Multi-wavelength studies of black hole X-ray binaries

Black hole X-ray binaries (BHXRB) are variable sources in multi-wavelength bands, especially behave as transient and bright X-ray and radio sources in the sky. In this review paper, we introduce the outbursts of black hole X-ray binaries, including multiwavelength observations, changes of accretion states and radiation models.We review the analyzed methods and present the status on measurements of black hole mass and spin, which are the fundamental parameters of black holes and are keys to understanding the birth, evolution and radiation properties of black hole systems. During the outbursts of black hole X-ray binaries, X-ray light curves also show a special timing feature, named as quasi-periodic oscillations (QPOs) with frequencies ranging from ~ 0.1 — 100 Hz, which reflect the dynamics of accreting plasma near the black holes. We discuss the multi-wavelength discoveries of quasi-periodic oscillations in BHXRBs, specially including the new features in X-ray bands and radio QPOs, the possible physical models and implications for black hole physics.