Mass segregation

About: Mass segregation is a research topic. Over the lifetime, 1024 publications have been published within this topic receiving 57729 citations.

The Harlow-Shapley Symposium on Globular Cluster Systems in Galaxies : Proceedings of the 126th Symposium of the International Astronomical Union, Held in Cambridge, Massachusetts, U.S.A., August 25-29, 1986

Abstract: I Review Papers on Harlow Shapley.- Shapley's Debate.- Shapley's Era.- Shapley's Impact.- II Review Papers on Globular Clusters in the Milky Way.- An Overview of the Globular Cluster System of the Galaxy.- Kinematics of the Galactic Globular Cluster System.- Globular Cluster Color-Magnitude Diagrams.- The Overall Abundances of Globular Clusters.- The Chemical Inhomogeneity within Globular Clusters.- Ages of the Galactic Globular Clusters.- Globular Cluster Luminosity Functions.- Globular Clusters and Field Halo Stars.- III: Review Papers on Globular Clusters in Nearby Galaxies.- Old Globular Clusters in the Magellanic Clouds.- Intermediate-Age Magellanic Cloud Globular Clusters.- M 31 Cluster System.- The Clusters of M 33.- The NGC 5128 Cluster System.- Dwarf Spheroidal Galaxies and Globular Clusters.- An Overview of Globular Systems in Distant Galaxies.- The M 87 Globular Cluster System.- IV Review Papers on Evolution of Globular Clusters.- The Evolution of the System of Globular Clusters.- Tidal Heating of Globular Clusters.- Cluster Swapping.- Galaxy Formation and Cluster Formation.- The Origin of Globular Clusters.- Surface Photometry of Globular Clusters.- X-Ray Binaries and Cluster Evolution.- Precollapse Evolution of Globular Clusters.- After Core Collapse, What?.- Disolution of Star Clusters in Galaxies.- V Review Papers on Globular Clusters as Tracers and HST.- Interstellar Matter in Globular Clusters.- Globular Clusters as Tracers of the Galaxy Mass Distribution.- Globular Clusters and Primordial Composition.- Stellar Evolution in Globular Clusters and HST.- Simulations of HST Observations of Globular Clusters.- VI Review Papers Summary.- Globular Cluster Systems in Galaxies: Main Trends and Future Directions.- VII Poster Papers on Harlow Shapley and Globular Clusters in the Milky Way.- Harlow Shapley: A View from the Harvard Archives.- Harlow Shapley and the University of Missouri.- Harlow Shapley and Red Giant Stars.- The Development of a Red-Giant Branch in Low to Intermediate Mass Stars.- New Main-Sequence Luminosity Functions for Globular Clusters.- Global Versus Local Mass Functions.- A New Survey of Globular Cluster Structural and Luminosity Parameters.- Axial Ratios and Orientations for 100 Galactic Globular Star Clusters.- Abundances in Stars in Globular Clusters from Palomar Ccd Spectra.- The Metal Abundance of Metal-Rich Globular Clusters.- The Composition of Warm Giants in M 71 and M 5.- The Integrated Spectra of Metal-Rich Galactic Globular Clusters: A Two-Parameter Family.- IUE Investigations at the Core of M 79.- One-Micron Photometry of Omega Centauri Giants.- On the Bimodal Distributions of Horizontal Branches.- Bimodal Distributions on the Horizontal Branch.- Horizontal-Branch Stars with Strong He Lines.- Spectra of BHB Stars in M 3, M 13 and M 92.- Four-Color Measures of BHB Stars in M 4, M 13 and M 55.- Globular Clusters in the Vilnius Photometric System.- The Metallicity Distribution Function of Halo Dwarfs and Globular Clusters.- The Similarity of the Halo Field K Giant Population with the Globular Cluster System of Our Galaxy.- Apparent Rotation of the Galactic Globular Cluster System.- Astrometric Distances of Globular Clusters.- Absolute Proper Motions and Space Motions of Globular Clusters.- A Search for Obscured Globular Clusters.- On the Color Excesses of Globular Clusters.- First Poster Paper Discussion.- VIII Poster Papers on Cluster Systems in Nearby Galaxies.- A Search for Globular Cluster Candidates in NGC 2403.- Search for Globular Clusters in the Nearby Galaxies II. NGC 3109.- A Complete Sample of Globular Clusters in NGC 5128.- Astronomical Catalogues in the M 31 Region.- The Blue Star Clusters of M 31.- Spatial Distribution of Globular Clusters in M 31.