Multiple-Intelligences Neural Interfacing Optimization Node
I'm a geek. No. Really. Really geeky. And I write poetry. And I read poetry. I'm an English teacher to-be.
(via APOD: 2013 January 2)
The Einstein Cross Gravitational Lens
Image Credit & Copyright: J. Rhoads (Arizona State U.) et al., WIYN, AURA, NOAO, NSF
What happens when a bright quasar is situated right behind the massive nucleus of a foreground galaxy? A duplication effect is created as light from the quasar is bent by relativistic gravitational lensing, creating an Einstein Cross. The relative position and brightness of the quasar can be changed by the mass distribution in the galaxy, even creating delays of entire days as the light moves around.
This example of light being lensed around a massive elliptical galaxy comes from the Subaru Telescope:
PG 1115+080: A Gravitational Cloverleaf
Credit: CISCO, Subaru 8.3-m Telescope, NAOJ
In the case of the Einstein Cross here, though, the galaxy is a spiral, and, interestingly, the intervening dust in the galaxy itself does not significantly shift the light of the quasar through scattering. Amusingly, this configuration was noted because a sky survey found a low redshift galaxy whose nucleus seemed to be exactly like that of a high redshift quasar - based on the spectroscopy. Also of interest, the individual stars in the galaxy can create noticeable shifts in the brightness of the quasar through microlensing effects. Overall, they are much smaller than the effect of the whole galaxy, but they do create fluctuations that can be detected.
(via Gravitational lens reveals details of distant, ancient galaxy | UChicago News)
I’ve been wondering when someone would start to do this. Cosmologists at UChicago have taken VLT data, Hubble Wide-Field 3 data, and some serious computer modeling and optics/relativity reverse-engineering to use a galaxy cluster’s gravitational lensing effect as a telescope.
The reconstructed galaxy at the lower-left is based on the relativistic warping created by the foreground galaxy cluster on the circled warped and repeated images of the galaxy itself, which is actually behind the cluster.
(via APOD: 2011 December 21 - A Horseshoe Einstein Ring from Hubble)
Einstein’s famous reaction to quantum mechanics, “God does not play dice with the universe,” apparently doesn’t extend to horseshoes.
This image from Hubble shows a nearly perfect alignment of a luminous red galaxy in the foreground and a faint blue galaxy in the background. Usually, we see gravitational lensing as a distortion and repetition of the image of the background galaxy around the foreground one, but this is so well aligned that the one in the back is nearly warped into a complete circle around the red one in front. The effect is called an Einstein ring because his theory of general relativity predicted them over 70 years ago.
The Wide Field Camera 3 captured this shot and the lensing effect helps us understand how much mass and dark matter is in the foreground galaxy.
(via APOD: 2011 October 17 - MACS 1206: A Galaxy Cluster Gravitational Lens)
MACS 1206 is the one that Phil showed us earlier on Bad Astronomy, but I love this detail shot so much that I’m posting it again from APOD. The lensing effect that the cluster is having on the background galaxies allows us to determine how much dark matter is in the cluster and how it is distributed. It requires a certain amount of gravity to make the light from a background galaxy warp and lens a certain way, and by comparing the lensing to the the amount of visible mass in the image, scientists can calculate the dark matter distribution.
Image Credit: NASA, ESA, M. Postman (STScI), and the CLASH Team
(via Galaxies swarm and light bends under dark matter’s sway | Bad Astronomy | Discover Magazine)
Holy mother…4.5 billion light years away from us is a galaxy cluster (MACS J1206) with a mass 1 quadrillion times the mass of the Sun. And it’s bending light. It’s bending light more than it should based on what we can see. Conclusion? Dark matter. You can tell how much and where it is based on how the galaxies behind the cluster are bent and smeared. It’s called gravitational lensing and it’s really nifty looking.
Phil’s got a great write-up, and this is a Hubble shot from the CLASH project, which is getting an unprecedented 524 orbits with Hubble. That’s 300 hours of continuous viewing. The Hubble data will also be used by this team to point the ESO’s VLT telescope in Chile at various targets to get spectrometry readings.
Interesting structures Phil would like to point out to you in the shot:
Galaxy being lensed by the cluster and, it would appear, also by the other two galaxies that you can see.
Very red galaxies which may be very small members of the same cluster (dust in the way) or very old (red-shifted).
Image credit: Credit: NASA, ESA, M. Postman (STScI) and the CLASH Survey Team
(via APOD: 2011 September 15 - NGC 3521: Galaxy in a Bubble)
NGC 3521 is easily visible even in a small telescope, but tends to be overlooked for its neighbors in Leo, M65 and M66.
I think it’s lovely, especially the “bubbles” of tidal dust around it. They’re probably dust left over from when NGC 3521 absorbed various satellite galaxies in its past.
Of interest to me is the warping that appears to be happening to the small blue barred-spiral galaxy just to the right of NGC 3521 in this image. I can’t tell if the angle of the image is making it look that way, or if that’s a gravitational lensing effect of NGC 3521 being in the foreground.
