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rfmcdonaldThe idea of black holes, places where reality is literally bent far far out of shape, has comfortably inhabited popular culture in the few decades since astronomers discovered that Einstein's laws did allow for the creation of these magical spaces. A massive star's death really could remove an area of space-time from observation, this censorship of reality surrounding the very single singularity where (mathematicians suggest) anything could be generated. (Do you believe in magic? It might exist, there.)
The first black hole candidate discovered was Cygnus X-1, a radio source orbiting a blue supergiant star some six thousand light years away, found in 1964 by some of the first dedicated astronomical observatories positioned beyond Earth's hazy of atmosphere. For years, there has been debate as increasingly precise observations have made the preliminary identification of Cygnus X-1 as a black hole and not some other object tighter. Centauri Dreams announced a couple of years ago that three recently published papers make the identification a sure thing.
I've not heard of stellar-mass black holes being formed without supernova explosions before.
The first black hole candidate discovered was Cygnus X-1, a radio source orbiting a blue supergiant star some six thousand light years away, found in 1964 by some of the first dedicated astronomical observatories positioned beyond Earth's hazy of atmosphere. For years, there has been debate as increasingly precise observations have made the preliminary identification of Cygnus X-1 as a black hole and not some other object tighter. Centauri Dreams announced a couple of years ago that three recently published papers make the identification a sure thing.
The new work draws on data from a wide variety of instruments. Optical observations of the unseen black hole’s motion around the massive blue companion star it orbits yield the most precise determination of the mass of Cygnus X-1 ever made — the asteroid-sized body is 14.8 times the mass of the Sun, making it one of the most massive stellar black holes in the galaxy. Moreover, data from the Chandra X-ray Observatory, the Rossi X-ray Timing Explorer, and the Advanced Satellite for Cosmology and Astrophysics reveal that the black hole’s event horizon is spinning more than 800 times per second, a spin as fast as any that have been analyzed.
Image: On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box. Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across. An artist’s illustration on the right depicts what astronomers think is happening within the Cygnus X-1 system. Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star. The black hole pulls material from a massive, blue companion star toward it. This material forms a disk (shown in red and orange) that rotates around the black hole before falling into it or being redirected away from the black hole in the form of powerful jets. Credit: Optical: DSS; Illustration: NASA/CXC/M.Weiss.
The precise spin and mass findings relied on new estimates of the distance of this object using the National Radio Observatory’s Very Long Baseline Array, which pegged the black hole at 6,070 light years from Earth. The relatively slow motion of Cygnus X-1 through the Milky Way implies, according to this Chandra news release, that the black hole was not produced by a supernova, but may have been the result of a massive star that collapsed without an explosion.
I've not heard of stellar-mass black holes being formed without supernova explosions before.
