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Seminar by Vladimir YershovState University from Aerospace Instrumentation, St. Petersburg

  • January 10th, 2025
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Title: Cosmological interpretation of the JWST observations

Place: Seminar del DAA. Jeroni Muñoz Research Building, fourth floor, in Burjassot.

Day: Monday, january 13 , 2025. Time: 12:00.

Abstract:

One of the main tasks for which the James Webb Space Telescope (JWST) was designed is to peer into the epoch of the supposed birth of the first stars (hypothetical Population III stars) and the formation of the first galaxies, which corresponds to the end of the Dark Ages, when there were no stars.  According to the standard cosmological model (LCDM), this epoch is 200-250 million years away from the beginning of the expansion of the Universe (redshift z =17--20).
The two main design parameters of the JWST telescope (its large aperture of 6.5 m and the ability to operate in the IR range up to a wavelength of 25 μm) make this telescope ideal for observational testing of cosmological models  (the structure of the Universe, the nature of the redshift, the nature of the cosmic microwave background, etc.), and cosmogony (the formation and development of stars and galaxies). The very first JWST observations, published in 2022, showed that for redshifts corresponding to the age of the Universe of 250-600 million years, the predictions of the standard cosmological model are very different from reality. First, it turned out that there are a very large number of massive galaxies in the early Universe (with masses $>10^{10}$\,M$_\odot$) that formed less than 700 million years after the beginning of the universe. The observed large number density of massive galaxies with $z>10$ is at odds with the predictions of the theory of galaxy formation. 

These observational facts are currently explained by galaxy evolution. But there is a problem here, because the JWST observations show that galaxies with z>10 are fully formed, with disks and bulges, containing large amounts of dust and heavy chemical elements. They are look-alikes of the late-universe galaxies, but with one exception: the physical sizes of remote galaxies are much smaller than those of the galaxies next to us.

Imagine a 10 cm toy car that weighs 3-4 tons and has the full functionality of a real car. This is what galaxies discovered by the JWST telescope look like.
This report presents the results of a cosmological test of the dependence of the angular size of galaxies on their redshift. The test was performed on the basis of JWST observations. It is shown that for the correct interpretation of these observations, an alternative explanation of the cosmological redshift of the observation is required. 

In this alternative interpretation, the JWST observations correspond to galaxies with quite normal sizes. At the end of the report, an interpretation of the cosmological redshift is presented, according to which the observational data of Type Ia supernovae are approximated more accurately than when using the parameters of the standard cosmological model.