Using the Very Long Baseline Array , we have measured a trigonometric parallax for the microquasar GRS 1915+105 , which contains a black hole and a K-giant companion .
This yields a direct distance estimate of 8.6 ^ { +2.0 } _ { -1.6 } kpc and a revised estimate for the mass of the black hole of 12.4 ^ { +2.0 } _ { -1.8 } M _ { \odot } .
GRS 1915+105 is at about the same distance as some H II regions and water masers associated with high-mass star formation in the Sagittarius spiral arm of the Galaxy .
The absolute proper motion of GRS 1915+105 is -3.19 \pm 0.03 mas y ^ { -1 } and -6.24 \pm 0.05 mas y ^ { -1 } toward the east and north , respectively , which corresponds to a modest peculiar speed of 22 \pm 24 km s ^ { -1 } at the parallax distance , suggesting that the binary did not receive a large velocity kick when the black hole formed .
On one observational epoch , GRS 1915+105 displayed superluminal motion along the direction of its approaching jet .
Considering previous observations of jet motions , the jet in GRS 1915+105 can be modeled with a jet inclination to the line of sight of 60 ^ { \circ } \pm 5 ^ { \circ } and a variable flow speed between 0.65 c and 0.81 c , which possibly indicates deceleration of the jet at distances from the black hole \gtrsim 2000 AU .
Finally , using our measurements of distance and estimates of black hole mass and inclination , we provisionally confirm our earlier result that the black hole is spinning very rapidly .