Low-mass X-ray binaries from black-hole retaining globular clusters

Recent studies suggest that globular clusters (GCs) may retain a substantial population of stellar-mass black holes (BHs), in contrast to the long-held belief of a few to zero BHs. We model the population of BH low-mass X-ray binaries (BH-LMXBs), an ideal observable proxy for elusive single BHs, produced from a representative group of Milky Way GCs with variable BH populations. We simulate the formation of BH-binaries in GCs through exchange interactions between binary and single stars in the company of tens to hundreds of BHs. Additionally, we consider the impact of the BH population on the rate of compact binaries undergoing gravitational wave driven mergers. The characteristics of the BH-LMXB population and binary properties are sensitive to the GCs structural parameters as well as its unobservable BH population. We find that GCs retaining $\sim 1000$ BHs produce a galactic population of $\sim 150$ ejected BH-LMXBs whereas GCs retaining only $\sim20$ BHs produce zero ejected BH-LMXBs. Moreover, we explore the possibility that some of the presently known BH-LMXBs might have originated in GCs and identify five candidate systems.Comment: 27 pages, 18 figures, 7 tables, submitted to MNRA

Bisimulations, games and logic

In a recent paper by Joyal, Nielsen, and Winskel, bisimulation is defined in an abstract and uniform way across a wide range of di#erent models for concurrency . In this paper, following a recent trend in theoretical computer science, we characterize their abstract definition game-theoretically and logically in a non-interleaving model. Our characterizations appear as surprisingly simple extensions of corresponding characterizations of interleaving bisimulation. # Basic Research in Computer Science, Centre of the Danish National Research Foundation i Contents 1 Introduction 1 2 An Abstract Equivalence 4 3 Game Characterizations 8 3.1 Basic Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.2 A Characteristic Game for Interleaving Bisimulation . . . . . . 10 3.3 Allowing Opponent to Backtrack . . . . . . . . . . . . . . . . 12 4 A Path Logic 16 5 Conclusion 19 A Every Game Has a Winner 22 B Proofs From Section 3 22 B.1 From #-bisimilarity to #-equivalence . . . . . ..

Bisimulations, Games and Logic

In a recent paper by Joyal, Nielsen, and Winskel, bisimulation is defined in an abstract and uniform way across a wide range of different models for concurrency. In this paper, following a recent trend in theoretical computer science, we characterize their abstract definition game-theoretically and logically in a non-interleaving model. Our characterizations appear as surprisingly simple extensions of corresponding characterizations of interleaving bisimulation