The formation of a black hole [
http://imagine.gsfc…black_holes.html ] from the collapsing core of a massive star is thought to be heralded by a spectacular supernova explosion. Such an extremely energetic collapse is also a leading explanation [
http://arxiv.org/ab…] for the mysterious cosmic gamma-ray bursts [
http://antwrp.gsfc.…]. But researchers now suggest that the Milky Way's most famous black hole, Cygnus X-1 [
http://www.eso.org/…austria_cygnus_1/ ], was born when a massive star collapsed -- without any supernova explosion [
http://arxiv.org/ab…] at all. Their dynamical evidence is summarized in this color image of a gorgeous region in Cygnus [
http://imagine.gsfc…cygX1-more3.html ], showing Cyg X-1 and a cluster of massive stars (yellow circles) known as Cygnus OB3. Arrows compare the measured direction and speed of Cyg X-1 and the average direction and speed of the massive stars of Cyg OB3. The similar motions indicate that Cyg X-1's progenitor star was itself a cluster member and that its path was not altered at all when it became a black hole. In contrast, if Cyg X-1 were born in a violent supernova it would have likely received a fierce kick [
http://hubblesite.o…], changing its course. If not a supernova, could the formation [
http://saturn.sron.…] of the Cyg X-1 black hole have produced a dark [
http://swift.gsfc.n…archive/2002/02-257. html ] gamma-ray burst in the Milky Way [
http://www.pbs.org/…]?
Explanation
The formation of a black hole [
http://imagine.gsfc…black_holes.html ] from the collapsing core of a massive star is thought to be heralded by a spectacular supernova explosion. Such an extremely energetic collapse is also a leading explanation [
http://arxiv.org/ab…] for the mysterious cosmic gamma-ray bursts [
http://antwrp.gsfc.…]. But researchers now suggest that the Milky Way's most famous black hole, Cygnus X-1 [
http://www.eso.org/…austria_cygnus_1/ ], was born when a massive star collapsed -- without any supernova explosion [
http://arxiv.org/ab…] at all. Their dynamical evidence is summarized in this color image of a gorgeous region in Cygnus [
http://imagine.gsfc…cygX1-more3.html ], showing Cyg X-1 and a cluster of massive stars (yellow circles) known as Cygnus OB3. Arrows compare the measured direction and speed of Cyg X-1 and the average direction and speed of the massive stars of Cyg OB3. The similar motions indicate that Cyg X-1's progenitor star was itself a cluster member and that its path was not altered at all when it became a black hole. In contrast, if Cyg X-1 were born in a violent supernova it would have likely received a fierce kick [
http://hubblesite.o…], changing its course. If not a supernova, could the formation [
http://saturn.sron.…] of the Cyg X-1 black hole have produced a dark [
http://swift.gsfc.n…archive/2002/02-257. html ] gamma-ray burst in the Milky Way [
http://www.pbs.org/…]?
Explanation
