We present three simultaneous/quasi-simultaneous NuSTAR and Swift datasets of the black hole GRS 1716-249 in its hard intermediate state .
The accretion disk in this state may have reached the innermost stable circular orbit , and the NuSTAR spectra show a broad relativistic iron line and a strong Compton hump .
To measure the black hole spin , we construct a joint model consisting of a relativistic disk model kerrbb and a reflection model relxill , to fit the continuum and the reflection components , respectively .
By applying this model to each dataset independently , a consistent result is obtained on the black hole spin and the disk inclination .
The black hole spin is a ^ { \ast } \gtrsim 0.92 , and the inclination angle ( i ) is around 40–50 ^ { \circ } , based on the measurements of all datasets .
In the third dataset , a high black hole mass ( M _ { BH } ) is strongly disfavored by the spectral fits .
By unfreezing the black hole mass , we find a ^ { \ast } > 0.92 , i = 49.9 ^ { +1.0 \circ } _ { -1.3 } and M _ { BH } < 8.0 M _ { \odot } , at a 90 % confidence level .
Considering the lower limit derived from a previous optical constraint , M _ { BH } is in a range of 4.9 - 8.0 M _ { \odot } .