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Disc precession to explain the superorbital modulation of LMC X-4: results from the Swift monitoring campaign.
- Source :
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Monthly Notices of the Royal Astronomical Society . 5/30/2022, Vol. 512 Issue 3, p3422-3435. 14p. - Publication Year :
- 2022
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Abstract
- We studied the spectral changes of the high-mass X-ray binary system LMC X-4 to understand the origin and mechanisms beyond its superorbital modulation (30.4 d). To this aim, we obtained a monitoring campaign with Swift /XRT (0.3–10 keV) and complemented these data with the years-long Swift /BAT survey data (15–60 keV). We found a self-consistent, physically motivated, description of the broad-band X-ray spectrum using a Swift /XRT and a NuSTAR observation at the epoch of maximum flux. We decomposed the spectrum into the sum of a bulk + thermal Comptonization, a disc reflection component, and a soft contribution from a standard Shakura–Sunyaev accretion disc. We applied this model to 20 phase-selected Swift spectra along the superorbital period. We found a phase-dependent flux ratio of the different components, whereas the absorption column does not vary significantly. The disc emission is decoupled with respect to the hard flux. We interpret this as a geometrical effect in which the inner parts of the disc are tilted with respect to the obscuring outer regions. [ABSTRACT FROM AUTHOR]
- Subjects :
- *X-ray binaries
*ACCRETION disks
*X-ray spectra
Subjects
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 512
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 156326812
- Full Text :
- https://doi.org/10.1093/mnras/stac450