For the first time, researchers have drawn up a map of the Magellan Crown, a rainbow of scattered gas that protects two Milky Way galaxies, based on Hubble and FUSE data.
With the help of Hubble and a satellite already out of service, Far Ultraviolet Spectroscopic Explorer, an astronomer team has been able to solve one of the great mysteries of Magellan Clouds, Milky Way galaxy satellites, which have been orbiting each other for billions of years and gravitationally drawn to our galaxy and torn apart, leaving behind a plume of gas and debris, but to the great surprise of the entire astronomical community, the Magellano Clouds have maintained their fruitful star-forming activity.
Thanks to data from Hubble and FUSE, researchers have finally realized that, more specifically, who is responsible: the Magellan system is surrounded by a crown, a shield of hot gas that envelops two galaxies; it, called the Magellan crown, prevents its absorption by Milky Way, allowing the Magellan clouds to continue to produce new stars.
Studying quasars to understand the Magellan Clouds
In search of direct evidence of the existence of the Magellan Crown, the team investigated the Hubble and FUSE archives for ultraviolet observations of quasars located in billions of light years behind it. Why quasars? Because they, the galaxy cores, which contain huge active black holes, are extremely bright, so the team assumed that since the crown is too weak to be seen directly, it can be seen as a kind of fog that conceals and absorbs part of the light from distant quasars.
The team was able to detect and characterize the material surrounding the Great Magellanovo Cloud and to confirm the existence of the crown. When the light of the quasar passes through the crown, some of the waves of the ultraviolet light are absorbed, so the quasar spectra are characterized by clear signs of carbon, oxygen and silicon that make up the gas of the crown.
In comparing the results, the team also found that the amount of gas was decreasing at a distance from the center of the Greater Magellan Cloud. ", said Krishnaro. "
Gas curtain protecting galaxies
How can such a thin gas curtain protect the galaxy from destruction? This is because everything that's trying to get close to the galaxy must first pass through this material, which absorbs part of it in a collision. That's why it's called a shield. Researchers believe that the crown acts as a kind of "buffer" to protect the star-forming gas of dwarf galaxies from the gravitational gravity of a much larger Milky Way.
This diffuse hot gas eagle surrounding the Small and Grand Magellano Clouds, first and fully mapped, extends over 100,000 light years from the major mass of stars, gas and dust that make up the Magellano Clouds, blending with a hotter and larger crown surrounding the Milky Way.
This behavior is very similar to that of the crown surrounding the galaxy of Andromeda, which was also displayed in the past by distant quasars. A huge halo consists of a very diluted and ionized gas that does not emit easily detectable radiation. Therefore, tracking the absorption of light from a background source such as Quazara is the best way to study this material. The study was also conducted on the Hubble archive.
Implications for galactic evolution
The existence of the crown around the Magellan Clouds was predicted a few years ago, but has not yet been observed. In fact, although it extends more than 100,000 light years from two dwarf galaxies and occupys a large part of the southern sky, it is virtually invisible. The integrated mapping provided by scientists in this study required 30 years of archival data analysis to produce adequate measurements.
This discovery involves a new aspect of the evolution of galaxies: they are wrapped in gaseous cocoons that act as shields against other galaxies in their surroundings. Researchers believe that these cocoons, or cocoons, are the remnants of a primordial cloud of gas that collapsed by forming a galaxy. Although the crowns have been seen around more remote dwarf galaxies, astronomers have never been able to explore them as thoroughly as this one. And since they are so close, the Magellano Clouds offer an ideal opportunity to study the interaction and evolution of dwarf galaxies.