Distinguishing an ejected blob from alternative flare models at the   Galactic centre with GRAVITY
  The black hole at the Galactic centre exhibits regularly flares of radiation, the origin of which is still not understood. In this article, we study the ability of the near-future GRAVITY infrared instrument to constrain the nature of these events. We develop realistic simulations of GRAVITY astrometric data sets for various flare models. We show that the instrument will be able to distinguish an ejected blob from alternative flare models, provided the blob inclination is >= 45deg, the flare brightest magnitude is 14 <= mK <= 15 and the flare duration is >= 1h30. 
F. H. Vincent, T. Paumard, G. Perrin, P. Varniere, F. Casse, F.   Eisenhauer, S. Gillessen and P. J. Armitage
astro-ph.HE