a former fellow grad student, eva noyola, has discovered an intermediate-mass black hole at the center of the globular cluster, omega centauri! a globular cluster is a group of stars all born from the same cloud of gas and gravitationally bound to each other. they are less massive and smaller than what we call a galaxy, but they still have a very large amount of stars!!
to discover the black hole, they used images from the hubble space telescope to identify stars very close to the center of the globular cluster. then used the gemini-south telescope to get spectra of those stars to determine how fast they were wizzing around the center of the globular cluster. they found that the stars move way faster than expected for the gravity created by the stars they see! this implies that there is some other source of large mass in the center that doesnt produce any light, but causes the stars near it to move really really fast!
this is super exciting for many reasons! omega centauri has been known to harbour some odd characteristics that the presence of a black hole helps explain, but this is also a long-looked-for intermediate-mass black hole! we've discovered many super massive black holes (ten million times the mass of our sun) at the centers of galaxies, and we know of many stellar mass black holes that result from the deaths of a big stars (about 10 times the mass of our sun), but this is only the second black hole ever found with a mass somewhere in between! how exciting!
you can listen to eva speak of her discovery herself on this nice hubble cast video!
as i did when another former fellow grad student, robert quimby, discovered something super cool in our universe, i'll share a few memories of eva!
she's known for her rockin' parties, impeccable taste in both film and music, and always having great halloween costumes!
when she first moved to germany in the fall of 2006, i was there for 4 months as well, so we enjoyed exploring munich together.... including oktoberfest!
we drove to vienna that fall for a beautiful wedding of two other astronomers...
and i was lucky enough to be invited to and able to attend her wonderful wedding in mexico!
ok, i guess i'll stop with all the gushing now... oh but wait, one more thing. since i mentioned oktoberfest... watch closely ;)