(ORDO NEWS) — It is widely believed that, with the exception of large celestial objects such as planets, stars, and asteroids, outer space is empty.
In fact, galaxies are filled with the interstellar medium (ISM) – gas and dust that permeate the space between these large objects.
It is important to note that under the right conditions, it is from it that new stars are formed.
Scientists from the University of California San Diego dedicated to their work using images from advanced telescopes as part of the JWST Cycle 1 Treasury program.
“With JWST, you can create incredible, very high-resolution maps of nearby galaxies that provide amazingly detailed images of the interstellar medium,” said Associate Professor of Physics Karin Sandström, one of the project’s principal investigators.
The galaxies that the Sandstrom group studied are relatively close, about 30 million light-years away.
The researchers focused on a specific component of the interstellar medium – polycyclic aromatic hydrocarbons (PAHs).
PAHs are small dust particles about the size of a molecule, and it is their small size that makes them so valuable to researchers.
When PAHs absorb a photon from a star, they vibrate. This usually does not happen with larger particles.
The vibrational properties of PAHs allow researchers to observe many important characteristics, including size, ionization, and structure.
Although PAHs do not make up a large fraction of the total ISM by mass, they are important because they are easily ionized, a process that can produce photoelectrons that heat the rest of the gas in the ISM.
A better understanding of PAHs will lead to a better understanding of the physics of the ISM. Astrophysicists hope that the JWST will help provide insight into how PAHs form, change, and break down.
Previous maps contained much less detail – in fact, they looked like galactic clumps.
With the clarity provided by JWST, astrophysicists can now see the gaseous filaments and even “bubbles” blown out by newborn stars.
The Cycle 1 Treasury program is part of a larger project called PHANGS (High Angular Resolution Physics in Nearby Galaxies).
PHANGS is studying star formation and the ISM using multiwavelength images from ALMA and the VLT in Chile.
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