Topic
Mass segregation
About: Mass segregation is a research topic. Over the lifetime, 1024 publications have been published within this topic receiving 57729 citations.
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TL;DR: In this paper, it was shown that rich star clusters take at least several local dynamical times to form, and so are quasi-equilibrium structures during their assembly, and that these long formation timescales are consistent with the expected star formation rate in turbulent gas.
Abstract: We argue that rich star clusters take at least several local dynamical times to form, and so are quasi-equilibrium structures during their assembly. Observations supporting this conclusion include morphologies of star-forming clumps, momentum flux of protostellar outflows from forming clusters, age spreads of stars in the Orion Nebula Cluster (ONC) and other clusters, and the age of a dynamical ejection event from the ONC. We show that these long formation timescales are consistent with the expected star formation rate in turbulent gas, as recently evaluated by Krumholz & McKee. Finally, we discuss the implications of these timescales for star formation efficiencies, the disruption of gas by stellar feedback, mass segregation of stars, and the longevity of turbulence in molecular clumps.
15 citations
TL;DR: In this article, the authors present high-quality Washington CT1 and Johnson BVI photometry of the Haffner 9 open cluster field to clean the colour-magnitude diagrams from field star contamination, which was found a common source in previous works for discordant fundamental parameter estimates.
Abstract: We turn our attention to Haffner 9, a Milky Way open cluster whose previous fundamental parameter estimates are far from being in agreement. In order to provide with accurate estimates we present high-quality Washington CT1 and Johnson BVI photometry of the cluster field. We put particular care in statistically clean the colour-magnitude diagrams (CMDs) from field star contamination, which was found a common source in previous works for the discordant fundamental parameter estimates. The resulting cluster CMD fiducial features were confirmed from a proper motion membership analysis. Haffner 9 is a moderately young object (age ~ 350 Myr), placed in the Perseus arm -at a heliocentric distance of ~ 3.2 kpc-, with a lower limit for its present mass of ~ 160 Mo and of nearly metal solar content. The combination of the cluster structural and fundamental parameters suggest that it is in an advanced stage of internal dynamical evolution, possibly in the phase typical of those with mass segregation in their core regions. However, the cluster still keeps its mass function close to that of the Salpeter's law.
15 citations
TL;DR: In this paper, the authors present Spitzer IRAC and MIPS observations of the star-forming region containing intermediate-mass young stellar objects (YSO) AFGL 490 and construct a minimum spanning tree of their projected positions, isolating one locally over-dense cluster core containing 219 YSOs (60.8% of the region's members).
Abstract: We present Spitzer IRAC and MIPS observations of the star-forming region containing intermediate-mass young stellar object (YSO) AFGL 490. We supplement these data with near-IR 2MASS photometry and with deep SQIID observations off the central high extinction region. We have more than doubled the known membership of this region to 57 Class I and 303 Class II YSOs via the combined 1-24 um photometric catalog derived from these data. We construct and analyze the minimum spanning tree of their projected positions, isolating one locally over-dense cluster core containing 219 YSOs (60.8% of the region's members). We find this cluster core to be larger yet less dense than similarly analyzed clusters. Although the structure of this cluster core appears irregular, we demonstrate that the parsec-scale surface densities of both YSOs and gas are correlated with a power law slope of 2.8, as found for other similarly analyzed nearby molecular clouds. We also explore the mass segregation implications of AFGL 490's offset from the center of its core, finding that it has no apparent preferential central position relative to the low-mass members.
14 citations
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01 Jan 2009
TL;DR: In this paper, the authors investigated the chemical abundance and radial velocities of the Galactic Globular Clusters (GCLs) in the direction of the Inner Galaxy.
