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  • A BAYESIAN APPROACH TO LOCA...
    CONN, A. R; IBATA, R. A; FERGUSON, A. M. N; CHAPMAN, S. C; VALLS-GABAUD, D; LEWIS, G. F; PARKER, Q. A; ZUCKER, D. B; MARTIN, N. F; MCCONNACHIE, A. W; IRWIN, M. J; TANVIR, N; FARDAL, M. A

    The Astrophysical journal, 10/2012, Letnik: 758, Številka: 1
    Journal Article

    In "A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part I)," a new technique was introduced for obtaining distances using the tip of the red giant branch (TRGB) standard candle. Here we describe a useful complement to the technique with the potential to further reduce the uncertainty in our distance measurements by incorporating a matched-filter weighting scheme into the model likelihood calculations. In this scheme, stars are weighted according to their probability of being true object members. We then re-test our modified algorithm using random-realization artificial data to verify the validity of the generated posterior probability distributions (PPDs) and proceed to apply the algorithm to the satellite system of M31, culminating in a three-dimensional view of the system. Finally, a preliminary investigation into the satellite density distribution within the halo is made using the obtained distance distributions. For simplicity, this investigation assumes a single power law for the density as a function of radius, with the slope of this power law examined for several subsets of the entire satellite sample.