Dense Core Formation in Supersonic Turbulent Converging Flows

Gong, Hao; Ostriker, Eve C.

doi:10.1088/0004-637x/729/2/120

Cited by 90 publications

(115 citation statements)

References 116 publications

(160 reference statements)

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“…In the current paradigm of star formation, dense cores form in velocity-coherent filamentary clouds formed from converging turbulent flows (e.g., Elmegreen 2007;Gong & Ostriker 2011). It has been proposed that the higher velocity dispersion of the YSOs could arise due to magnetic fields constraining the dense cores or the global collapse of the cluster that would convert gravitational potential energy to kinetic energy and thereby increase the probability of stellar encounters (André et al 2007;Foster et al 2015).…”

Section: Discussionmentioning

confidence: 99%

Relative Proper Motions in the Rho Ophiuchi Cluster

Wilking

Vrba

Sullivan

2015

ApJ

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Near-infrared images optimized for astrometry have been obtained for four fields in the high-density L 1688 cloud core over a 12 year period. The targeted regions include deeply embedded young stellar objects (YSOs) and very low luminosity objects too faint and/or heavily veiled for spectroscopy. Relative proper motions in R.A. and decl. were computed for 111 sources and again for a subset of 65 YSOs, resulting in a mean proper motion of (0,0) for each field. Assuming each field has the same mean proper motion, YSOs in the four fields were combined to yield estimates of the velocity dispersions in R.A. and decl. that are consistent with 1.0 km s −1 . These values appear to be independent of the evolutionary state of the YSOs. The observed velocity dispersions are consistent with the dispersion in radial velocity derived for optically visible YSOs at the periphery of the cloud core and are consistent with virial equilibrium. The higher velocity dispersion of the YSOs in the plane of the sky relative to that of dense cores may be a consequence of stellar encounters due to dense cores and filaments fragmenting to form small groups of stars or the global collapse of the L 1688 cloud core. An analysis of the differential magnitudes of objects over the 12 year baseline has not only confirmed the near-infrared variability for 29 YSOs established by prior studies, but has also identified 18 new variability candidates. Four of these have not been previously identified as YSOs and may be newly identified cluster members.

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Section: Discussionmentioning

confidence: 99%

Relative Proper Motions in the Rho Ophiuchi Cluster

Wilking

Vrba

Sullivan

2015

ApJ

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“…flows (e.g., Elmegreen 2007;Gong & Ostriker 2011). It has been proposed that the higher velocity dispersion of the YSOs could arise owing to magnetic fields constraining the dense cores , or the global collapse of the cluster that would convert gravitational potential energy into kinetic energy and thereby increase the probability of stellar encounters (André et al 2007;Foster et al 2015).…”

Section: Stellar Dense-cores and Diffuse-gas Velocity Dispersionsmentioning

confidence: 99%

TheGaia-ESO Survey: Dynamical analysis of the L1688 region in Ophiuchus

Rigliaco

Wilking

Meyer

et al. 2016

A&A

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The Gaia ESO Public Spectroscopic Survey (GES) is providing the astronomical community with high-precision measurements of many stellar parameters including radial velocities (RVs) of stars belonging to several young clusters and star-forming regions. One of the main goals of the young cluster observations is to study their dynamical evolution and provide insight into their future, revealing whether they will eventually disperse to populate the field rather than evolve into bound open clusters. In this paper we report the analysis of the dynamical state of L1688 in the ρ Ophiuchi molecular cloud using the dataset provided by the GES consortium. We performed the membership selection of the more than 300 objects observed. Using the presence of the lithium absorption and the location in the Hertzspung-Russell diagram, we identify 45 already known members and two new association members. We provide accurate RVs for all 47 confirmed members. A dynamical analysis, after accounting for unresolved binaries and errors, shows that the stellar surface population of L1688 has a velocity dispersion σ ∼ 1.14 ± 0.35 km s −1 that is consistent with being in virial equilibrium and is bound with a ∼80% probability. We also find a velocity gradient in the stellar surface population of ∼1.0 km s −1 pc −1 in the northwest-southeast direction, which is consistent with that found for the pre-stellar dense cores, and we discuss the possibility of sequential and triggered star formation in L1688.

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“…As in Gong & Ostriker (2011), we adopt the isothermal approximation. The isothermal sound speed at a temperature T is…”

Section: Planar Converging Supersonic Flow With Sink Particlesmentioning

confidence: 99%

IMPLEMENTATION OF SINK PARTICLES IN THE ATHENA CODE

Gong

Ostriker

2012

ApJS

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We describe implementation and tests of sink particle algorithms in the Eulerian grid-based code Athena. Introduction of sink particles enables long-term evolution of systems in which localized collapse occurs, and it is impractical (or unnecessary) to resolve the accretion shocks at the centers of collapsing regions. We discuss similarities and differences of our methods compared to other implementations of sink particles. Our criteria for sink creation are motivated by the properties of the Larson-Penston collapse solution. We use standard particlemesh methods to compute particle and gas gravity together. Accretion of mass and momenta onto sinks is computed using fluxes returned by the Riemann solver. A series of tests based on previous analytic and numerical collapse solutions is used to validate our method and implementation. We demonstrate use of our code for applications with a simulation of planar converging supersonic turbulent flow, in which multiple cores form and collapse to create sinks; these sinks continue to interact and accrete from their surroundings over several Myr.

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Dense Core Formation in Supersonic Turbulent Converging Flows

Cited by 90 publications

References 116 publications

Relative Proper Motions in the Rho Ophiuchi Cluster

Relative Proper Motions in the Rho Ophiuchi Cluster

TheGaia-ESO Survey: Dynamical analysis of the L1688 region in Ophiuchus

IMPLEMENTATION OF SINK PARTICLES IN THE ATHENA CODE

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