Abstract: Detailed Studies of Individual Globular Clusters.- Detailed Chemical Abundances of Extragalactic Globular Clusters.- Spectroscopic Abundances and Radial Velocities of the Galactic Globular Clusters 2MASS GC01 and 2MASS GC02: Preliminary Results.- Abundance Anomalies in Galactic Globular Clusters - Looking for the Stellar Culprits.- Globular Clusters in the Direction of the Inner Galaxy.- Globular Cluster Research with Astronomical Archives.- Super-He-Rich Populations in Globular Clusters.- Testing the BH 176 and Berkeley 29 Association with GASS/Monoceros.- New Yonsei-Yale (Y 2) Isochrones and Horizontal-Branch Evolutionary Tracks with Helium Enhancements.- Search for Candle Stars in Globular Clusters: Spectroscopic Analysis of Post-AGB Candidates.- The Lack of Binaries Among Hot Horizontal Branch Stars: M80 and NGC5986.- Semi-Empirical Determination of the Mass Distribution of Horizontal Branch Stars in M3.- The Most Massive Clusters.- Globular Clusters, Galactic Nuclei and Supermassive Black Holes.- UCDs - A Mixed Bag of Objects.- Ultra-Compact Dwarf Galaxies and Globular Clusters: A Review of Their Spatial and Dynamical Properties.- The Maximum Mass of Star Clusters.- The Stellar Population of Ultra-Compact Dwarf Galaxies.- News on Ultra-Compact Dwarfs and Blue Globular Clusters.- UCDs and GCs: Structural Differences from HST Imaging.- Ultra-Compact Stellar Systems in the Fornax Galaxy Cluster.- Multi-Colour Imaging of Ultra-Compact Objects in the Fornax Cluster.- Young Star Clusters.- Hierarchical Formation of Galactic Clusters.- Young Massive Clusters - Formation Efficiencies and (Initial) Mass Functions.- The Radii of Thousands of Star Clusters in M51 with HST/ACS.- Extragalactic Star Clusters in Merging Galaxies.- The Environment of Young Massive Clusters.- Star/Cluster Formation in Complexes: Insights from IFUs and HST.- Spectral Evolution of Blue Concentrated Star Clusters in the Large Magellanic Cloud.- Young Star Clusters in the SMC.- Molecular Clouds and Star Formation in the Magellanic System by NANTEN.- Two Star Cluster Populations in NGC 45.- Characterization of Open Cluster Remnants.- HST Photometry of the Binary Globular Cluster Sersic 13N-S in NGC5128[1].- Globular Cluster Systems in Dwarf and Irregular Galaxies.- LMC Cluster Abundances and Kinematics.- Globular Clusters in Dwarf Galaxies.- Globular Clusters in Dwarf and Giant Galaxies.- The Age-Metallicity Relation of the SMC.- Integrated Spectroscopic Analysis of Galactic and Small Magellanic Cloud Clusters.- Variable Stars in the Globular Clusters and in the Field of the Fornax dSph Galaxy.- Physical Parameters of Intermediate-Age LMC Clusters from Modelling of HST CMDs.- RGB Properties of the LMC/SMC Clusters in the Infrared.- WLM-1: A Non-Rotating, Gravitationally Unperturbed, Highly Elliptical Extragalactic Globular Cluster.- Globular Cluster Systems in Spiral Galaxies.- Star Clusters in M33 - Clues to Galaxy Formation and Evolution.- M31 and its Globular Clusters.- IR Integrated Light Colors For Galactic GCs and An Update on Young M31 Globular Clusters.- Nuclear Star Clusters in Edge-on Galaxies.- HST ACS Wide-Field Photometry of the Sombrero Galaxy Globular Cluster System.- Intermediate-Age Globular Clusters in M31.- Metal-Poor Globular Clusters of the Galactic Bulge.- Globular Cluster System and Milky Way Properties Revisited.- RR Lyrae-Based Calibration of the Globular Cluster Luminosity Function.- Globular Cluster Systems in Spiral Galaxies Using ACS Imaging.- Laser Guide Star Imaging of M31 Globulars.- GALEX UV Observations of M31 Globular Clusters.- Integrated Spectroscopy of Galactic Globular Clusters.- Globular Cluster Systems in Early-Type Galaxies.- Globular Cluster Systems: Do They Really Trace Star Formation? (Or Rather: What Mode of Star Formation Do They Trace?).- Globular Clusters in Early Type Galaxies.- Globular Clusters and Galaxy Formation.- Globular Cluster Systems in Giant Ellipticals: New and Old Patterns.- The ACS Virgo Cluster Survey.- Globular Clusters at the Centre of the Fornax Cluster: Tracing Interactions Between Galaxies.- Globular Cluster Bimodality Revisited (and the Globulars-Galaxy Halo Connection).- Globular Cluster Systems, Diffuse Star Clusters, and Host Galaxies in the ACS Virgo Cluster Survey.- Hot Populations in M87 Globular Clusters.- A Subaru/Suprime-Cam Wide-Field Survey of Globular Cluster Populations around M87.