- Formation of Populous Clusters from Metal-Poor Gas in the Magellanic Clouds.- The Development of the Red Giant Branch in Magellanic Cloud Clusters: Progress Report.- The Age Distribution and Age-Metallicity Relation of Star Clusters in a Northern Region of the LMC.- Photometric Models for Globular Clusters From Population Synthesis.- Bvri Photometry of Star Clusters in the Bok Region of the Large Magellanic Cloud.- Ages and Metal Abundances of Star Clusters in the Magellanic Clouds.- Internal Dynamics of Magellanic Cloud Clusters.- Do Binary Clusters Exist in the Large Magellanic Cloud?.- Ellipticities of Globular Clusters in the Andromeda Galaxy.- Observed Variations in the Density Profiles of Star Clusters in the LMC.- Ratio of Early to Late Type Stars in SMC Clusters.- The SMC Cluster Lindsay 11.- Abundances of Young LMC Clusters.- The Abundance of the LMC Globular Cluster NGC 2213.- Deep Photometry of the Draco Dwarf Spheroidal Galaxy.- CCD Photometry in the Core of the Fornax Dwarf Galaxy.- A Candidate for the Recovered Nova of 1938 in the Globular Cluster M 14.- The Absolute Luminosity of RR Lyrae Variables.- The Distances to RR Lyrae Variables.- Double-Mode RR Lyrae Stars in IC 4499.- Short-Period Variables in Globular Clusters of Moderate Metallicity.- Second Poster Paper Discussion.- IX: Poster Papers on Cluster Systems in Distant Galaxies. Deep Photometry and CM Diagrams.- The Nuclei of Nucleated Dwarf Elliptical Galaxies - Are they Globular Clusters?.- The Globular Cluster System of M 87.- The Core of the M 87 Globular Cluster System.- U Photometry of Globular Clusters in the Central Region of M 87.- Globular Clusters Detected uin the Coma Cluster'S Central Giant Galaxy NGC 4874.- Globular Clusters in Different Types of Spiral Galaxies.- Globular Clusters in Lenticular Galaxies: NCG 3115.- Globular Clusters as Extragalactic Distance Indicators: Maximum Likelihood Methods.- Photometry of Faint Stars in Globular Clusters Using the Six Meter Telescope.- High Precision Photometry of 10,000 Stars in M 3.- Deep CCD Photometry in M 5.- Photographic Photometry of 4500 Stars in M 30.- An Automated HR Diagram for NGC 6809 (M 55).- Deep CCD Photometry in Omega Centauri and NGC 3201.- Deep CCD Photometry of OMEGA Centauri.- The Ages of Globular Clusters Derived from BVRI CCD Photometry.- Turnoffs and Ages of Globular Clusters.- The Dynamics of Globular Clusters in High Eccentricity Orbits.- Mass Distributions of Galaxies with Globular Cluster Systems.- The Dynamics of Globular Cluster Systems.- Third Poster Paper Discussion.- X Poster Papers on Formation and Evolution of Globular Clusters.- A Multicolor CCD Survey of Southern Globular Clusters.- The Structure of Collapsed Cluster Cores.- Radial Velocity Study of NGC 6712.- A Survey of Globular Cluster Velocity Dispersions.- Anistropy in OMEGA Centauri and 47 Tucanae.- Evolution of Globular Clusters Including a Degenerate Component.- Evolution of Globular Clusters with Tidally-Captured Binaries Through Core Collapse.- Binary Interactions in Star Clusters.- Tidal Effects on Stellar Evolution in Close Binaries Formed in Globular Clusters.- The Effects of Stellar Evolution and Galactic Tides on Globular Cluster Evolution.- The Spatial Distribution of Spectroscopic Binaries and Blue Stragglers in M 67.- Evidence for Mass Segregation in NGC 5466.- Origin and Radial Distribution of Faint Blue Horizontal-Branch Stars.- Variability of Omega Centauri Blue Stragglers: Clues to their Origin.- A Search for Optical Counterparts of Globular Cluster X-Ray Sources.- Low Luminosity Globular Cluster X-Ray Sources.- Exosat Observations of Omega Centauri.- New Methods for the Search for Hot Gas in Globular Clusters.- Radial Velocity Profiles for Anisotropic Spherically Symmetric Clusters: An Example.- Linear Density Waves in Globular Clusters.- On Gravothermal Oscillations.- Cooling and Fragmentation of Proto-Globular Cluster Clouds.- Formation of Globular Clusters and the First Stellar Generation.- Formation of Population III Objects Due to Cosmic Strings.- Fourth Poster Paper Discussion.- Random Quotes.- Name Index.- Object Index.- Addresses Of Participants.

