James Webb Space Telescope discovers organic molecules in distant galaxies

(ORDO NEWS) — Oxford scientists conducted the first study of molecules in distant galaxies using the James Webb Space Telescope. The study will help understand how galaxies form and develop.

Polycyclic aromatic hydrocarbons (PAHs) are among the most abundant organic molecules in the universe and an important astronomical tool that helps determine star formation activity in a galaxy.

They are considered the basic building blocks of prebiotic compounds, possibly playing a key role in the origin of life.

Opening details

PAH molecules produce very bright infrared radiation when illuminated by stars. This allows astronomers to not only track star formation activity, but use them as markers of local physical conditions.

The new study characterizes the properties of PAHs in the central (nuclear) region of three active galaxies for the first time.

The work was based on spectroscopic data from the MIRI instrument, which measures light in the 5-28 micron wavelength range.

The researchers compared the observation to theoretical predictions for PAH molecules and were surprised when the results disproved them.

The calculations assumed the destruction of PAHs near the black hole in the center of the galaxy.

However, the analysis showed that molecules can survive in this region of space, even where very energetic photons can tear them apart.

A possible reason is that the molecules are protected by a large amount of molecular gas.

It is incredible to think that we can observe PAH molecules in the nuclear region of the galaxy. The next step will be to analyze a larger sample of galaxies with different properties.

Such knowledge is key to using PAHs as an accurate tool to characterize the amount of star formation in galaxies and therefore understand how galaxies evolve over time, said Dr. Ismael Garcia-Bernete, who led the study.

Where PAH molecules survived, the results showed that supermassive black holes at the heart of galaxies had a significant impact on their properties.

In particular, the proportion of large and neutral molecules became larger, indicating that the more fragile small and charged PAH molecules could be destroyed.

This imposes some restrictions on the use of these PAH molecules to study how quickly an active galaxy forms new stars, but does not completely discard the method.

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