A Seyfert-2-like Spectrum in the High-Mass X-ray Binary Microquasar   V4641 Sgr
  We present an analysis of three archival Chandra observations of the black hole V4641 Sgr, performed during a decline into quiescence. The last two observations in the sequence can be modeled with a simple power-law. The first spectrum, however, is remarkably similar to spectra observed in Seyfert-2 active galactic nuclei, which arise through a combination of obscuration and reflection from distant material. This spectrum of V4641 Sgr can be fit extremely well with a model including partial-covering absorption and distant reflection. This model recovers a Gamma = 2 power-law incident spectrum, typical of black holes at low Eddington fractions. The implied geometry is plausible in a high-mass X-ray binary like V4641 Sgr, and may be as compelling as explanations invoking Doppler-split line pairs in a jet, and/or unusual Comptonization. We discuss potential implications and means of testing these models. 
W. R. Morningstar (1), J. M. Miller (1), M. T. Reynolds (1), D. Maitra   (2) ((1) University of Michigan, (2) Wheaton College)
astro-ph.HE