Inter-cluster velocity structures of star cluster complexes

2019 ◽  
Vol 14 (S351) ◽  
pp. 197-199
Author(s):  
Michiko S. Fujii
Keyword(s):  
Molecular Clouds ◽  
Star Clusters ◽  
Star Cluster ◽  
Velocity Data ◽  
High Quality ◽  
Cluster Systems ◽  
Cluster Complexes ◽  
Individual Stars ◽  
Data Release ◽  
Maximum Cluster

AbstractStar clusters are often born as star-cluster systems, which include several stellar clumps. Such star-cluster complexes could have formed from turbulent molecular clouds. Since Gaia Data Release 2 provided us high quality velocity data of individual stars in known star-cluster complexes, we now can compare the velocity structures of the observed star-cluster complexes with simulated ones. We performed a series of N-body simulations for the formation of star-cluster complexes starting from turbulent molecular clouds. We measured the inter-cluster velocity dispersions of our simulated star-cluster complexes and compared them with the Carina region and NGC 2264. We found that the Carina region and NGC 2264 formed from molecular clouds with a mass of ∼4 × 105M⊙ and ∼4 × 104M⊙, respectively. In our simulations, we also found that the maximum cluster mass (Mc,max) in the complex follows ${M_{{\rm{c}},{\rm{max}}}} = 0.{\rm{2}}0M_g^{0.76}$, where Mg is the initial gas mass.

scholarly journals Spectroscopic study of formation, evolution and interaction of M31 and M33 with star clusters

2014 ◽  
Vol 10 (S312) ◽  
pp. 201-202 ◽  
Author(s):  
Zhou Fan ◽  
Yanbin Yang
Keyword(s):  
Globular Clusters ◽  
Stellar Population ◽  
Local Group ◽  
Spiral Galaxies ◽  
Star Clusters ◽  
Star Cluster ◽  
Physical Parameters ◽  
Cluster Systems ◽  
Nearby Galaxies ◽  
Formation And Evolution

AbstractThe recent studies show that the formation and evolution process of the nearby galaxies are still unclear. By using the Canada France Hawaii Telescope (CFHT) 3.6m telescope, the PanDAS shows complicated substructures (dwarf satellite galaxies, halo globular clusters, extended clusters, star streams, etc.) in the halo of M31 to ~150 kpc from the center of galaxy and M31-M33 interaction has been studied. In our work, we would like to investigate formation, evolution and interaction of M31 and M33, which are the nearest two spiral galaxies in Local Group. The star cluster systems of the two galaxies are good tracers to study the dynamics of the substructures and the interaction. Since 2010, the Xinglong 2.16m, Lijiang 2.4m and MMT 6.5m telescopes have been used for our spectroscopic observations. The radial velocities and Lick absorption-line indices can thus be measured with the spectroscopy and then ages, metallicities and masses of the star clusters can be fitted with the simple stellar population models. These parameters could be used as the input physical parameters for numerical simulations of M31-M33 interaction.

scholarly journals The Influence of Gas Expulsion on the Evolution of Star Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 36-40
Author(s):  
H. Baumgardt ◽  
P. Kroupa
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Three Dimensional ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Star Cluster ◽  
Dissolution Mechanism ◽  
Large Set ◽  
Cluster Systems

AbstractWe present new results on the dynamical evolution and dissolution of star clusters due to residual gas expulsion and the effect this has on the mass function and other properties of star cluster systems. To this end, we have carried out a large set of N-body simulations, varying the star formation efficiency, gas expulsion time scale and strength of the external tidal field, obtaining a three-dimensional grid of models which can be used to predict the evolution of individual star clusters or whole star cluster systems by interpolating between our runs. When applied to the Milky Way globular cluster system, we find that gas expulsion is the main dissolution mechanism for star clusters, destroying about 80% of all clusters within a few 10s of Myers. Together with later dynamical evolution, it seems possible to turn an initial power-law mass function into a log-normal one with properties similar to what has been observed for the Milky Way globular clusters.

scholarly journals Simulating star clusters across cosmic time – II. Escape fraction of ionizing photons from molecular clouds

