Astronomers using the NASA/ESA/CSA James Webb Space Telescope discovered the central starburst of Messier 82 (M82, NGC 3034, or Cigar Galaxy), a starburst irregular galaxy 12 million light-years away in the constellation A new image of the area was taken. of Ursa Major.

Messier 82 is located approximately 12 million light years away. It can be seen high in the northern sky in spring, in the direction of Ursa Major in the north.

First discovered by German astronomer Johann Erath Bode in 1774, this galaxy is approximately 40,000 light-years in diameter.

Messier 82 is also called the Cigar Galaxy because of its elongated elliptical shape caused by the tilt of its star-like disk with respect to our line of sight.

This galaxy is famous for its unusually high rate of new star formation, with stars being born 10 times faster than the Milky Way.

Astronomer Alberto Borat and his colleagues at the University of Maryland led Webb's research. NIRCam (Near Infrared Camera) We will aim our instrument at the center of Messier 82 to closely observe the physical conditions that promote the formation of new stars.

“Messier 82 is thought to be the prototype of a starburst galaxy and has attracted a variety of observations over the years,” Borat said.

“Both the Spitzer Space Telescope and the Hubble Space Telescope have observed this target. With Webb's size and resolution, we can observe this star-forming galaxy and see all of this beautiful new detail.”

“Star formation remains a mystery because it is shrouded by a curtain of dust and gas, which poses an obstacle to observing this process.”

“Fortunately, Webb's ability to see into the infrared can help us navigate these ambiguous situations.”

“Furthermore, these NIRCam images of the center of the starburst were obtained using instrumental mode, which prevents very bright light sources from overwhelming the detector.”

“Even in this infrared image, dark brown dust tendrils are visible throughout Messier 82's bright white core, but Webb's NIRCam has revealed a level of detail that was historically hidden.”

“If you look closely toward the center, small green specks indicate areas of concentrated iron, most of which are supernova remnants.”

“The small red spots indicate regions where hydrogen molecules are illuminated by radiation from nearby young stars.”

“This image shows the Webb's force,” said Dr. Rebecca Levy, an astronomer at the University of Arizona.

“All the white dots in this image are stars or star clusters. We can start to distinguish between all of these small point sources, which will allow us to get an accurate count of all the star clusters in this galaxy. Masu.”

If you look at Messier 82 at slightly longer infrared wavelengths, you'll see clumpy tendrils, shown in red, extending up and down the galactic plane. These gaseous streamers are galactic winds blowing out from the starburst's center.

One of the research team's areas of focus was understanding how this galactic wind, caused by rapid star formation and subsequent supernovae, originates and affects the surrounding environment.

By resolving Messier 82's central region, astronomers were able to investigate where the winds originate and gain insight into how hot and cold components interact in the wind. .

Webb's NIRCam instrument was well-suited to tracking the structure of the galactic wind via radiation from sooty chemical molecules known as polycyclic aromatic hydrocarbons (PAHs).

PAHs can be thought of as very small dust particles that survive at low temperatures but are destroyed at high temperatures.

Much to the team's surprise, Webb's observations about PAH emissions highlight previously unknown fine structures in the galactic wind.

This emission, depicted as a red filament, moves away from the central region where the center of star formation is located.

Another unexpected finding was the similarity between the structure of the PAH emission and the structure of the hot ionized gas.

“It was unexpected that the release of PAHs resembled ionized gases,” Dr. Borat said.

“PAHs are not thought to survive very long when exposed to such strong radiation fields, so they are probably constantly being replenished.”

“This casts doubt on our theory and indicates the need for further investigation.”

team's paper will be published in astrophysical journal.

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Alberto D. Borat other. 2024. Observation of starbursts by JWST: Emission of polycyclic aromatic hydrocarbons at the root of the M 82 galactic wind. APJ, in press. arXiv: 2401.16648