On the Curious Pulsation Properties of the Accreting Millisecond Pulsar IGR J17379–3747
Name
Bult_2019_ApJ_877_70.pdf
Description
Published version
Size
2.56 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Bult, Peter
Markwardt, Craig B
Altamirano, Diego
Arzoumanian, Zaven
Chakrabarty, Deepto
Gendreau, Keith C
Guillot, Sebastien
Jaisawal, Gaurava K
Ray, Paul S
Strohmayer, Tod E
Date Issued
2019
Journal
Astrophysical Journal
Publisher
American Astronomical Society
Version
Final published version
Abstract
© 2019. The American Astronomical Society. All rights reserved.. 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 ∼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 ( erg ). We discuss these low-luminosity pulsations in the context of transitional millisecond pulsars.
MIT Department
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.3847/1538-4357/AB1B26
