Researchers use the James Webb Space Telescope to view growing “baby galaxy”

Answering the question of how galaxies form and grow over time has been a driving reason for the construction of the James Webb Space Telescope (JWST).

Now, a team of researchers led by PhD student Yoshi Asada and Dr. Marcin Sawicki at Saint Mary’s University made an exciting discovery using the JWST that will help explain the structure of the Universe. They discovered a “baby galaxy” that is being assembled from “building blocks” created early in the history of the Universe. This galaxy is a perfect example of a galaxy in its early stages of growth, and its study will help scientists better understand this crucial part of a galaxy’s life. The galaxy is the result of a collision and ongoing merger of two smaller galaxies named ELG1 and ELG2. The remnants of these two smaller galaxies can still be seen in the JWST images.

The discovery of this baby galaxy is particularly exciting because the JWST images studied by the astronomers have been highly magnified by a phenomenon called Einstein’s gravitational lensing effect. Due to the presence of other massive galaxies between the telescope and the target baby galaxy, which act as a cosmic magnifying glass, the baby galaxy’s light has been warped.

There’s an upside, notes NSERC-funded researcher Dr. Sawicki, Canada Research Chair and Professor of Astronomy and Physics at Saint Mary’s University. “Because of Einstein’s lensing effect, we see the galaxy twice in two slightly different places in the sky. It’s like seeing a mirage in the desert―we see the same image twice because light takes two different paths to reach our eye.” The galaxy’s light also appears up to 15 times brighter, making it easier to observe and study.

The images of the baby galaxy were taken earlier this year using the Near Infrared Camera Instrument aboard the JWST, which was launched in December 2021. The astronomers’ study of this system was published recently in the peer-reviewed journal Monthly Notices of the Royal Astronomical Society.

Combining the power of the JWST and gravitational lensing has allowed the astronomers to get an intensely close look at this baby galaxy. “Studying this object has allowed us to gain some important insights about how young galaxies form. We learned that they get built from the merging of smaller sub-components and that during their assembly, the galaxies can undergo intense growth spurts of star formation”, explains Asada, a Kyoto University PhD student who is the lead author of the study and who is spending a year in Canada working on the JWST data with Canadian astronomers.

Both Asada and Sawicki are members of the CANUCS collaboration, which uses the power of the JWST boosted by Einstein’s gravitational lensing to study the details of some of the smallest, youngest, and most distant galaxies in the Universe. “The combination of JWST and gravitational lensing is letting us get a glimpse of the early Universe that was not possible until now. With our JWST CANUCS observations in hand, we look forward to many more discoveries about how galaxies such as our own Milky Way grew over cosmic time,” adds Dr. Sawicki.

This article was adapted and published with permission from Saint Mary’s University.