{
  "id": "1507.04372",
  "version": "v1",
  "published": "2015-07-15T20:09:29.000Z",
  "updated": "2015-07-15T20:09:29.000Z",
  "title": "The initial conditions of observed star clusters - I. Method description and validation",
  "authors": [
    "J. T. Pijloo",
    "S. F. Portegies Zwart",
    "P. E. R. Alexander",
    "M. Gieles",
    "S. S. Larsen",
    "P. J. Groot",
    "B. Devecchi"
  ],
  "comment": "39 pages, 28 figures, accepted for publication in MNRAS",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "We have coupled a fast, parametrized star cluster evolution code to a Markov Chain Monte Carlo code to determine the distribution of probable initial conditions of observed star clusters, which may serve as a starting point for future $N$-body calculations. In this paper we validate our method by applying it to a set of star clusters which have been studied in detail numerically with $N$-body simulations and Monte Carlo methods: the Galactic globular clusters M4, 47 Tucanae, NGC 6397, M22, $\\omega$ Centauri, Palomar 14 and Palomar 4, the Galactic open cluster M67, and the M31 globular cluster G1. For each cluster we derive a distribution of initial conditions that, after evolution up to the cluster's current age, evolves to the currently observed conditions. We find that there is a connection between the morphology of the distribution of initial conditions and the dynamical age of a cluster and that a degeneracy in the initial half-mass radius towards small radii is present for clusters which have undergone a core collapse during their evolution. We find that the results of our method are in agreement with $N$-body and Monte Carlo studies for the majority of clusters. We conclude that our method is able to find reliable posteriors for the determined initial mass and half-mass radius for observed star clusters, and thus forms an suitable starting point for modeling an observed cluster\\rq{}s evolution.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-07-15T20:09:29.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "initial conditions",
      "method description",
      "star cluster evolution code",
      "markov chain monte carlo code",
      "validation"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 39,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}