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Investigating a unique partial eclipse in the high-mass X-ray binary IGR J16393−4643 with Swift-XRT

Kabiraj, S and Islam, N and Paul, B (2020) Investigating a unique partial eclipse in the high-mass X-ray binary IGR J16393−4643 with Swift-XRT. In: Monthly Notices of the Royal Astronomical Society, 491 (1). pp. 1491-1497.

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Official URL: https://doi.org/10.1093/mnras/stz3082


The orbital profile of the high-mass X-ray binary IGR J16393−4643 shows a dip in its X-ray intensity, which was previously interpreted as an eclipse. Unlike most eclipsing HMXBs, where the X-ray eclipses are about two orders of magnitude fainter compared to the out-of-eclipse emission, this particular eclipse-like feature is narrow and partial, casting doubt if it is indeed an eclipse. To further investigate the nature of this low-intensity orbital phase, we use a large number of observations with Swift-XRT, covering the entire orbital phase. The soft X-ray observations also show this low-intensity phase, which is about 30 % of the intensity during rest of the orbit. We also carried out orbital-phase-resolved spectroscopy to compare the change in the spectral parameters inside and outside of this low-intensity state. The results indicate that this low-intensity state might not be an eclipse, as previously thought but absorption in the stellar corona. We have also provided the inclination angle of the binary for grazing eclipse caused by the stellar corona.

Item Type: Journal Article
Publication: Monthly Notices of the Royal Astronomical Society
Publisher: Oxford University Press
Additional Information: The copyright for this article belongs to to the Authors.
Keywords: Binaries:eclipsing; High mass X ray binaries; Low-intensity; Orbital phase; Stars: neutrons; Stellar coronae; X-ray: individual: IGR j16393-4643; X-ray:stars; X-rays: Binaries; X-rays: individual, Stars
Department/Centre: Division of Physical & Mathematical Sciences > Astronomy and Astrophysics Programme
Date Deposited: 24 Jan 2023 04:49
Last Modified: 24 Jan 2023 04:49
URI: https://eprints.iisc.ac.in/id/eprint/79309

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