Tracing a Z-track in the M31 X-ray Binary RX J0042.6+4115

R. Barnard; U. Kolb; J. P. Osborne

doi:10.1051/0004-6361:20031513

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Tracing a Z-track in the M31 X-ray Binary RX J0042.6+4115

R. Barnard·U. Kolb·J. P. Osborne

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Abstract

Four XMM-Newton observations of the core of M31, spaced at 6 month intervals, show that the brightest point X-ray source, RX J0042.6+4115, has a 0.4-10 keV luminosity of ~5 10^38 erg/s, and exhibits significant variability in intensity and X-ray spectrum over a time scale of ~100 s including hard flares; such behaviour is only observed in Z-sources and transient blackhole binaries in our Galaxy. The lightcurves, X-ray spectra and hardness-intensity data from the four XMM-Newton observations all strongly suggest that it is a Z-source, bringing the total number of known Z-sources to nine.

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R. Barnard, U. Kolb, J. P. Osborne. 2003-09-26. Tracing a Z-track in the M31 X-ray Binary RX J0042.6+4115. https://doi.org/10.1051/0004-6361%3A20031513

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