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We present optical and X-ray data for the first object showing strong evidence for being a black hole in a globular cluster. We show the initial X-ray light curve and X-ray spectrum which led to the discovery that this is an extremely bright, highly variable source, and thus must be a black hole. We present the optical spectrum which unambiguously identifies the optical counterpart as a globular cluster, and which shows a strong, broad [O III] emission line, most likely coming from an outflow driven by the accreting source.
We present the discovery of [OIII] 5007 emission associated with the black hole X-ray binary recently identified in a globular cluster in the Virgo elliptical galaxy NGC 4472. This object is the first confirmed black-hole X-ray binary in a globular c luster. The identification of [OIII] 5007 emission from the black-hole hosting globular cluster is based on two independent fiber spectra obtained at the VLT with FLAMES, which cover a wavelength range of 5000-5800 Angstrom at a spectral resolution of about 6000. In each of these spectra we find an emission line at 5031.2 Angstrom with an uncertainty of several tenths of an Angstrom. These are consistent with [OIII] 5007 emission at the 1475 +/- 7 km/s radial velocity of the globular cluster previously determined from an analysis of its absorption lines. This agreement within the small uncertainties argues strongly in favor of the interpretation of the line as [OIII] 5007 emission from the black-hole hosting globular cluster. We also find that the emission line most likely has a velocity width of several hundred km/s. Such a velocity width rules out a planetary nebula explanation for the [OIII] 5007 emission and implicates the black hole as the source of the power driving the nebular emission.
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