An Improved Distance to NGC 4258 and Its Implications for the Hubble Constant

  title={An Improved Distance to NGC 4258 and Its Implications for the Hubble Constant},
  author={Mark J. Reid and Dominic W. Pesce and Adam G. Riess},
  journal={The Astrophysical Journal Letters},
NGC 4258 is a critical galaxy for establishing the extragalactic distance scale and estimating the Hubble constant ( ). Water masers in the nucleus of the galaxy orbit about its supermassive black hole, and very long baseline interferometric observations of their positions, velocities, and accelerations can be modeled to give a geometric estimate of the angular-diameter distance to the galaxy. We have improved the technique to obtain model parameter values, reducing both statistical and… 

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