Accretion processes around compact objects

I will first plan to review the accretion phenomenology and underlying models, mostly for a black hole. I will attempt to touch upon, how over the decades with the evolution of observations with newer data, newer models are proposed to explain them: standard Shakura- Sunyaev Keplerian disk, advective sub-Keplerian disk, magnetically arrested (advective) disk, etc. Finally, I will aim to uncover two particular issues: QPOs and ULXs, based on one of the modern accretion theories.