On the Curious Pulsation Properties of the Accreting Millisecond Pulsar IGR J17379-3747

Peter Bult, Craig B. Markwardt, Diego Altamirano, Zaven Arzoumanian, Deepto Chakrabarty, Keith C. Gendreau, Sebastien Guillot, Gaurava K. Jaisawal, Paul S. Ray, Tod E. Strohmayer

    Research output: Contribution to journalJournal articleResearchpeer-review

    94 Downloads (Pure)


    We report on the Neutron Star Interior Composition Explorer (NICER) monitoring campaign of the 468 Hz accreting millisecond X-ray pulsar IGR J17379-3747. From a detailed spectral and timing analysis of the coherent pulsations we find that they show a strong energy dependence, with soft thermal emission lagging about 640 µs behind the hard, Comptonized emission. Additionally, we observe uncommonly large pulse fractions, with measured amplitudes in excess of 20% sinusoidal fractional amplitude across the NICER passband and fluctuations of up to similar to 70%. Based on a phase-resolved spectral analysis, we suggest that these extreme properties might be explained if the source has an unusually favorable viewing geometry with a large magnetic misalignment angle. Due to these large pulse fractions, we were able to detect pulsations down to quiescent luminosities (similar to 5 x 1033 erg s-1. We discuss these low-luminosity pulsations in the context of transitional millisecond pulsars.
    Original languageEnglish
    Article number70
    JournalAstrophysical Journal
    Issue number2
    Number of pages12
    Publication statusPublished - 2019


    • Stars: neutron
    • X-rays: binaries
    • X-rays: individual (IGR J17379-3747)


    Dive into the research topics of 'On the Curious Pulsation Properties of the Accreting Millisecond Pulsar IGR J17379-3747'. Together they form a unique fingerprint.

    Cite this