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arXiv · 1610.08653

Detection of Very Low-Frequency Quasi-Periodic Oscillations in the 2015 Outburst of V404 Cygni

D. Huppenkothen·G. Younes·A. Ingram·C. Kouveliotou·E. Göğüş·M. Bachetti·C. Sánchez-Fernández·J. Chenevez·S. Motta·M. van der Klis·J. Granot·N. Gehrels·E. Kuulkers·J. A. Tomsick·D. J. Walton
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Abstract

In June 2015, the black hole X-ray binary (BHXRB) V404 Cygni went into outburst for the first time since 1989. Here, we present a comprehensive search for quasi-periodic oscillations (QPOs) of V404 Cygni during its recent outburst, utilizing data from six instruments on board five different X-ray missions: Swift/XRT, Fermi/GBM, Chandra/ACIS, INTEGRAL's IBIS/ISGRI and JEM-X, and NuSTAR. We report the detection of a QPO at 18 mHz simultaneously with both Fermi/GBM and Swift/XRT, another example of a rare but slowly growing new class of mHz-QPOs in BHXRBs linked to sources with a high orbital inclination. Additionally, we find a duo of QPOs in a Chandra/ACIS observation at 73 mHz and 1.03 Hz, as well as a QPO at 136 mHz in a single Swift/XRT observation that can be interpreted as standard Type-C QPOs. Aside from the detected QPOs, there is significant structure in the broadband power, with a strong feature observable in the Chandra observations between 0.1 and 1 Hz. We discuss our results in the context of current models for QPO formation.

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D. Huppenkothen, G. Younes, A. Ingram, C. Kouveliotou, E. Göğüş, M. Bachetti, C. Sánchez-Fernández, J. Chenevez, S. Motta, M. van der Klis, J. Granot, N. Gehrels, E. Kuulkers, J. A. Tomsick, D. J. Walton. 2017-02-06. Detection of Very Low-Frequency Quasi-Periodic Oscillations in the 2015 Outburst of V404 Cygni. https://doi.org/10.3847/1538-4357%2F834%2F1%2F90

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