Image of candidate galaxy CEERS-93316. / Sophie Jewell, Clara Pollock
The James Webb Space Telescope has detected another candidate for the oldest galaxy on record…until now. CEERS 93316, would be the set of massive stars that existed when the universe was only 250 million years old. The survey is available on the pre-publication site arXiv.
Over the past decade, astronomers have made great strides in studying the evolution of galaxies in the universe. For example, they discovered systems with a cosmological redshift value of z of almost 11.
The results of James Webb’s observations should seriously expand and complement current cosmological concepts. According to many scientists, the telescope could reveal objects up to z=20.
In particular, the observatory has already found two record candidates for distant galaxies at z=13–15. This is important in determining when the reionization epoch begins, when the population of the first galaxies was able to reionize hydrogen in the interstellar and intergalactic medium.
Work
Now, a group of astronomers from the University of Edinburgh announced the discovery of another candidate for the most distant known galaxy. This achievement was achieved during the search and study of galaxies in the redshift range z=8−15 en Deep-sky photometric data observed by James Webb’s NIRCam instrument.
In addition, the COSMOS field was used, as part of the UltraVISTA ground survey, and the Spitzer Space Telescope. In total, the sample used for analysis contained 55 high redshift galaxies, 44 of which are new.
In the work, the scientists used the method of leap lyman. It is that a photon characterized by a wavelength less than 91.2 nanometers will be completely absorbed by hydrogen gas both in the distant galaxy observed and in the line of sight of the terrestrial observer.
Therefore, a break in the spectrum of the galaxy will be observed. By using sets of filters operating at different wavelengths, one can search for galaxies at different redshifts.
The Galaxy
The photometric redshift of CEERS 93316 was z = 16.6 ± 0.1. In other words, when the universe was around 250 million years old. Being a rather unusual result, the authors tested other plausible explanations.
CEERS 93316 is relatively large, with an estimated stellar mass of 109 solar masses. The rate of star formation in the galaxy is estimated at 101.1 solar masses per year.
On another side, the process of star formation began in the galaxy between 120 and 220 million years ago after the big Bang (z = 18−26). However, the researchers found no evidence that the system has an unusual stellar population (with a predominance of stellar population III).
If CEERS-93316 is a galaxy, it probably won’t be the most distant galaxy in history for long. Although CEERS-93316 does not turn out to be a galaxy so far awaythere is no doubt that the Webb will show us another object which is soon.