Prior to the detection of gravitational waves, most black holes (excepting supermassive ones) were discovered through X-ray studies.From the figure below, what is different about the black holes detected through gravitational waves, and why might this be the case? 
Definitions:
Equilibrium Output
The level of production at which the quantity of goods supplied equals the quantity of goods demanded, leading to market stability.
Diagram
A simplified drawing using lines and symbols to represent structures, systems, or processes, aiding in the explanation or analysis of data and concepts.
Payoff Matrix
A table that shows the potential outcomes of different strategies in a decision-making process, typically used in game theory to analyze interactions between multiple players.
Duopoly
A market structure where only two sellers compete directly against each other, offering similar goods or services.
Q1: The main-sequence lifetime of a star is
Q3: What are the main observational difficulties in
Q33: When a spectral-type G2 star like the
Q34: List three methods of energy transport in
Q57: Explain the different types of redshift you
Q70: Given the figure below, explain the three
Q76: If you observe a maximum number of
Q82: The collapse of the core of a
Q85: The net effect of the proton-proton chain
Q92: If there is a 4 million M<sub>SUN</sub>