X-ray: NASA/CXC/SAO/G. Ogrean et al.; Optical: NASA/STScI; Radio: NSF/NRAO/VLA
Astronomers at the University of Texas and the Space Telescope Science Institute have devised a way to clear visual noise from satellite images, revealing a glimpse of our universe in its infancy. They shared their findings on the preprint server arXiv.
The current hypothesis about our universe’s early days goes something like this: In the beginning, there was the Big Bang, with all its attendant spark and electrical charge. Some time after that, all went dark. Then the first galaxies bloomed, bringing with them clouds of energy that re-ionized and lit up the sky. Lovely as this story sounds, it’s been difficult to prove, as these old, old, old galaxies have long since grown pale and indistinct amidst the bright chaos of newer celestial goings-on.
Lead author Rachael C. Livermore and her colleagues figured that if they could dim or shut out some of that newer radiance, they might stand a chance of finding the ancient galaxies.
Their solution: a technique called wavelet decomposition, which can mask high-volume brightness the same way noise-canceling headphones shut out sound.
“The wavelet transform allows us to decompose an image into its components on different physical scales,” the authors wrote. “Thus, we can isolate structures on large scales … and remove them, allowing objects on smaller scales to be identified more easily.”
They applied this new method to Hubble telescope images of star clusters Abell 2744 and MACS 0416. And it worked like a charm. Selectively turning down the brightness revealed 167 never-before-seen galaxies, all quite elderly and faint.
The authors say their discovery provides “strong support” for the theory of re-ionization. They and other astronomers will have boatloads of new images to examine quite soon, as the James Webb Space Telescope is scheduled to launch in 2018.