The Temporal Phenomena during the Outburst of the Black Hole Candidate MAXI J1535-571

Using the observations of the black hole candidate MAXI J1535-571 by the Hard X-ray Modulation Telescope (Insight-HXMT) in September 2017, the temporal phenomena of the source during the outburst period are studied. There are significant differences in the power density spectra when the source is in different outburst states. And in the hard intermediate state, there are obvious band-limited noise components and QPO (Quasi-Periodic Oscillation) components. The analysis results show that the characteristic frequency of low frequency band-limited noise is positively correlated with the energy, i.e. the characteristic frequency of photons in soft energy band is less than that in hard energy band. The band-limited noise RMS (Root Mean Square) spectra in the 0.1--0.5Hz show peaks in both the hard and soft intermediate states, and there are differences at the high energy, probably due to the ratio of the energy spectrum components of the dominant noise RMS is different. The type-C QPO RMS spectrum maintains a similar trend when the spectral state is from the hard intermediate state to the soft intermediate state. But there is a spectral state dependence in the band-limited noise RMS spectrum, implying that the noise and QPO have different mechanisms of origin.