I Love Gravitational Lensing

Perhaps love is too strong a word, how about respect, admire, like it-like it, we're just good friends? Naw, screw it! I LOVE Gravitational Lensing. Ever since I was introduced to the concept in my astro days, and then was a paid seeker of any such events, I have loved the idea of using gravitational lensing as a research tool. I was paid to find gravitational lensing events for a cosmology group at Berkeley so we could find the "furthest" galaxy, because lensing magnified the light, actually letting us see objects that would normally be dim. My advisor had held the record, but was beaten by another observer, and was competitively searching for the next record. Lensing was also used to figure out how much dark matter was screwing around with galaxy clusters, which was also very cool. But this idea, to use lensing to detect the dark matter itself, is genius!

 

Image courtesy of NASA / CXC / CfA / STScI / Magellan / Univ. of Ariz. / ESO

 

In the false color composite image above, the blue gas in the collision of two galaxy clusters is the dark matter. The magenta colored gas is the actual visible gas. The color scale corresponds to the gradient of the gravitational field calculated from the lensing of the background galaxies. Awesome! This is the first experiment to verify the hypothesis that dark matter does not interact directly with regular matter, otherwise the dark matter gas would have behaved the same as the visible gas. Perhaps dark matter is more WIMPy (Weakly Interacting Massive Particles) than MACHO (MAssive Compact Halo Objects). Read the whole article.