Long-Term INTEGRAL and RXTE Observations of the X-Ray Pulsar LMC X-4

Abstract

We analyze the observations of the X-ray pulsar LMC X-4 performed by the INTEGRAL observatory and the All-Sky Monitor (ASM) of the RXTE observatory over a wide energy range. The observed hard X-ray flux from the source is shown to change by more than a factor of 50 (from ~70 mCrab in the high state to ~1.3 mCrab in the low state) on the time scale of the accretion-disk precession period, whose mean value for 1996-2004 was determined with a high accuracy, Pprec=30.275+/-0.004 days. In the low state, a flare about 10 h in duration was detected from the source; the flux from the source increased by more than a factor of 4 during this flare. The shape of the pulsar's broadband spectrum is essentially invariable with its intensity; no statistically significant features associated with the possible resonance cyclotron absorption line were found in the spectrum of the source.

arXiv comment16 pages, 5 figures, Astronomy Letters, 31, 380-387 (2005)

References in corpus (6)

• ISGRI: the INTEGRAL Soft Gamma-Ray Imager
• A Hard X-ray survey of the Galactic Center with INTEGRAL/IBIS. Catalog of sources
• Orbital Decay in LMC X-4
• Long-term Properties of Accretion Disks in X-ray Binaries: II. Stability of Radiation-Driven Warping
• The 0.1-100 keV Spectrum of LMC X-4 in the High State: Evidence for a High Energy Cyclotron Absorption Line
• Spectral variations of the X-ray binary pulsar LMC X-4 during its long period intensity variation and a comparison with Her X-1

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• AX J1749.1-2733 and AX J1749.2-2725 - the close pair of X-ray pulsars behind the Galactic Center: an optical identification
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• Peculiarities of super-Eddington flares from the X-ray pulsar LMC X-4 with NuSTAR
• Disk precession to explain the super-orbital modulation of LMC X-4: results from the Swift monitoring campaign
• Study of the X-ray Pulsar IGR J21343+4738 based on NuSTAR, Swift, and SRG data
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