Fig. 4: The dependence of the reflection fraction on the corona height and the bulk velocity.
From: Insight-HXMT observations of jet-like corona in a black hole X-ray binary MAXI J1820+070

The dimensionless reflection fraction Rf, is estimated as a function of the corona height H (in units of Rg) and the bulk velocity β = υ/c. The dashed line corresponds to the reflection fraction Rf = 1.0. The color bar represents the dimensionless reflection fraction, with the minimum and maximum being 0.1 and 6.4, respectively.