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

[摘要] (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 (~5 x 10(exp 33) erg/s).

[发布日期] 2019-05-28

[学科分类] 天体物理学

[关键词] ASTROPHYSICS;BRIGHTNESS;COMPTON EFFECT;GAMMA RAYS;LUMINOSITY;NEUTRON STARS;PULSARS;SPECTRUM ANALYSIS;TIME MEASUREMENT;THERMAL EMISSION;UNSTEADY FLOW;X RAY BINARIES;X RAY TIMING EXPLORER