Measurement of Black Hole Spin via X-ray Reflection Spectra

The measurement of black hole spin is of great significance. The methods of measuring the spin have been discussed for a long time. For this important astrophysical problem, the paper begins with the significance of measuring a black hole spin and focuses on the theory of measuring the spin via the X-ray reflection recognized as iron line spectrum method. The paper also discusses the popular reflection models and explains the important parameters. Besides, the other methods of spin measurement are introduced, mainly comparing them with the X-ray reflection method. Finally, the advantages and disadvantages of the X-ray reflection method are summarized.