GRS 1915+105 or V1487 Aquilae is an X-ray binary star system which features a regular star and a black hole. It was discovered on August 15, 1992 by the WATCH all-sky monitor aboard Granat.^[5] "GRS" stands for "GRANAT source", "1915" is the right ascension (19 hours and 15 minutes) and "105" reflects the approximate declination (10 degrees and 56 arcminutes). The near-infrared counterpart was confirmed by spectroscopic observations.^[6] The binary system lies 11,000 parsecs away^[7] in Aquila. GRS 1915+105 is the heaviest of the stellar black holes so far known in the Milky Way Galaxy,^[8] with 10 to 18 times the mass of the Sun.^[9] It is also a microquasar, and it appears that the black hole rotates at least 950 times per second, close to the maximum of 1,150 times per second, with a spin parameter value between 0.82 and 1.00 (maximum possible value).^[10][11]

In 1994, GRS 1915+105 became the first known galactic source that ejects material with apparent superluminal motion velocities.^[12]

Observations with high resolution radio telescopes such as VLA, MERLIN, and VLBI show a bi-polar outflow of charged particles, which emit synchrotron radiation at radio frequencies. These studies have shown that the apparent superluminal motion is due to a relativistic effect known as relativistic aberration, where the intrinsic velocity of ejecta is actually about 90% the speed of light.^[7]

Repeat observations by the Chandra X-Ray Observatory over the period of a decade have revealed what may be a mechanism for self-regulation of the rate of growth of GRS 1915+105. The jet of materials being ejected is occasionally choked off by a hot wind blowing off the accretion disk. The wind deprives the jet of materials needed to sustain it. When the wind dies down, the jet returns.^[13]

• GRO J1655-40