The influence of numerical parameters on tidally triggered bar formation

Gabbasov, Ruslan; Rodríguez‐Meza, M. A.; Klapp, Jaime; Cervantes-Cota, Jorge L.

doi:10.1051/0004-6361:20054254

Cited by 22 publications

(45 citation statements)

References 54 publications

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“…Our tests varying the number of particles, their ratio and ε confirmed our previous findings (Gabbasov et al 2006) and the results described by Farouki & Salpeter (1994), namely, that unequal mass particles lead to excessive disk heating and models are prone to bar formation. Despite the higher cost paid for increased halo resolution the models are more stable and lead to richer tidal structures being produced in collision simulations below.…”

Section: Galaxy Modelssupporting

confidence: 89%

An Interaction Scenario of the Galaxy Pair NGC 3893/96 (Kpg 302): A Single Passage?

Gabbasov

Rosado

Klapp

2014

ApJ

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Using the data obtained previously from Fabry-Perot interferometry, we study the orbital characteristics of the interacting pair of galaxies KPG 302 with the aim to estimate a possible interaction history, the conditions necessary for the spiral arms formation and initial satellite mass. We found by performing N-body/SPH simulations of the interaction that a single passage can produce a grand design spiral pattern in less than 1 Gyr. Although we reproduce most of the features with the single passage, the required satellite to host mass ratio should be ∼ 1 : 5, which is not confirmed by the dynamical mass estimate made from the measured rotation curve. We conclude that a more realistic interaction scenario would require several passages in order to explain the mass ratio discrepancy.

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Section: Galaxy Modelssupporting

confidence: 89%

An Interaction Scenario of the Galaxy Pair NGC 3893/96 (Kpg 302): A Single Passage?

Gabbasov

Rosado

Klapp

2014

ApJ

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“…Both components consisted of 4×10 6 particles. Such a large number of particles is believed to be sufficient to follow the interaction and bar evolution reliably (Gabbasov et al 2006;Dubinski et al 2009), as well as the effect of the gas (Patsis & Athanassoula 2000).…”

Section: Initial Conditionsmentioning

confidence: 99%

Tidally Induced Bars in Gas-rich Dwarf Galaxies Orbiting the Milky Way

Gajda

Łokas

Athanassoula

2018

ApJ

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Bars in galaxies may form not only through instability, but also as a result of an interaction with another galaxy. In particular, they may appear in disky dwarf galaxies interacting with Milky Way-like galaxies. Here we report the results of N -body/SPH simulations of such dwarfs orbiting in the static potential of a larger galaxy. We used several models of the dwarf galaxy, all of the same mass, but covering a large range of gas fractions: 0, 30 and 70%. We also tested the impact of subgrid star formation processes. In all cases bars of similar length formed in the stellar disk of the dwarfs at the first pericenter passage. However, unexpectedly, the gaseous component remained approximately axisymmetric and unaffected by the bar potential. The bar properties did not change significantly between two consecutive pericenters. The impact of the later encounters with the host depends strongly on the exact orientation of the bar at the pericenter. When the bar is spun up by the tidal force torque, it is also shortened. Conversely, if it is slowed down, it gets longer. In the models with a low gas fraction the bars were more pronounced and survived until the end of the simulations, while in the dwarfs with a high gas fraction the bars were destroyed after the second or third pericenter passage. In terms of the ratio of the corotation radius to the bar length, the bars are slow, and remain so independently of the encounters with the host.

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“…Following Gabbasov et al (2006), some empirical formulas are known to assign a value to i in order to minimize errors in the calculation of the gravitational force on a particle i of the mass m i . However, Gadget2 fixes the value of i for each timestep using the minimum smoothing length value of all particles, that is, if h min = min(h i ) for i = 1, 2...N, then i = h min .…”

Section: Evolution Codementioning

confidence: 99%

The gravitational collapse of Plummer protostellar clouds

Arreaga‐García¹,

Klapp-Escribano²,

Gómez-Ramírez³

2010

A&A

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The growing observational evidence that main-sequence and pre-main-sequence protostars are found in binary and multiple systems suggests that they are formed by a fragmentation of collapsing molecular cloud cores. In this paper we present the results of a set of numerical simulations aimed to study the gravitational collapse and fragmentation of a centrally condensed cloud with a nearly flat central density region and a surrounding gas envelope. In order to describe this cloud structure, we use the Plummer radial density profile which satisfies the observed fact that protostellar clouds have a flat central density profile in their innermost region. We consider the cloud to be made of molecular hydrogen and describe the thermodynamics with a single barotropic equation of state, which includes a critical density ρ crit as a unique free parameter that determines a thermodynamical change on the collapsing gas: from an isothermal to an adiabatic regime. In this paper we consider four different values for the initial radius R c of the cloud, ranging from 2675 to 19 913 AU. In the models, for each ratio R c /R 0 of the cloud to core radius, we use two critical density values: ρ crit = 5.0 × 10 −14 and 5.0 × 10 −12 gr cm −3 . When the adiabatic change regime starts earlier, we find interesting gas structures as a result of the collapse, although these structures are different according to the initial mass content of the envelope and the initial angular velocity of the cloud. When the thermodynamical change occurs later, i.e., for ρ crit = 5.0 × 10 −12 gr cm −3 , we observe that the previously found structure is almost erased to give place instead to a single clump of gas without any adorning spiral arms. In general, we find that as the extension of the envelope mass increases, the possibility of a model to produce a multiple system decreases. This is a result of the initial configuration of our models, namely that with bigger envelopes their cores have a lower ratio of rotational to gravitational energy β 0 , a lower ratio of thermal plus rotational to gravitational energy α 0 + β 0 , and a lower angular velocity Ω 0 , which induces a stronger collapse which in turn contributes to the destruction of the structure that is formed during the initial phases of the collapse. Thus in a sufficient quantity rotational energy is crucial for the fragmentation to occur and survive.

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The influence of numerical parameters on tidally triggered bar formation

Cited by 22 publications

References 54 publications

An Interaction Scenario of the Galaxy Pair NGC 3893/96 (Kpg 302): A Single Passage?

An Interaction Scenario of the Galaxy Pair NGC 3893/96 (Kpg 302): A Single Passage?

Tidally Induced Bars in Gas-rich Dwarf Galaxies Orbiting the Milky Way

The gravitational collapse of Plummer protostellar clouds

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