Abell 2256 at Optical Wavelengths (Image Credit: Bob Franke (Focal Pointe Observatory)
Galaxy clusters are indeed among the most immense structures in the universe—with so much mass, they warp spacetime to such a degree that they turn into
massive magnification lenses. What they don't tell you, however, is just how mysterious and counter-intuitive they often are. Many of the mysteries boil down to
how stars form within them, but now, new mysteries have surfaced.
Using the Karl G. Jansky Very Large Array (VLA), a team of researchers from the National Radio Astronomy Observatory (NRAO) have honed in on a perplexing region of space known to house a galaxy cluster in which hundreds of galaxies are entrenched in chaos, they ultimately provided the clearest picture yet of the surrounding environment.
The cluster, called
Abell 2256, can be found about 800 million light-years from Earth in the Ursa Major constellation. It spans around 4 million light-years across, which makes it quite large by any standards, but its size is not what sets it apart. Rather, the fact that these galaxies are colliding at such rapid speeds do.
After a lengthy upgrade, the
VLA's extended capabilities (with a new name) allowed the researchers to compile a true-color image of its radio emission.
Image Credit: Owen et al., NRAO/AUI/NSF
According to the team, "This image shows the region as it would appear if human eyes were sensitive to radio waves instead of light waves. In this image, red shows where longer radio waves predominate, and blue shows where shorter radio waves predominate, following the pattern we see in visible light."
While it may look straightforward enough on the surface, there are many puzzling aspects that present themselves only at the radio portion of the electromagnetic spectrum, mostly pertaining to the ongoing collisions—features that are referred to as halos, long tails and large relics. They aren't new per se, but as Frazer Owen, one of the NRAO researchers involved in this study, describes, "The image reveals details of the interactions between the two merging clusters and suggests that previously unexpected physical processes are at work in such encounters,"
At the end of the day, these features remain enigmatic, but with this new insight, and some more observational time, perhaps we'll soon know what we're dealing with.
Overall, the above image of Abell 2256 takes up an area of sky roughly equivalent to that of the full moon. (
The full press release can be found here.)
댓글 없음:
댓글 쓰기