Spectral and Timing Properties of MAXI J1535-571 during its 2017 outburst
Abstract
We present spectral and timing analysis results of the newly-discovered X-ray transient source MAXI J1535-571, which is likely a Galactic black hole binary. It was discovered on 2017 Sep. 02. During the soft/high state, the maximum X-ray flux in 0.3-10 keV band increased by 25 times than that in the quiescent state, which is about 4 Crab. Using the Swift XRT & BAT observations, we study accretion flow processes around the black hole from spectral fits with the Two-Component Advective Flow (TCAF) model in XSPEC. Significant emission lines from neutral Fe K_ and Fe XXV K_ are observed. Type-C QPOs are also significantly detected in the raising and the declining phases of the outburst. Propagating Oscillatory Shock (POS) model is used to study monotonic evolution of the QPO frequencies during the declining phase of the outburst. This allowed us to have a rough estimation of the evolution of the central Compton cloud region (known as CENtrifugal pressure supported BOundary Layer; CENBOL) by measuring instantaneous locations, strength, velocity etc. of the propagating shock wave. The shock parameters obtained from POS model fit is also found to be consistent with the TCAF model fitted shock parameters. It has been observed that the CENBOL shrinks in the rising phase and expands in the declining phase of the outburst. We also estimate mass of the black hole candidate to be 10 solar masses from our TCAF model fitted spectral fits, suggesting that it is a stellar mass black hole system.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E3069S