On the Effects of Subvirial Initial Conditions and the Birth Temperature of R136

Abstract

We investigate the effect of different initial virial temperatures, Q, on the dynamics of star clusters. We find that the virial temperature has a strong effect on many aspects of the resulting system, including among others: the fraction of bodies escaping from the system, the depth of the collapse of the system, and the strength of the mass segregation. These differences deem the practice of using "cold" initial conditions no longer a simple choice of convenience. The choice of initial virial temperature must be carefully considered as its impact on the remainder of the simulation can be profound. We discuss the pitfalls and aim to describe the general behavior of the collapse and the resultant system as a function of the virial temperature so that a well reasoned choice of initial virial temperature can be made. We make a correction to the previous theoretical estimate for the minimum radius, $R_{min}$, of the cluster at the deepest moment of collapse to include a Q dependency, $R_{min}\approx Q+N^{(-1/3)}$, where $N$ is the number of particles. We use our numerical results to infer more about the initial conditions of the young cluster R136. Based on our analysis, we find that R136 was likely formed with a rather cool, but not cold, initial virial temperature ($Q\approx 0.13$). Using the same analysis method, we examined 15 other young clusters and found the most common initial virial temperature to be between 0.18 and 0.25.

arXiv commentAccepted for publication in MNRAS

References in corpus (25)

• Young massive star clusters
• HOP: A New Group-Finding Algorithm for N-body Simulations
• Surface Brightness Profiles and Structural Parameters for 53 Rich Stellar Clusters in the Large Magellanic Cloud
• The VLT-FLAMES Tarantula Survey I: Introduction and observational overview
• Early Evolution of Stellar Groups and Clusters: Environmental Effects on Forming Planetary Systems
• Dynamical mass segregation on a very short timescale
• Before the first supernova: combined effects of HII regions and winds on molecular clouds
• Using the minimum spanning tree to trace mass segregation
• Performance Analysis of Direct N-Body Algorithms on Special-Purpose Supercomputers
• The early dynamical evolution of cool, clumpy star clusters
• Probing the formation of intermediate- to high-mass stars in protoclusters: A detailed millimeter study of the NGC 2264 clumps
• The distinction between star clusters and associations
• SAPPORO: A way to turn your graphics cards into a GRAPE-6
• A double cluster at the core of 30 Doradus
• The low-mass Initial Mass Function in the 30 Doradus starburst cluster
• The evolution of embedded star clusters
• The VLT-FLAMES Tarantula Survey. VII. A low velocity dispersion for the young massive cluster R136
• On the velocity dispersion of young star clusters: super-virial or binaries?
• Dynamical Evolution of Young Embedded Clusters: A Parameter Space Survey
• Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. I. Observational overview and first results
• Inconsistency in theories of violent-relaxation
• Kinematic Signatures of Subvirial Initial Conditions in Young Clusters
• Reconstructing the Arches I: Constraining the Initial Conditions
• The Effect of Many Minor Mergers on the Size Growth of Compact Quiescent Galaxies
• A numerical comparison of theories of violent relaxation

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• Dynamical evolution of star forming regions - II. Basic kinematics
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