Thanks to NASA’s James Webb Space Telescope, which was built precisely to detect the faint infrared light from extremely distant galaxies, astronomers can now see a glimpse of the early cosmos. Galaxies at this early period are not well known or understood today.
However, gravitational lensing brought about by a collection of galaxies in the foreground can enhance the visibility of weak background galaxies and make them appear brighter multiple times in different parts of the image.
Related: NASA’s James Webb Telescope Captures Extreme View of Merging Galaxies
We’re here today to talk about the most recent work of three astronomers working on the Webb telescope. Tiger Hsiao from Johns Hopkins University, Rebecca Larson from the University of Texas at Austin, and Dan Coe from AURA/STScI for the European Space Agency and Johns Hopkins University make up the team. These astronomers have been using Webb to study the distant galaxy MACS0647-JD, and they have made an exciting finding.
Daniel Coe: I discovered the galaxy MACS0647-JD ten years ago using the Hubble Space Telescope. I had never worked on high redshift galaxies before I came upon this galaxy, which was maybe the most distant at redshift 11, or 97 percent of the way back to the big bang. It was the only red dot Hubble could make out.
In the first 400 million years of the universe, it was merely a little galaxy, yet even then, we could see that it was exceedingly small. Webb is now glancing, so we can resolve TWO objects! There is a lot of debate about whether these are two galaxies or two star clusters within a galaxy. We don’t have the answers to these questions, so Webb is here to assist us.
Tiger Yu-Yang Hsiao: The stark contrast between the two objects’ colours is also obvious. While the other is more red, the first is more blue. The red gas and the blue gas have different properties. The blue object actually has extremely early star formation and essentially little dust, whereas the small, red object is older and has more dust. Furthermore, they probably have differing stellar masses.
It’s really interesting that there are two structures in such a small system. A galaxy merger may be taking place right now in the early universe. If this is the farthest merge, I’ll be over the moon!
Daniel Coe: Three images, JD1, JD2, and JD3, are created by gravitationally lensing the massive galaxy cluster MACS0647. Each of these is multiplied by 8, 5, and 2, correspondingly.
Becky Larson: Up until now, we have not been able to analyse galaxies in the early universe in great detail. We only had a few tens of them before Webb. By examining them to see how they changed to resemble the galaxy we currently live in, we can discover more about their evolution. Moreover, the evolution of the universe.
The fact that galaxies may be seen as tiny dots in the background of so many of the new Webb images that we receive is, in my opinion, my best feature. Each and every one of them. Previously unseen to us, we are now receiving a staggering amount of information.
The field isn’t particularly deep either. There wasn’t much exposure time. Since a very long time ago, we haven’t even attempted to use this telescope to focus on a single object. This is only the start!