The first of its kind to study tiny dust molecule in the nuclear region of active galaxies is being conducted by Oxford University. One of the biggest challenges in astronomy is understanding how galaxies form and evolve.
Polycyclic aromatic hydrocarbons, also known as PAHs, are one of the most widespread organic compounds in the universe. They may have played a key role in the origin of life. Astronomers can use the emission bands produced by PAH molecule when they are illuminated by stars to trace star formation activity, as well as to use them as sensitive barometers of the local physical conditions.
For the first time, the PAH properties in the nuclear region of three Luminous active galaxies have been characterized using cutting-edge instruments. The study was based on the data from the MIRI which measures light in the 5–28 micron wavelength range. The observations were compared with theoretical predictions.
Previous studies had predicted that the PAH molecule would be destroyed in the vicinity of the black hole. The analysis showed that PAH molecule can survive in this region, even if they are ripped apart. There is a chance that the molecule are protected by large amounts of gas.
The results showed that the black holes at the center of the galaxies had an impact on the properties of PAH molecule. The proportion of larger and neutral molecule went up, indicating that PAH molecule may have been destroyed. The PAH molecule can't be used to probe how quickly an active galaxy makes new stars.
The research is of interest to the wider astronomy community, especially those focused on the formation of planets and stars in the most distant and faint galaxies. We can observe PAH molecule in the nuclear region of a galaxy and the next step is to analyze a larger sample of active galaxies with different properties. We will be able to better understand how PAH molecule survive in the nuclear region. PAHs can be used as an accurate tool for estimating the amount of star formation in the universe.
The study is in astronomy and astrophysics.
More information: I. García-Bernete et al, A high angular resolution view of the PAH emission in Seyfert galaxies using JWST/MRS data, Astronomy & Astrophysics (2022). DOI: 10.1051/0004-6361/202244806 Journal information: Astronomy & Astrophysics
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