Baby boom of galaxies

Last October, there was intense discussion about the reliable detection of the first galaxy in the reionization era, at redshift z=8.6. This means that we see the galaxy as it was when the Universe was approximately 600 million years old. What about more distant galaxies? They are constantly being searched for and from time to time they report the discovery of galaxy candidates at redshifts of about 10 (this corresponds to approximately 450 million years after the expansion of the Universe began). But so far these results have not been reliable enough.

An article by Bouwens et al. has appeared in the latest issue of Nature , which describes a new candidate at a redshift of about 10. Unfortunately, a good spectrum has not yet been obtained for the object. The authors themselves believe that this will require the launch of the James Webb Space Telescope, and this will only be in a few years. However, the candidate is good.

But this is not the main conclusion of the article. The main thing is that, having also discovered several candidate galaxies at redshifts around 7-8, the authors have reason to claim that from z=10 to z=8 rapid galaxy formation occurred. Otherwise, based on the number of candidates for z = 7-8, one would expect more candidates for z about 10. But there are none yet. This means that we managed to capture the period when galaxies are rapidly forming. In just 150-200 million years, many “newborn” galaxies appear.

Sergey Popov