- Stellar Populations of Globular Clusters in NGC 1407.- The Globular Cluster System of NGC 5846 Revisited: Colours, Sizes and X-Ray Counterparts.- Globular Cluster Systems in Shell Ellipticals.- GMOS Photometry of Five Globular Cluster Systems: NGC 4649, NGC 3923, NGC 524, NGC 3115 and NGC 3379.- Structural Parameters from Ground-based Observations of Globular Clusters in NGC 5128.- Globular Cluster Populations in Early-Type Galaxies.- The Low-Mass X-Ray Binary Globular Cluster Connection in the ACS Virgo Cluster Survey.- The Globular Cluster System of NGC 5128: Combining Broad-Band Color and Lick Index Analysis.- The Galaxy - Globular Cluster Connection in NGC 3115.- Velocity Dispersions of Bright Globular Clusters in NGC 5128.- Evolution of Cluster Systems and their Host Galaxies.- Imprint of Galaxy Formation and Evolution on Globular Cluster Properties.- Formation of Globular Clusters in Hierarchical Cosmology: ART and Science.- Globular Cluster Formation in Mergers.- The Formation Histories of Metal-Rich and Metal-Poor Globular Clusters.- Globular Cluster System Evolution in Early Type Galaxies.- Star Cluster Evolution: From Young Massive Star Clusters to Old Globulars.- A Wide-Field Survey of the Globular Cluster Systems of Giant Galaxies.- IGCs in the Virgo Cluster.- A New Explanation of Globular Cluster Color Distributions.- Formation of Intracluster and Intercluster Globular Clusters.- The Effect of Giant Molecular Clouds on Star Clusters.- Metal-rich Globular Clusters: An Unaccounted Factor Responsible for Their Formation?.- On the Globular Cluster Color Distributions.- Dynamical Evolution of Star Clusters.- Dissolution of Globular Clusters.- Dynamical Masses of Young Star Clusters: Constraints on the Stellar IMF and Star-Formation Efficiency.- Dynamical Evolution of Rotating Globular Clusters with Embedded Black Holes.- The Dynamical Evolution of Young Clusters and Galactic Implications.- Simulations of Globular Clusters Merging in Galactic Nuclear Regions.- The Origin of the Gaussian Initial Mass Function of Globular Cluster Systems.- Evolution of Globular Cluster Systems.- Tidal Disruption and the Tale of Three Clusters.- Tidal Tails Around Globular Clusters: Are they Good Tracers of Cluster Orbits?.- Modelling the Tidal Tails of NGC 5466.- The Search for Tidal Tails of Globular Clusters: NGC4147.- Internal Rotation of Young Globular Clusters.- Mass Segregation in Young Star Clusters.- Dynamics of Globular Cluster Systems.- Kinematics of Globular Cluster Systems.- Dark Matter in the Elliptical Galaxies NGC 1399 and NGC 4636.- Ages, Abundances, and Kinematics of Globular Clusters in NGC 3379 and NGC 4649 with Gemini/GMOS.- The Dark Halo of NGC 1399 and MOND.- Dynamics of the Globular Cluster System of NGC 5128.- Open Questions in the Globular Cluster - Galaxy Connection.- Open Questions in the Globular Cluster - Galaxy Connection.
14 citations
TL;DR: In this article, the authors presented CCD multicolor photometry for the old open cluster NGC 188 using 15 intermediate-band filters covering 3000?10000? observations, which were carried out as part of the Beijing?Arizona?Taiwan?Connecticut Multicolor Sky Survey.
Abstract: This paper presents CCD multicolor photometry for the old open cluster NGC 188. The observations were carried out as part of the Beijing?Arizona?Taiwan?Connecticut Multicolor Sky Survey from 1995 February to 2008 March, using 15 intermediate-band filters covering 3000?10000 ?. By fitting the Padova theoretical isochrones to our data, the fundamental parameters of this cluster are derived: an age of Gyr, a distance modulus of , and a reddening of . The radial surface density profile of NGC 188 is obtained using the star count. By fitting the King model, the structural parameters of NGC 188 are derived: a core radius of , a tidal radius of , and a concentration parameter of . Fitting the mass function (MF) to a power-law function , the slopes of the MFs for different spatial regions are derived. We find that NGC 188 presents a slope break in the MF. The break mass is . In the mass range above , the slope of the overall region is . The slope of the core region is , and the slopes of the external regions are and , respectively. In the mass range below , these slopes are , , , and , respectively. The mass segregation in NGC 188 is reflected in the obvious variation of the slopes in different spatial regions of this cluster.
14 citations