Accretion scenario of MAXI J1820+070 during 2018 outbursts with multimission observations

We present a comprehensive spectral and temporal study of the black hole X-ray transient MAXI J1820+070 during its outbursts in 2018 using Swift/XRT, NICER, NuSTAR AstroSat observations. The Swift/XRT NICER shows plateau light curve with softening (hardness changes from $\sim$ $2.5$ to $2$) followed by gradual decline without first outburst. Also, modelling suggests that outburst is low/hard state throughout truncated disk whereas thermal emission dominates second During entire outburst, strong reflection signature (reflection fraction varies between $0.38 - 3.8$) observed simultaneous wideband (NICER-NuSTAR, XRT-NuSTAR, AstroSat) data due presence dynamically evolving corona. timing analysis Quasi-periodic Oscillation (QPO) signatures characteristic frequency increases (decreases) (decline) phase time understand reduction electron cooling timescale corona resonance oscillation local dynamical may explain above behavior source we propose possible scenario triggering associated accretion geometry source.