scholarly journals Effects of Stellar-Mass Black Holes on Massive Star Cluster Evolution

2015 ◽  
Vol 12 (S316) ◽  
pp. 234-239
Author(s):  
Sourav Chatterjee ◽  
Meagan Morscher ◽  
Carl L. Rodriguez ◽  
Bharat Pattabiraman ◽  
Frederic A. Rasio

AbstractRecent observations have revealed the existence of stellar mass black hole (BH) candidates in some globular clusters (GC) in the Milky Way and in other galaxies. Given that the detection of BHs is challenging, these detections likely indicate the existence of large populations of BHs in these clusters. This is in direct contrast to the past understanding that at most a handful of BHs may remain in old GCs due to quick mass segregation and rapid mutual dynamical ejection. Modern realistic star-by-star numerical simulations suggest that the retention fraction of BHs is typically much higher than what was previously thought. The BH dynamics near the cluster center leads to dynamical formation of new binaries and dynamical ejections, and acts as a persistent and significant energy source for these clusters. We have started exploring effects of BHs on the global evolution and survival of star clusters. We find that the evolution as well as survival of massive star clusters can critically depend on the details of the initial assumptions related to BH formation physics, such as natal kick distribution, and the initial stellar mass function (IMF). In this article we will present our latest results.

1992 ◽  
Vol 45 (4) ◽  
pp. 407
Author(s):  
KC Freeman

The young globular star clusters in the LMC offer us insights into the formation and early dynamical evolution of globular clusters which are unobtainable from the old globular clusters in our Galaxy. Because these young clusters are so young and populous, they provide an opportunity to measure the upper end of the initial mass function by direct means and also through the dynamical effects of stellar mass loss on the structure of the clusters.


2009 ◽  
Vol 5 (S266) ◽  
pp. 49-57 ◽  
Author(s):  
Richard de Grijs

AbstractIn spite of significant recent and ongoing research efforts, most of the early evolution and long-term fate of young massive star clusters remain clouded in uncertainties. Here, I discuss our understanding of the initial conditions of star cluster formation and the importance of initial substructure for the subsequent dynamical-evolution and mass-segregation timescales. I also assess our current understanding of the (initial) binary fraction in star clusters and the shape of the stellar initial mass function at the low-mass end in the low-metallicity environment of the Large Magellanic Cloud. Finally, I question the validity of our assumptions leading to dynamical cluster mass estimates. I conclude that it seems imperative that observers, modellers and theorists combine efforts and exchange ideas and data freely for the field to make a major leap forward.


2019 ◽  
Vol 14 (S351) ◽  
pp. 346-349
Author(s):  
Enrico Vesperini ◽  
Jongsuk Hong ◽  
Jeremy J. Webb ◽  
Franca D’Antona ◽  
Annibale D’Ercole

AbstractWe present a brief summary of the results of a study of the effects of dynamical evolution on the stellar mass function of multiple-population globular clusters. Theoretical studies have predicted that the process of multiple-population cluster formation results in a system in which second-generation (2G) stars are initially more centrally concentrated than first-generation (1G) stars. In the study presented here, we have explored the implications of the initial differences between the 2G and 1G structural properties for the evolution of the local (measured at different distances from a cluster center) and global mass function. We have studied both systems in which 1G and 2G stars start with the same initial mass function (IMF) and systems in which 1G and 2G stars have different IMFs. Finally we have explored the evolution of the spatial mixing and found that the multiscale nature of the clusters studied leads to a dependence of the mixing rate on the stellar mass.


1999 ◽  
Vol 190 ◽  
pp. 460-461 ◽  
Author(s):  
S. F. Beaulieu ◽  
R. Elson ◽  
G. Gilmore ◽  
R. A. Johnson ◽  
N. Tanvir ◽  
...  

We present details of the database from a large Cycle 7 HST project to study the formation and evolution of rich star clusters in the LMC (see Elson et al., this volume). Our data set, which includes NICMOS, WFPC2 and STIS images of 8 clusters, will enable us to derive deep luminosity functions for the clusters and to investigate the universality of the stellar IMF. We will look for age spreads in the youngest clusters, quantify the population of binary stars in the cores of the clusters and at the half-mass radii, and follow the development of mass segregation.


Author(s):  
William E. Harris

The ensemble of all star clusters in a galaxy constitutes its star cluster system . In this review, the focus of the discussion is on the ability of star clusters, particularly the systems of old massive globular clusters (GCs), to mark the early evolutionary history of galaxies. I review current themes and key findings in GC research, and highlight some of the outstanding questions that are emerging from recent work.


2002 ◽  
Vol 207 ◽  
pp. 687-690
Author(s):  
Marco Sirianni ◽  
Antonella Nota ◽  
Guido De Marchi ◽  
Claus Leitherer ◽  
Mark Clampin

We present a new study of the low end of the stellar IMF of NGC 330, the richest young star cluster in the Small Magellanic Cloud (SMC). Using deep broadband images taken with the HST/WFPC2 we have derived the cluster's luminosity function and constructed the initial mass function (IMF) in the mass range 1 − 7M⊙. We have investigated the IMF as a function of the radial distance from the cluster center. We find that, after correction for background contamination, the IMF is fairly homogeneous with a slope slightly steeper than Salpeter's in the central regions of the cluster (< 40″) but becomes increasingly steeper with distance, indicating a preponderance of massive stars in the core of the cluster. NGC 330 is one of the first clusters for which evidence of mass segregation is directly found.


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