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The dynamical evolution of molecular clouds near the Galactic Centre -- III. Tidally--induced star formation in protocluster clouds. / Dale, James E.; Kruijssen, J. M. Diederik; Longmore, S. N.

In: Monthly Notices of the Royal Astronomical Society, Vol. 486, No. 3, 02.04.2019, p. 3307–3326.

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@article{ccea16b19bcd4760863e6bdebcb70930,
title = "The dynamical evolution of molecular clouds near the Galactic Centre -- III. Tidally--induced star formation in protocluster clouds",
abstract = "As part of a series of papers aimed at understanding the evolution of the Milky Way's Central Molecular Zone (CMZ), we present hydrodynamical simulations of turbulent molecular clouds orbiting in an accurate model of the gravitational potential extant there. We consider two sets of model clouds differing in the energy content of their velocity fields. In the first, self-virialized set, the turbulent kinetic energies are chosen to be close in magnitude to the clouds' self-gravitational potential energies. Comparison with isolated clouds evolving without an external potential shows that the self-virialized clouds are unable to withstand the compressive tidal field of the CMZ and rapidly collapse, forming stars much faster and reaching gas exhaustion after a small fraction of a Galactocentric orbit. In the second, tidally virialized, set of simulations, the clouds' turbulent kinetic energies are in equilibrium with the external tidal field. These models are better supported against the field and the stronger turbulence suppresses star formation. Our results strongly support the inference that anomalously low star formation rates in the CMZ are due primarily to high velocity dispersions in the molecular gas. The clouds follow open, eccentric orbits oscillating in all three spatial coordinates. We examine the consequences of the orbital dynamics, particularly pericentre passage, by performing companion simulations of clouds on circular orbits. The increased tidal forces at pericentre produce transient accelerations in star formation rates of at most a factor of 2.7. Our results demonstrate that modelling star formation in galactic centres requires the inclusion of tidal forces.",
keywords = "astro-ph.GA, stars: formation, Galaxy: centre, ISM: evolution, galaxies: ISM, ISM: kinematics and dynamics, ISM: clouds",
author = "Dale, {James E.} and Kruijssen, {J. M. Diederik} and Longmore, {S. N.}",
note = "{\textcopyright} 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.",
year = "2019",
month = apr,
day = "2",
doi = "10.1093/mnras/stz888",
language = "English",
volume = "486",
pages = "3307–3326",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "3",

}

RIS

TY - JOUR

T1 - The dynamical evolution of molecular clouds near the Galactic Centre -- III. Tidally--induced star formation in protocluster clouds

AU - Dale, James E.

AU - Kruijssen, J. M. Diederik

AU - Longmore, S. N.

N1 - © 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.

PY - 2019/4/2

Y1 - 2019/4/2

N2 - As part of a series of papers aimed at understanding the evolution of the Milky Way's Central Molecular Zone (CMZ), we present hydrodynamical simulations of turbulent molecular clouds orbiting in an accurate model of the gravitational potential extant there. We consider two sets of model clouds differing in the energy content of their velocity fields. In the first, self-virialized set, the turbulent kinetic energies are chosen to be close in magnitude to the clouds' self-gravitational potential energies. Comparison with isolated clouds evolving without an external potential shows that the self-virialized clouds are unable to withstand the compressive tidal field of the CMZ and rapidly collapse, forming stars much faster and reaching gas exhaustion after a small fraction of a Galactocentric orbit. In the second, tidally virialized, set of simulations, the clouds' turbulent kinetic energies are in equilibrium with the external tidal field. These models are better supported against the field and the stronger turbulence suppresses star formation. Our results strongly support the inference that anomalously low star formation rates in the CMZ are due primarily to high velocity dispersions in the molecular gas. The clouds follow open, eccentric orbits oscillating in all three spatial coordinates. We examine the consequences of the orbital dynamics, particularly pericentre passage, by performing companion simulations of clouds on circular orbits. The increased tidal forces at pericentre produce transient accelerations in star formation rates of at most a factor of 2.7. Our results demonstrate that modelling star formation in galactic centres requires the inclusion of tidal forces.

AB - As part of a series of papers aimed at understanding the evolution of the Milky Way's Central Molecular Zone (CMZ), we present hydrodynamical simulations of turbulent molecular clouds orbiting in an accurate model of the gravitational potential extant there. We consider two sets of model clouds differing in the energy content of their velocity fields. In the first, self-virialized set, the turbulent kinetic energies are chosen to be close in magnitude to the clouds' self-gravitational potential energies. Comparison with isolated clouds evolving without an external potential shows that the self-virialized clouds are unable to withstand the compressive tidal field of the CMZ and rapidly collapse, forming stars much faster and reaching gas exhaustion after a small fraction of a Galactocentric orbit. In the second, tidally virialized, set of simulations, the clouds' turbulent kinetic energies are in equilibrium with the external tidal field. These models are better supported against the field and the stronger turbulence suppresses star formation. Our results strongly support the inference that anomalously low star formation rates in the CMZ are due primarily to high velocity dispersions in the molecular gas. The clouds follow open, eccentric orbits oscillating in all three spatial coordinates. We examine the consequences of the orbital dynamics, particularly pericentre passage, by performing companion simulations of clouds on circular orbits. The increased tidal forces at pericentre produce transient accelerations in star formation rates of at most a factor of 2.7. Our results demonstrate that modelling star formation in galactic centres requires the inclusion of tidal forces.

KW - astro-ph.GA

KW - stars: formation

KW - Galaxy: centre

KW - ISM: evolution

KW - galaxies: ISM

KW - ISM: kinematics and dynamics

KW - ISM: clouds

UR - http://www.scopus.com/inward/record.url?scp=85068960011&partnerID=8YFLogxK

U2 - 10.1093/mnras/stz888

DO - 10.1093/mnras/stz888

M3 - Article

VL - 486

SP - 3307

EP - 3326

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -