Now some astronomers have done the same for an intermediate mass black hole (IMBH) in the galaxy M82, which lies between the stellar-mass objects like Cygnus X-1 and the huge supermassive black holes at the centers of most galaxies. The evidence for the existence of IMBHs has often been ambiguous, though: other researchers have argued the black hole in M82 is stellar-mass. However, if the song of the black hole is to be believed, it’s about 400 times the mass of the Sun — too big to be stellar-mass, but far too small to be supermassive.
For low-mass black holes, the pattern is the juxtaposition of two evenly-timed bursts of light with three flares in the same time interval. Music aficionados recognize this rhythm as a triplet or “hemiola”: the playing of two different musical patterns simultaneously. Another musical metaphor: if we interpret the frequencies as notes instead of rhythms, the ratio of 3 to 2 is known as a “perfect fifth” in harmony, the foundation of any number of chords. Low-mass black holes “sing” in harmony with themselves, though with flashes of light instead of sound.
Do middleweight black holes do the same? [Read more...]
Speaking of black holes! I am teaching a new class on some of the wilder aspects of black hole science next month: black hole thermodynamics, quantum gravitational aspects of the event horizon, Hawking radiation, the holographic principle, firewalls, and the like. Sign up today!