Observations over the past 20 years have revealed a strong relationship between the properties of the supermassive black hole ( SMBH ) lying at the center of a galaxy and the host galaxy itself .
The magnitude of the spin of the black hole will play a key role in determining the nature of this relationship .
To date , direct estimates of black hole spin have been restricted to the local Universe .
Herein , we present the results of an analysis of \sim 0.5 Ms of archival Chandra observations of the gravitationally lensed quasar Q 2237+305 ( aka the “ Einstein-cross ” ) , lying at a redshift of z = 1.695 .
The boost in flux provided by the gravitational lens allows constraints to be placed on the spin of a black hole at such high redshift for the first time .
Utilizing state of the art relativistic disk reflection models , the black hole is found to have a spin of a _ { * } = 0.74 ^ { +0.06 } _ { -0.03 } at the 90 % confidence level .
Placing a lower limit on the spin , we find a _ { * } \geq 0.65 ( 4 \sigma ) .
The high value of the spin for the \sim 10 ^ { 9 } ~ { } M _ { \sun } black hole in Q 2237+305 lends further support to the coherent accretion scenario for black hole growth .
This is the most distant black hole for which the spin has been directly constrained to date .