Bhargava, YashYashBhargavaBELLONI, Tomaso Maria MelchiorreTomaso Maria MelchiorreBELLONIBhattacharya, DipankarDipankarBhattacharyaMisra, RanjeevRanjeevMisra2020-12-092020-12-0920190035-8711http://hdl.handle.net/20.500.12386/28762We 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 ν<SUB>QPO</SUB> fluctuating in the range of 1.7-3.0 Hz. We found a tight correlation between the QPO centroid frequency ν<SUB>QPO</SUB> and the power-law spectral index Γ, while ν<SUB>QPO</SUB> appeared not to be correlated with the linearly increasing flux itself. We discuss the implications of these results on physical models of accretion.STAMPAenArticle10.1093/mnras/stz17742-s2.0-85073723356000482319700056https://academic.oup.com/mnras/article/488/1/720/55250972019MNRAS.488..720BFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_6 Stars and stellar systems