Numerical simulations of interacting gas-rich barred galaxies: vertical impact of small companions

AbstractIn this talk, I will present the result of high resolution numerical simulations of disk galaxies with various bulge/disk ratios evolving isolated, showing that: •Most of migration takes place when the bar strength is high and decreases in the phases of low activity (in agreement with the results by Brunetti et el. 2011, Minchev et al. 2011).•Most of the stars inside the corotation radius (CR) do not migrate in the outer regions, but stay confined in the inner disk, while stars outside CR can migrate either inwards or outwards, diffusing over the whole disk.•Migration is accompanied by significative azimuthal variations in the metallicity distribution, of the order of 0.1 dex for an initial gradient of ~-0.07 dex/kpc.•Boxy bulges are an example of stellar structures whose properties (stellar content, vertical metallicity, [α/Fe] and age gradients, ..) are affected by radial migration (see also Fig. 1).

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Secular evolution in galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306004972 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 19-23 ◽

Cited By ~ 1

Author(s):

F. Combes

Keyword(s):

Star Formation ◽

Numerical Simulations ◽

Significant Role ◽

High Frequency ◽

Central Star ◽

Barred Galaxies ◽

Secular Evolution ◽

Gas Accretion ◽

Bar Formation

AbstractNew observations in favour of a significant role of secular evolution are reviewed: central star formation boosted in pseudo-bulge barred galaxies, relations between bulge and disk, evidence for rejuvenated bulges. Numerical simulations have shown that secular evolution can occur through a cycle of bar formation and destruction, in which the gas plays a major role. Since bars are weakened or destroyed in gaseous disks, the high frequency of bars observed today requires external cold gas accretion, to replenish the disk and allow a new bar formation. The rate of gas accretion from external filaments is compatible with what is observed in cosmological simulations.

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Cosmic Evolution of Barred Galaxies up to z ∼ 0.84

The Astrophysical Journal ◽

10.3847/1538-4357/ac2300 ◽

2021 ◽

Vol 922 (2) ◽

pp. 196

Author(s):

Taehyun Kim ◽

E. Athanassoula ◽

Kartik Sheth ◽

Albert Bosma ◽

Myeong-Gu Park ◽

...

Keyword(s):

Numerical Simulations ◽

Cosmic Time ◽

Stellar Mass ◽

Barred Galaxies ◽

Cosmic Evolution ◽

Strong Disagreement ◽

The Galaxy ◽

Stellar Masses ◽

Scale Length

Abstract We explore the cosmic evolution of the bar length, strength, and light deficit around the bar for 379 barred galaxies at 0.2 < z ≤ 0.835 using F814W images from the COSMOS survey. Our sample covers galaxies with stellar masses 10.0 ≤ log ( M * / M ⊙ ) ≤ 11.4 and various Hubble types. The bar length is strongly related to the galaxy mass, the disk scale length (h), R 50, and R 90, where the last two are the radii containing 50% and 90% of total stellar mass, respectively. Bar length remains almost constant, suggesting little or no evolution in bar length over the last 7 Gyr. The normalized bar lengths (R bar/h, R bar/R 50, and R bar/R 90) do not show any clear cosmic evolution. Also, the bar strength (A 2 and Q b ) and the light deficit around the bar reveal little or no cosmic evolution. The constancy of the normalized bar lengths over cosmic time implies that the evolution of bars and of disks is strongly linked over all times. We discuss our results in the framework of predictions from numerical simulations. We conclude there is no strong disagreement between our results and up-to-date simulations.

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Studying Barred Galaxies by Means of Numerical Simulations

Astrophysics and Space Science Proceedings - Highlights of Spanish Astrophysics V ◽

10.1007/978-3-642-11250-8_56 ◽

2010 ◽

pp. 313-313

Author(s):

Inma Martinez-Valpuesta

Keyword(s):

Numerical Simulations ◽

Barred Galaxies

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Air entrapment and bubble formation during droplet impact onto a single cubic pillar

Scientific Reports ◽

10.1038/s41598-021-97376-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Weibo Ren ◽

Patrick Foltyn ◽

Anne Geppert ◽

Bernhard Weigand

Keyword(s):

Numerical Simulations ◽

Morphological Changes ◽

Bubble Formation ◽

Three Dimensional ◽

Air Entrapment ◽

Droplet Dynamics ◽

Entrapped Air ◽

The Impact ◽

Insight Into ◽

Vertical Impact

AbstractWe study the vertical impact of a droplet onto a cubic pillar of comparable size placed on a flat surface, by means of numerical simulations and experiments. Strikingly, during the impact a large volume of air is trapped around the pillar side faces. Impingement upon different positions of the pillar top surface strongly influences the size and the position of the entrapped air. By comparing the droplet morphological changes during the impact from both computations and experiments, we show that the direct numerical simulations, based on the Volume of Fluid method, provide additional and new insight into the droplet dynamics. We elucidate, with the computational results, the three-dimensional air entrapment process as well as the evolution of the entrapped air into bubbles.

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Direct Numerical Simulations of Gas–Liquid Multiphase Flows

10.1017/cbo9780511975264 ◽

2001 ◽

Cited By ~ 151

Author(s):

Grétar Tryggvason ◽

Ruben Scardovelli ◽

Stéphane Zaleski

Keyword(s):

Numerical Simulations ◽

Multiphase Flows ◽

Direct Numerical Simulations

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Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038023 ◽

2020 ◽

Vol 640 ◽

pp. A53

Author(s):

L. Löhnert ◽

S. Krätschmer ◽

A. G. Peeters

Keyword(s):

Growth Rate ◽

Numerical Simulations ◽

Accretion Disks ◽

Gravitational Instability ◽

Turbulent Viscosity ◽

Radial Distance ◽

Maximum Growth ◽

Wave Number ◽

Radiative Cooling ◽

Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

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