2020 ◽  
Vol 492 (4) ◽  
pp. 4858-4873 ◽  
Author(s):  
Chong-Chong He ◽  
Massimo Ricotti ◽  
Sam Geen
Keyword(s):  
Star Formation ◽  
Ionizing Radiation ◽  
Molecular Clouds ◽  
Globular Clusters ◽  
Compact Star ◽  
Star Clusters ◽  
Cosmic Time ◽  
Star Cluster ◽  
Star Forming ◽  
Radiation Feedback

ABSTRACT We calculate the hydrogen- and helium-ionizing radiation escaping star-forming molecular clouds, as a function of the star cluster mass and compactness, using a set of high-resolution radiation-magnetohydrodynamic simulations of star formation in self-gravitating, turbulent molecular clouds. In these simulations, presented in He et al., the formation of individual massive stars is well resolved, and their UV radiation feedback and lifetime on the main sequence are modelled self-consistently. We find that the escape fraction of ionizing radiation from molecular clouds, $\langle f_{\rm esc}^{\scriptscriptstyle \rm MC}\rangle$ , decreases with increasing mass of the star cluster and with decreasing compactness. Molecular clouds with densities typically found in the local Universe have negligible $\langle f_{\rm esc}^{\scriptscriptstyle \rm MC}\rangle$ , ranging between $0.5{{\ \rm per\ cent}}$ and $5{{\ \rm per\ cent}}$. 10 times denser molecular clouds have $\langle f_{\rm esc}^{\scriptscriptstyle \rm MC}\rangle$ $\approx 10{{\ \rm per\ cent}}{-}20{{\ \rm per\ cent}}$, while 100× denser clouds, which produce globular cluster progenitors, have $\langle f_{\rm esc}^{\scriptscriptstyle \rm MC}\rangle$ $\approx 20{{\ \rm per\ cent}}{-}60{{\ \rm per\ cent}}$. We find that $\langle f_{\rm esc}^{\scriptscriptstyle \rm MC}\rangle$ increases with decreasing gas metallicity, even when ignoring dust extinction, due to stronger radiation feedback. However, the total number of escaping ionizing photons decreases with decreasing metallicity because the star formation efficiency is reduced. We conclude that the sources of reionization at z > 6 must have been very compact star clusters forming in molecular clouds about 100× denser than in today’s Universe, which lead to a significant production of old globular clusters progenitors.

scholarly journals Central Densities of Star Clusters in the Magellanic Clouds

1996 ◽  
Vol 174 ◽  
pp. 335-336 ◽  
Author(s):  
M. Kontizas ◽  
D. Gouliermis ◽  
E. Kontizas
Keyword(s):  
Total Mass ◽  
Star Clusters ◽  
Star Cluster ◽  
Magellanic Clouds ◽  
Cluster System ◽  
Galactocentric Distance ◽  
Cluster Systems ◽  
Image Position ◽  
Young Old ◽  
Parent Galaxy

The way star cluster systems in galaxies are forming and survive seem to depend on the relation of the central density ρ (at half mass radius) of each cluster with its galactocentric distance Rgc. It is found that this relation takes the form of: The cluster systems of our Galaxy and of the two Magellanic Clouds, have been investigated. We have taken the cluster system of the conventional globulars of our Galaxy whereas the young and old systems of clusters in the LMC and SMC were treated separately. The radial distributions of central densities and half mass radii were found for all these systems showing a definite trend which depends on: (α) The total mass of the parent galaxy & (β) The age of the cluster system (young - old). It therefore appears that the total mass and/or the morphology of the parent galaxy plays a major role on the loci where clusters survive and form.

scholarly journals The physics and modes of star cluster formation: observations

2010 ◽  
Vol 368 (1913) ◽  
pp. 713-731 ◽  
Author(s):  
Charles J. Lada
Keyword(s):  
Present State ◽  
Molecular Clouds ◽  
Cluster Formation ◽  
Star Cluster ◽  
Stellar Clusters ◽  
Empirical Knowledge ◽  
Physical Processes ◽  
Subsequent Evolution ◽  
Cluster Systems ◽  
Infrared Wavelengths

