A Seyfert-2-like Spectrum in the High-Mass X-ray Binary Microquasar V4641 Sgr
Abstract
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.
Keywords
Cite
@article{arxiv.1402.6665,
title = {A Seyfert-2-like Spectrum in the High-Mass X-ray Binary Microquasar V4641 Sgr},
author = {W. R. Morningstar and J. M. Miller and M. T. Reynolds and D. Maitra},
journal= {arXiv preprint arXiv:1402.6665},
year = {2015}
}
Comments
Accepted for publication in ApJ Letters