Dyears the first image deep field beautifully detailed télescope spatial James Webb (Webb) released in June this year (image above, click to enlarge), you can see hosts of some of the oldest galaxies in the universe, sparkling like diamonds in the vast expanse of space and time…
In June 2022:
Looking deeper into the image, a Canadian research team has now discovered the globular clusters the most distant ones identified to date, which might contain the first and oldest stars in the universe. Finding these clusters is a task for which the Webb was specially designed.
According to Lamiya Mowla, a fellow at the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto (Canada) and co-lead author of the study:
Webb was built to find the first stars and galaxies and to help us understand the origins of the complexities of the universe, such as the chemical elements and the building blocks of life.
The researchers focused on a galaxy dubbed the “Sparkling Galaxy” (Sparkler Galaxy), due to the small, shimmering yellow and red dots of star clusters surrounding it. Five of the twelve “flickers” analyzed turned out to be globular clusters, which are typically found in the bulge and halo around galaxies and contain many old, red stars. Since they are very close to each other, these clusters are usually very stable and last for billions of years.
This discovery was made by the aptly named CANUCS for Canadian NIRISS Unbiased Cluster Survey.
The globular clusters were identified by the CANUCS team due to the absence of spectral lines of oxygen in the spectro-imager data NIRISS (Near-Infrared Imager and Slitless Spectrograph) you Webb.
Location of the Sparkler galaxy in the Webb’s first deep-field image. Top left, comparison with Hubble images and zoom, bottom left, on a globular cluster. (NASA/ ESA/ L. Calçada)
The presence of oxygen is important. If detected, it would suggest that the clusters were much younger and actively engaged in star formation.
The incredible resolution and sensitivity of the Webb (as well as a happy natural magnification due to the effect of gravitational lens of a galaxy in the foreground) made it possible to observe these “sparks” for the first time, which the instruments of Hubble (the Webb’s predecessor) might never have done. Thanks to multi-wavelength observations of the clusters, scientists can better model and understand their physical properties, such as their age and the number of stars they contain.
This illustration shows a phenomenon known as gravitational lensing, which is used by astronomers to study very distant, very faint galaxies. (NASA/ ESA/ L. Calçada)
For globular clusters so distant and so old, this represents the chance to glimpse the “bestiary” of the very old universe.
Still according to Mowla:
These newly identified clusters formed close to when it was possible to form stars for the first time. Since the Sparkler galaxy is much further away than our Milky Way, it is easier to determine the age of its globular clusters. We observe the Sparkler as it was 9 billion years ago, when the universe was only 4.5 billion years old.
As the Webb gazes into space, we can expect to learn more regarding the origins of our universe, and ultimately regarding ourselves.
The study published in The Astrophysical Journal Letters: The Sparkler: Evolved High-redshift Globular Cluster Candidates Captured by JWST and presented on the University of Toronto website: Dunlap researchers help reveal a galaxy sparkling with the universe’s oldest star clusters.
