Wednesday, February 24, 2010
Circinus Galaxy Black Hole
Wow. Its been quite a while. For some reason its taken me a few months to find the time/motivation to update this blog. Now that i'm done(for now at least) with Nebulae i'm gonna hit off on a few different things. First on the list is the Circinus Galaxy Black Hole. At the very center is an active galactic nucleus, where matter glows brightly before likely spiraling into a massive black hole. Although only 15 million light years distant, the Circinus Galaxy went unnoticed until 25 years ago because it is blocked by material in the plane of our own Galaxy. The galaxy can be seen with a small telescope, however, in the constellation of Circinus.
Circinus belongs to a class of mostly spiral galaxies called Seyferts, which have compact centers and are BELIEVED to contain massive black holes. The intensity of X-rays from the source changes on a cycle of 7.5 hours – the first time this "periodic variability" has been detected at X-ray wavelengths in an object outside the "Local Group" of galaxies. And, along with its brightness, this evidence strongly suggests that the system contains a black hole some 50 times the mass of the Sun. This is important because black holes with masses much larger than 10 times the mass of the Sun such as this one are difficult to explain under our current theories of star formation and destruction. Finding a periodic signal in one allows us to test some of our past assumptions.
"This Chandra X-ray image shows the inner portion of the Circinus Galaxy, with north at the top of the image and east to the left. In terms of X-ray energies, red represents low energy, green intermediate and blue the highest observed energies."