Astronomers at the University of Chicago, MIT and elsewhere have used a massive cluster of galaxies as an X-ray magnifying glass to peer back in time, to nearly 9.4 billion years ago. In the process, they spotted a tiny dwarf galaxy in its very first, high-energy stages of star formation.
While this technique has been used to magnify objects at optical wavelengths, this is the first time scientists have leveraged it to zoom in on extreme, distant X-ray-emitting phenomena.
What they detected appears to be a blue speck of an infant galaxy, about 1/10,000 the size of our Milky Way, in the midst of churning out its first stars—supermassive, cosmically short-lived objects that emit high-energy X-rays, which appear at optical wavelengths in the form of a faint blue arc.
“It’s this little blue smudge, meaning it’s a very small galaxy that contains a lot of super-hot, very massive young stars that formed recently,” said Matthew Bayliss, a UChicago alum who is currently a research scientist in MIT’s Kavli Institute for Astrophysics and Space Research. “This galaxy is similar to the very first galaxies that formed in the universe…the kind of which no one has ever seen in X-ray in the distant universe before.”
Image courtesy of HST GO15315.