Variability study of the high-mass X-ray binary IGR J18027−2016 with Swift-XRT. Issue 2 (16th August 2016)

• Record Type: Journal Article
• Authors: Aftab, Nafisa; Islam, Nazma; Paul, Biswajit
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 463:Issue 2(2016)
• Page Start: 2032
• Page End: 2038
• Publication Date: 2016-08-16
• Subjects: binaries: eclipsing -- stars: neutron -- X-rays: individual: IGR J18027−2016 -- X-rays: stars; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stw2037
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We report the results from pulsations and spectral analysis of a large number of observations of the high-mass X-ray binary pulsar IGR J18027−2016 with Swift X-ray Telescope (XRT), carried out at different orbital phases. In some orbital phases, as seen in different XRT observations, the X-ray intensity is found to vary by a large factor, of about ∼50. In all the observations with sufficient number of source X-ray photons, pulsations have been detected around the previously known pulse period of ∼140 s. When detected, the pulse profiles do not show any significant variation over a flux difference of a factor of ∼3. The absorption column density is found to be large before and after the eclipse. We discuss various possible reasons for intensity and spectral variations in IGR J18027−2016, such as clumpy wind and hydrodynamic instabilities.