Spectro-timing analysis of MAXI J1535–571 using AstroSat. Issue 1 (28th June 2019)

• Record Type: Journal Article
• Authors: Bhargava, Yash; Belloni, Tomaso; Bhattacharya, Dipankar; Misra, Ranjeev
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 488:Issue 1(2019)
• Page Start: 720
• Page End: 727
• Publication Date: 2019-06-28
• Subjects: accretion, accretion discs -- black hole physics -- X-rays: binaries; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stz1774
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We report the results of the analysis of an AstroSat observation of the black hole candidate MAXI J1535–571 during its hard-intermediate state. We studied the evolution of the spectral and timing parameters of the source during the observation. The observation covered a period of ∼5 d and consisted of 66 continuous segments, corresponding to individual spacecraft orbits. Each segment was analysed independently. The source count rate increased roughly linearly by ∼30 per cent. We modelled the spectra as a combination of radiation from a thermal disc component and a power law. The timing analysis revealed the presence of strong quasi-periodic oscillations with centroid frequency νQPO fluctuating in the range of 1.7–3.0 Hz. We found a tight correlation between the QPO centroid frequency νQPO and the power-law spectral index Γ, while νQPO appeared not to be correlated with the linearly increasing flux itself. We discuss the implications of these results on physical models of accretion.