Stellar clusters are born in cold and dusty molecular clouds and the youngest clusters are embedded to various degrees in a dusty dark molecular material. Such embedded clusters can be considered protocluster systems. The most deeply buried examples are so heavily obscured by dust that they are only visible at infrared wavelengths. These embedded protoclusters constitute the nearest laboratories for a direct astronomical investigation of the physical processes of cluster formation and early evolution. I review the present state of empirical knowledge concerning embedded-cluster systems and discuss the implications for understanding their formation and subsequent evolution to produce bound stellar clusters.

scholarly journals From Young to Old: Spectral Models for Star Cluster Systems

2005 ◽  
Vol 13 ◽  
pp. 187-188
Author(s):  
Uta Fritze – v. Alvensleben ◽  
Peter Anders ◽  
Richard de Grijs
Keyword(s):  
Time Evolution ◽  
Globular Cluster ◽  
Milky Way ◽  
Star Clusters ◽  
Star Cluster ◽  
Cluster Systems ◽  
Luminosity Functions ◽  
Spectral Models ◽  
Model Star ◽  
Two Populations

AbstractEvolutionary synthesis models for star clusters of various metallicities, including gaseous emission during the lifetime of the ionizing stars, are used to model star cluster systems comprising two populations: an old metal-poor globular cluster (GC) population similar to that of the Milky Way halo, and a second GC population of arbitrary metallicity. We investigate the time evolution of color distributions and luminosity functions for the two GC populations and compare with observations of E/SO galaxies. We show that multi-passband data for GC populations give clues to the relative ages and metallicities of the two subpopulations, and help constrain formation scenarios for their parent galaxies.

scholarly journals Formation and Disruption of Globular Star Clusters

2002 ◽  
Vol 207 ◽  
pp. 566-576 ◽  
Author(s):  
S. Michael Fall ◽  
Qing Zhang
Keyword(s):  
Globular Clusters ◽  
Star Clusters ◽  
Mass Function ◽  
Star Cluster ◽  
Weak Dependence ◽  
Host Galaxies ◽  
Physical Processes ◽  
Cluster Systems ◽  
Luminosity Functions ◽  
Characteristic Mass

In the first part of this article, we review observations of the mass and luminosity functions of young and old star cluster systems. We also review some of the physical processes that may determine the characteristic mass of globular clusters and the form of their mass function. In the second part of this article, we summarize our models for the disruption of clusters and the corresponding evolution of the mass function. Much of our focus here is on understanding why the mass function of globular clusters has no more than a weak dependence on radius within their host galaxies.

scholarly journals Star clusters as building blocks for dSph galaxy formation

2009 ◽  
Vol 5 (S266) ◽  
pp. 353-356
Author(s):  
P. Assmann ◽  
M. Fellhauer ◽  
M. I. Wilkinson
Keyword(s):  
Dark Matter ◽  
Numerical Experiment ◽  
Galaxy Formation ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Building Blocks ◽  
Young Star ◽  
Star Cluster ◽  
Cluster Complexes ◽  
Young Star Clusters

AbstractWe study numerically the formation of dSph galaxies. Intense starbursts, e.g., in gas-rich environments, typically produce a few to a few hundred young star clusters within a region of just a few hundred pc. The dynamical evolution of these star clusters may explain the formation of the luminous component of dwarf spheroidal (dSph) galaxies. Here, we perform a numerical experiment to show that the evolution of star cluster complexes in dark-matter haloes can explain the formation of the luminous components of dSph galaxies.

scholarly journals Simulations of Massive Star Cluster Formation and Feedback in Turbulent Giant Molecular Clouds

2010 ◽  
Vol 6 (S270) ◽  
pp. 235-238 ◽  
Author(s):  
Elizabeth Harper-Clark ◽  
Norman Murray
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Cluster Formation ◽  
Star Clusters ◽  
Star Cluster ◽  
Giant Molecular Clouds

AbstractUsing the AMR code ENZO we are simulating the formation of massive star clusters within turbulent Giant Molecular Clouds (GMCs). Here we discuss the simulations from the first stages of building realistic turbulent GMCs, to accurate star formation, and ultimately comprehensive feedback. These simulations aim to build a better understanding of how stars affect GMCs, helping to answer the questions of how long GMCs live and why only a small fraction of the GMC gas becomes stars.

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