scholarly journals Young Star Clusters in the LMC

1992 ◽  
Vol 45 (4) ◽  
pp. 407
Author(s):  
KC Freeman
Keyword(s):  
Mass Loss ◽  
Globular Clusters ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Young Star ◽  
Stellar Mass ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Young Star Clusters

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.

scholarly journals The Mass Function of Young Star Clusters in our Galaxy and Nearby Galaxies: Is It Universal?

2002 ◽  
Vol 207 ◽  
pp. 515-524
Author(s):  
Ram Sagar
Keyword(s):  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Young Star ◽  
Initial Mass Function ◽  
Galactocentric Distance ◽  
Photometric Observations ◽  
Nearby Galaxies ◽  
Mass Segregation ◽  
Young Star Clusters

Mass functions (MFs) derived from photometric observations of young star clusters of our Galaxy, the Magellanic Clouds (MCs), M31 and M33 have been used to investigate the question of universality of the initial mass function and presence of mass segregation in these systems. Observational determination of the MF slope of young star clusters have an inherent uncertainty of at least ∼ 1.0 dex in the Milky Way and of ∼ 0.4 dex in the MCs. There is no obvious dependence of the MF slope on either galactocentric distance or age of the young star clusters or on the spatial concentration of the stars formed or on the galactic characteristics including metallicity. Effects of mass segregation have been observed in a good number of young stellar groups of our Galaxy and MCs. As their ages are much smaller than their dynamical evolution times, star formation processes seem to be responsible for the observed mass segregation in them.

scholarly journals The Initial Mass Function in Young Star Clusters

1986 ◽  
Vol 7 ◽  
pp. 489-499
Author(s):  
Hans Zinnecker
Keyword(s):  
Star Formation ◽  
Recent Work ◽  
Star Clusters ◽  
Mass Function ◽  
Young Star ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Stellar Content ◽  
Young Star Clusters ◽  
The Imf

AbstractThis review discusses both the earlier and the most recent work on the IMF in young star clusters. It is argued that the study of the stellar content of young star clusters offers the best chance of developing a theory of star formation and of the IMF.

scholarly journals Young star clusters in the LMC

1991 ◽  
Vol 148 ◽  
pp. 177-181
Author(s):  
K. C. Freeman ◽  
R.A.W. Elson
Keyword(s):  
Globular Clusters ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Large Magellanic Cloud ◽  
Young Star ◽  
Magellanic Cloud ◽  
Initial Mass ◽  
Young Star Clusters ◽  
Mass Functions

We discuss the integrated colours, kinematics, formation, dynamical evolution and initial mass functions of the young globular star clusters in the Large Magellanic Cloud (LMC). Because these clusters are so young, they offer us insights, unobtainable from the old globular clusters in our Galaxy, into the formation and early dynamical evolution of globular clusters.

scholarly journals MOCCA-SURVEY Database I: Dissolution of tidally filling star clusters harboring black hole subsystem

2019 ◽  
Vol 14 (S351) ◽  
pp. 438-441 ◽  
Author(s):  
Mirek Giersz ◽  
Abbas Askar ◽  
Long Wang ◽  
Arkadiusz Hypki ◽  
Agostino Leveque ◽  
...  
Keyword(s):  
Black Hole ◽  
Star Clusters ◽  
Mass Function ◽  
Stellar Mass ◽  
Star Cluster ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Dissolution Process ◽  
Dissolution Mechanism ◽  
Dynamical Equilibrium

AbstractWe investigate the dissolution process of star clusters embedded in an external tidal field and harboring a subsystem of stellar-mass black hole. For this purpose we analyzed the MOCCA models of real star clusters contained in the Mocca Survey Database I. We showed that the presence of a stellar-mass black hole subsystem in tidally filling star cluster can lead to abrupt cluster dissolution connected with the loss of cluster dynamical equilibrium. Such cluster dissolution can be regarded as a third type of cluster dissolution mechanism. We additionally argue that such a mechanism should also work for tidally under-filling clusters with a top-heavy initial mass function.

scholarly journals Stellar initial mass function variation in massive early-type galaxies: the potential role of the deuterium abundance

2020 ◽  
Vol 498 (3) ◽  
pp. 4051-4059 ◽  
Author(s):  
Timothy A Davis ◽  
Freeke van de Voort
Keyword(s):  
Mass Loss ◽  
Cosmic Time ◽  
Mass Function ◽  
Stellar Mass ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Early Type ◽  
Root Cause ◽  
Stellar Initial Mass Function ◽  
Low Mass

