is quite poor.…”

Section: Introductionmentioning

confidence: 99%

Spiral density waves in the outer galactic gaseous discs

Khoperskov

Bertin

2015

Monthly Notices of the Royal Astronomical Society

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Deep HI observations of the outer parts of disc galaxies demonstrate the frequent presence of extended, well-developed spiral arms far beyond the optical radius. To understand the nature and the origin of such outer spiral structure, we investigate the propagation in the outer gaseous disc of large-scale spiral waves excited in the bright optical disc. Using hydrodynamical simulations, we show that non-axisymmetric density waves, penetrating in the gas through the outer Lindblad resonance, can exhibit relatively regular spiral structures outside the bright optical stellar disc. For lowamplitude structures, the results of numerical simulations match the predictions of a simple WKB linear theory. The amplitude of spiral structure increases rapidly with radius. Beyond ≈ 2 optical radii, spirals become nonlinear (the linear theory becomes quantitatively and qualitatively inadequate) and unstable to Kelvin-Helmholtz instability. In numerical simulations, in models for which gas is available very far out, spiral arms can extend out to 25 disc scale-lengths. A comparison between the properties of the models we have investigated and the observed properties of individual galaxies may shed light into the problem of the amount and distribution of dark matter in the outer halo.

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Dynamics of gaseous disks in a non-axisymmetric dark halo

Cited by 22 publications

References 61 publications

Dark matter in galaxies

Dark matter in galaxies

Star formation and ISM morphology in tidally induced spiral structures

Spiral density waves in the outer galactic gaseous discs

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