No Evidence of Mass Segregation in the Low-mass Galactic Globular Cluster NGC 6101

Abstract: We used a combination of Hubble Space Telescope and ground-based data to probe the dynamical state of the low-mass Galactic globular cluster NGC 6101. We have rederived the structural parameters of the cluster by using star counts and we find that it is about three times more extended than thought before. By using three different indicators, namely the radial distribution of blue straggler stars (BSSs), that of main-sequence binaries, and the luminosity (mass) function, we demonstrated that NGC 6101 shows no evidence of mass segregation, even in the innermost regions. Indeed, both the BSS and the binary radial distributions fully resemble those of any other cluster population. In addition, the slope of the luminosity (mass) function does not change with the distance, as expected for non-relaxed stellar systems. NGC 6101 is one of the few globulars where the absence of mass segregation has been observed so far. This result provides additional support for the use of the “dynamical clock” calibrated on the radial distribution of the blue stragglers as a powerful indicator of the cluster dynamical age. Based on observations collected at the the Very Large Telescope of the European Southern Observatory, Cerro Paranal, Chile (under proposal 091.D-0562). Also based on observations with the NASA/ESA HST (Prop. 10775), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555.

CHARACTERIZATION OF THE PRAESEPE STAR CLUSTER BY PHOTOMETRY AND PROPER MOTIONS WITH 2MASS, PPMXL, AND Pan-STARRS

Abstract: Membership identification is the first step in determining the properties of a star cluster. Low-mass members in particular could be used to trace the dynamical history, such as mass segregation, stellar evaporation, or tidal stripping, of a star cluster in its Galactic environment. We identified member candidates of the intermediate-age Praesepe cluster (M44) with stellar masses ~0.11-2.4 M ☉, using Panoramic Survey Telescope And Rapid Response System and Two Micron All Sky Survey photometry, and PPMXL proper motions. Within a sky area of 3° radius, 1040 candidates are identified, of which 96 are new inclusions. Using the same set of selection criteria on field stars, an estimated false positive rate of 16% was determined, suggesting that 872 of the candidates are true members. This most complete and reliable membership list allows us to favor the BT-Settl model over other stellar models. The cluster shows a distinct binary track above the main sequence, with a binary frequency of 20%-40%, and a high occurrence rate of similar mass pairs. The mass function is consistent with that of the disk population but shows a deficit of members below 0.3 solar masses. A clear mass segregation is evidenced, with the lowest-mass members in our sample being evaporated from this disintegrating cluster.

The dynamical state of the globular cluster m10 (ngc 6254)

Abstract: Studying the radial variation of the stellar mass function (MF) in globular clusters (GCs) has proved a valuable tool to explore the collisional dynamics leading to mass segregation and core collapse. Recently, Pasquato et al. (2009) used the mass segregation profile to investigate the presence of an intermediate-mass black hole (IMBH) in NGC?2298. As a relaxed cluster with a large core, M10 (NGC?6254) is suitable for a similar investigation. In order to study the radial dependence of the luminosity and MF of M10, we used deep high resolution archival images obtained with the Advanced Camera for Survey (ACS) on board the Hubble Space Telescope, reaching out to approximately the cluster's half-mass radius (r hm), combined with deep Wide Field and Planetary Camera 2 (WFPC2) images that extend our radial coverage to more than 2 r hm. From our photometry, we derived a radial mass segregation profile and a global MF that we compared with those of simulated clusters containing different energy sources (namely hard binaries and/or an IMBH) able to halt core collapse and to quench mass segregation. A set of direct N-body simulations of GCs, with and without an IMBH of mass 1% of the total cluster mass, comprising different initial mass functions and primordial binary fractions, was used to predict the observed mass segregation profile and MF. The mass segregation profile of M10 is not compatible with cluster models without either an IMBH or primordial binaries, as a source of energy appears to be moderately quenching mass segregation in the cluster. Unfortunately, the present observational uncertainty on the binary fraction in M10 does not allow us to confirm the presence of an IMBH in the cluster, since an IMBH, a dynamically non-negligible binary fraction (~5%), or both can equally well explain the radial dependence of the cluster MF.

Mass segregation in the young open cluster NGC 2547

Abstract: We present a study of mass segregation of the young (20-35 Myr isochronal age) open cluster NGC 2547. We find good evidence that mass segregation exists in NGC 2547 down to 3 M O ., and weak evidence for mass segregationdown to 1 M O .. Theoretical models of an initially unsegregated model of NGC 2547 using the NBODY2 code show weaker mass segregation, implying that at least some of the observed mass segregation has a primordial origin. We also report the discovery of three possible escaped cluster members, which share the proper motion and colours of the cluster, but lie nearly a degree from the cluster centre.