scholarly journals Monte Carlo simulations of multiple populations in globular clusters: constraints on the cooling flow versus accretion scenario using million bodies simulations

2021 ◽  
Vol 502 (2) ◽  
pp. 1974-1989
Author(s):  
A Sollima
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Globular Clusters ◽  
Mixing Time ◽  
Stellar System ◽  
Low Mass Stars ◽  
Multiple Populations ◽  
Cooling Flow ◽  
Radial Segregation ◽  
Set Up

ABSTRACT I simulate the evolution of a stellar system hosting two stellar populations whose initial set-up is defined according to the two main scenarios proposed for the origin of multiple populations in Galactic globular clusters: (i) formation of a second generation from a cooling flow of pristine+polluted gas and (ii) accretion of polluted gas on to the proto-stellar discs of a fraction of low-mass stars. For this purpose, Monte Carlo simulations containing from 105 up to 3 × 106 particles have been run including the effect of stellar evolution, binary interactions, external tidal field, and a detailed modelling of the proto-stellar disc structure. The early accretion of gas on to proto-stellar discs is unable to produce discrete populations and to alter the chemical composition of a significant ($\gt 10{{\ \rm per\ cent}}$) fraction of stars unless a disc lifetime larger (tdisc ∼ 20 Myr) than that predicted by models is assumed. Moreover, in this scenario the mixing time-scale of the two populations is too short to reproduce the observed segregation of the chemically enriched population. On the other hand, simulations run within the cooling flow scenario can evolve after a Hubble time into stellar systems with a first-to-second population mass ratio similar to that observed in globular clusters, provided that an initial filling-factor rh/rJ > 0.15 is adopted. However, in the weak tidal field regime a radial segregation of the second population stronger than what observed in Milky Way globular clusters at large Galactocentric distances is predicted. This discrepancy disappears in simulations following eccentric orbits in a realistic axisymmetric potential.

scholarly journals Monte Carlo Simulations of Star Clusters with Primordial Binaries. Comparison with N-body Simulations and Observations

2007 ◽  
Vol 3 (S246) ◽  
pp. 99-103
Author(s):  
Mirek Giersz ◽  
Douglas C. Heggie
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Globular Clusters ◽  
Large Scale ◽  
Open Cluster ◽  
Star Clusters ◽  
Monte Carlo Code ◽  
Large Scale Simulations ◽  
Free Code

AbstractWe outline the steps needed in to calibrate the Monte Carlo code in order to perform large scale simulations of real globular clusters. We calibrate the results against N-body simulations for N = 2500, 10000 and for the old open cluster M67. The calibration is done by choosing appropriate free code parameters.

The influence of the IMRT QA set-up error on the 2D and 3D gamma evaluation method as obtained by using Monte Carlo simulations

2015 ◽  
Vol 67 (10) ◽  
pp. 1859-1867 ◽  
Author(s):  
Kyeong-Hyeon Kim ◽  
Dong-Su Kim ◽  
Tae-Ho Kim ◽  
Seong-Hee Kang ◽  
Min-Seok Cho ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Evaluation Method ◽  
Imrt Qa ◽  
Gamma Evaluation ◽  
Set Up ◽  
2D And 3D

scholarly journals The Imprints of IMBHs on the Structure of Globular Clusters: Monte-Carlo Simulations

2007 ◽  
Vol 3 (S246) ◽  
pp. 351-355 ◽  
Author(s):  
Stefan Umbreit ◽  
John M. Fregeau ◽  
Frederic A. Rasio
Keyword(s):  
Monte Carlo ◽  
Black Hole ◽  
Mass Spectrum ◽  
Monte Carlo Simulations ◽  
Stellar Evolution ◽  
Globular Clusters ◽  
Three Dimensional ◽  
Central Black Hole ◽  
The Core ◽  
First Results

AbstractWe present the first results of a series of Monte-Carlo simulations investigating the imprints of a central black hole on the core structure of globular clusters. We investigate the three-dimensional and the projected density profile of the inner regions of idealized as well as more realistic globular cluster models, taking into account a stellar mass spectrum, stellar evolution and allowing for a larger, more realistic, number of stars than was previously possible with direct N-body methods. We compare our results to other N-body simulations published previously in the literature.

scholarly journals Massive star archeology in globular clusters

2014 ◽  
Vol 9 (S307) ◽  
pp. 96-97
Author(s):  
W. Chantereau ◽  
C. Charbonnel ◽  
G. Meynet
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Massive Star ◽  
Massive Stars ◽  
Hot Stars ◽  
Low Mass Stars ◽  
Multiple Populations ◽  
Long Time ◽  
Low Mass ◽  
The Universe

AbstractGlobular clusters are among the oldest structures in the Universe and they host today low-mass stars and no gas. However, there has been a time when they formed as gaseous objects hosting a large number of short-lived, massive stars. Many details on this early epoch have been depicted recently through unprecedented dissection of low-mass globular cluster stars via spectroscopy and photometry. In particular, multiple populations have been identified, which bear the nucleosynthetic fingerprints of the massive hot stars disappeared a long time ago. Here we discuss how massive star archeology can be done through the lense of these multiple populations.

Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM

1996 ◽  
Vol 54 ◽  
pp. 478-479
Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter
Keyword(s):  
Monte Carlo ◽  
Quantitative Analysis ◽  
Monte Carlo Simulations ◽  
Cross Section ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Magnesium Ferrite ◽  
X Ray ◽  
Interaction Volume ◽  
Ferrite Spinel

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

MONTE CARLO SIMULATIONS OF ELECTRON DRIFT VELOCITIES IN THE NOBLE GASES AND THEIR MIXTURES

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-63-C7-64
Author(s):  
A. J. Davies ◽  
J. Dutton ◽  
C. J. Evans ◽  
A. Goodings ◽  
P.K. Stewart
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Noble Gases ◽  
Electron Drift
Sign in / Sign up

Export Citation Format

Share Document