NICER Detects a Soft X-Ray Kilohertz Quasi-periodic Oscillation in 4U 0614+09

Peter Bult, Diego Altamirano, Zaven Arzoumanian, Edward M. Cackett, Deepto Chakrabarty, John Doty, Teruaki Enoto, Keith C. Gendreau, Sebastien Guillot, Jeroen Homan, Gaurava K. Jaisawal, Frederick K. Lamb, Renee M. Ludlam, Simin Mahmoodifar, Craig Markwardt, Takashi Okajima, Sam Price, Tod E. Strohmayer, Luke Winternitz

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We report on the detection of a kilohertz quasi-periodic oscillation (QPO) with the Neutron Star Interior Composition Explorer ( NICER). Analyzing approximately 165 ks of NICER exposure on the X-ray burster 4U 0614+09, we detect multiple instances of a single-peak upper kHz QPO, with centroid frequencies that range from 400 to 750 Hz. We resolve the kHz QPO as a function of energy, and measure, for the first time, the QPO amplitude below 2 keV. We find the fractional amplitude at 1 keV is on the order of 2% rms, and discuss the implications for the QPO emission process in the context of Comptonization models.
Original languageEnglish
Article numberL9
JournalAstrophysical Journal Letters
Issue number1
Number of pages6
Publication statusPublished - 2018


  • Accretion
  • Accretion disks
  • Stars: neutron
  • X-rays: binaries
  • X-rays: individual (4U 0614+09)

Cite this

Bult, P., Altamirano, D., Arzoumanian, Z., Cackett, E. M., Chakrabarty, D., Doty, J., Enoto, T., Gendreau, K. C., Guillot, S., Homan, J., Jaisawal, G. K., Lamb, F. K., Ludlam, R. M., Mahmoodifar, S., Markwardt, C., Okajima, T., Price, S., Strohmayer, T. E., & Winternitz, L. (2018). NICER Detects a Soft X-Ray Kilohertz Quasi-periodic Oscillation in 4U 0614+09. Astrophysical Journal Letters, 860(1), [L9].