ABSTRACT The observed stellar initial mass function (IMF) appears to vary, becoming bottom-heavy in the centres of the most massive, metal-rich early-type galaxies. It is still unclear what physical processes might cause this IMF variation. In this paper, we demonstrate that the abundance of deuterium in the birth clouds of forming stars may be important in setting the IMF. We use models of disc accretion on to low-mass protostars to show that those forming from deuterium-poor gas are expected to have zero-age main-sequence masses significantly lower than those forming from primordial (high deuterium fraction) material. This deuterium abundance effect depends on stellar mass in our simple models, such that the resulting IMF would become bottom-heavy – as seen in observations. Stellar mass loss is entirely deuterium free and is important in fuelling star formation across cosmic time. Using the Evolution and Assembly of GaLaxies and their Environments (EAGLE) simulation we show that stellar mass-loss-induced deuterium variations are strongest in the same regions where IMF variations are observed: at the centres of the most massive, metal-rich, passive galaxies. While our analysis cannot prove that the deuterium abundance is the root cause of the observed IMF variation, it sets the stage for future theoretical and observational attempts to study this possibility.

scholarly journals On the temporal evolution of the stellar mass function of Galactic clusters

2009 ◽  
Vol 5 (S266) ◽  
pp. 81-86
Author(s):  
Guido De Marchi ◽  
Francesco Paresce ◽  
Simon Portegies Zwart
Keyword(s):  
Power Law ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Stellar Mass ◽  
Initial Mass Function ◽  
Dissolution Time ◽  
Power Law Distribution ◽  
Galactic Clusters ◽  
Characteristic Mass

AbstractWe show that we can obtain a good fit to the present-day stellar-mass functions of a large sample of young and old Galactic clusters with a tapered Salpeter power-law distribution function with an exponential truncation of the form dN/dm ∝ mα [1 − exp(−m/mc)β]. The average value of the power-law index α is ~−2.2, very close to the Salpeter value of −2.3, while the characteristic mass, mc, is in the range 0.1–0.6M⊙ and does not seem to vary in any systematic way with the present cluster parameters such as metal abundance, total cluster mass or central concentration. However, the characteristic mass shows a remarkable correlation with the dynamical age of the cluster, namely mc/M⊙ ≃ 0.15 + 0.5 × t3/4dyn, where tdyn is the dynamical time, taken as the ratio of cluster age and dissolution time. The small scatter around this correlation is likely due to uncertainties on the estimated value of tdyn. We attribute the observed trend to the onset of mass segregation through two-body relaxation in a tidal environment, causing preferential loss of low-mass stars from the cluster and hence a drift of the characteristic mass towards higher values. If dynamical evolution is indeed at the origin of the observed trend, it seems plausible that globular clusters, now with mc ≃ 0.35M⊙, were born with a stellar mass function very similar to that measured today in the youngest Galactic clusters and with a value of mc around 0.15 M⊙. This is consistent with the absence of a turn-over in the mass function of the Galactic bulge down to the observational limit at ~0.2M⊙ and argues for the universality of the initial mass function of Population I and II stars.

scholarly journals Dynamical evolution of star clusters with top-heavy IMF

2019 ◽  
Vol 14 (S351) ◽  
pp. 447-450
Author(s):  
Hosein Haghi ◽  
Ghasem Safaei ◽  
Akram H. Zonoozi ◽  
Pavel Kroupa
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Massive Stars ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Initial Mass Function ◽  
Dissolution Time ◽  
Theoretical Studies ◽  
Cloud Density

AbstractSeveral observational and theoretical studies suggest that the initial mass function (IMF) slope for massive stars in globular clusters (GCs) depends on the initial cloud density and metallicity, such that the IMF becomes increasingly top-heavy with decreasing metallicity and increasing the gas density of the forming object. Using N-body simulations of GCs starting with a top-heavy IMF and undergo early gas expulsion within a Milky Way-like potential, we show how such a cluster would evolve. By varying the degree of top-heaviness, we calculate the dissolution time and the minimum cluster mass needed for the cluster to survive after 12 Gyr of evolution.

scholarly journals Dynamical Evolution of Mass-Segregated Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 181-185
Author(s):  
Enrico Vesperini ◽  
Steve McMillan ◽  
Simon Portegies Zwart
Keyword(s):  
Mass Loss ◽  
Density Profile ◽  
Stellar Evolution ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Evolution ◽  
Stellar Initial Mass Function ◽  
Mass Segregation

AbstractWe present the results of a survey of N-body simulations aimed at exploring the implications of primordial mass segregation on the dynamical evolution of star clusters. We show that, in a mass-segregated cluster, the effect of early mass loss due to stellar evolution is, in general, more destructive than for an unsegregated cluster with the same density profile and leads to shorter lifetimes, a faster initial evolution toward less concentrated structure and flattening of the stellar initial mass function.

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