Simulation of GRS 1915+105's "Heartbeat"

GRS 1915+105 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+105 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 the Chandra X-ray Observatory and the Rossi X-ray Timing Explorer (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+105 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. This movie shows a simulation of the heartbeat variation of GRS 1915+105. It shows an X-ray point source varying with time, based on an average X-ray light curve of GRS 1915+105 obtained with RXTE. The period of the heartbeat variation has been sped up by a factor of 10 and four cycles of the variation are shown. credit: NASA/CXC/Harvard/J.Neilsen et al & A.Hobart source: http://chandra.harvard.edu/photo/2011/g1915/animations.html