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

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

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;   

RP-ID  :  GSFC-E-DAA-TN70604

学科分类：天体物理学

美国|英语

来源: NASA Technical Reports Server

【 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).