Polarization measurements of the microquasar Cygnus X-1 exist at γ-ray, X-ray, ultraviolet, optical and radio frequencies. The γ-ray emission has been shown to...
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PublicationThe multiwavelength polarization of Cygnus X-1
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PublicationThe Nature of the UV/Optical Emission of the Ultraluminous X-Ray Source in Holmberg II
We report on UV and X-ray spectroscopy and broadband optical observations of the ultraluminous X-ray source in Holmberg II. Fitting various stellar spectral...
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PublicationThe Origin and Evolution of the Black Hole Binary XTE J1118+480
Black hole X-ray binaries with large mass ratios and short orbital periods are expected to change their orbital period due to magnetic breaking, mass loss...
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PublicationThe photocentre-AGN displacement: is M87 actually harbouring a displaced supermassive black hole?
M87 has been identified as a displaced supermassive black hole (SMBH) candidate. We investigated this possibility by a temporal analysis of 12 adaptive-optics...
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PublicationThe powerful jet of an off-nuclear intermediate-mass black hole in the spiral galaxy NGC 2276
Jet ejection by accreting black holes is a mass invariant mechanism unifying stellar and supermassive black holes (SMBHs) that should also apply for...
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PublicationThe scaling of X-ray variability with luminosity in ultra-luminous X-ray sources
Aims: We investigate the relationship between the X-ray variability amplitude and X-ray luminosity for a sample of 14 bright ultra-luminous X-ray sources (ULXs)...
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PublicationThe Spectrum of the Black Hole X-Ray Nova V404 Cygni in Quiescence as Measured by XMM-Newton
We present XMM-Newton observations of the black hole X-ray nova V404 Cyg in quiescence. Its quiescent spectrum can be best fitted by a simple power law with...
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PublicationThe ultraluminous X-ray source NGC 1313 X-2. Its optical counterpart and environment
NGC 1313 X-2 is one of the brightest ultraluminous X-ray sources in the sky, at both X-ray and optical wavelengths; therefore, quite a few studies of available...
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PublicationThe X-ray transient XTE J1859 + 226 in outburst and quiescence
We present optical photometry and spectroscopy of the X-ray transient XTE J1859+226, obtained during outburst and its subsequent decay to quiescence. Both the X...