GRS 1915 contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, a disk forms. The black hole in GRS 1915 has been estimated to rotate at the maximum possible rate, allowing material in the inner disk to orbit very close to the black hole -- at a radius only 20% larger than the event horizon -- where the material travels at 50% the speed of light.
Researchers monitored this black hole system with Chandra and RXTE over a period of eight hours. As they watched, GRS 1915 gave off a short, bright pulse of X-ray light approximately every 50 seconds. This type of rhythmic cycle closely resembles an electrocardiogram of a human heart -- though at a slower pace. It was previously known that GRS 1915 can develop such heartbeats, but researchers gained new understanding into what drives the beats, and used the pulses to figure out what controls how much material the black hole consumes from the RXTE data.
Fast Facts for GRS 1915+105:
Scale: 5 degrees across (58 light years)
Category: Black Holes, Neutron Stars/X-ray Binaries
Coordinates: (J2000) RA 19h 15m 11.60s | Dec +10° 56' 44.00''
Observation Date: May 23rd, 2001
Observation Time: 8 hours 20 min
Obs. ID: 1945
Color Code: X-ray (Violet); Optical (Red, Green, Blue)
Distance Estimate: 40,000 light years