Spanish researchers from the Instituto de Astrofísica de Andalucía (IAA-CSIC) and the Instituto de Astrofísica de Canarias (IAC) have made an important advance in understanding the characteristics of the Sombrero galaxy, by observing in detail a gigantic current of stars that compose it.
The Sombrero galaxy (M104) is located about 30 million light years from Earth, forming part of the Local Supercluster, which includes the Virgo cluster and the so-called Local Group, in which the Milky Way is located. It is strange in itself, since it has characteristics of spiral and elliptical galaxies, becoming a kind of hybrid of both.
With an approximate mass of 800,000 million suns , M104 is moving away from Earth at a speed of 1,000 kilometers per second, a phenomenon caused by the constant expansion of the universe in multiple directions. It was discovered by the French astronomer and geographer Pierre Méchain, on May 6, 1783.
A SPIRAL, ELLIPTICAL, OR HYBRID GALAXY?
Although its structure cannot be seen with the naked eye from Earth, it can be easily observed with simple telescopes. Despite having been initially classified as a spiral galaxy, there are theories that maintain that it would actually be a large elliptical galaxy .
According to these postulates, approximately 9,000 million years ago the Sombrero Galaxy would have captured cosmic material forming a disk inserted in its structure, which would later have evolved to obtain its current shape.
The new study, published in the Monthly Notices of the Royal Astronomical Society (MNRAS), has managed to obtain unique details of a large tidal stream or stream of stars in this galaxy, which could partly explain its strange morphology, which remains without have a definitive and concrete explanation.
WET FUSION AND A STRANGE HALO
According to a press release , the stellar stream would have originated from the absorption of a smaller galaxy in the last 3,000 million years. The discovery leaves open the possibility that the strange shape of the Sombrero galaxy is due to a ” wet merger, ” a scenario in which a large elliptical galaxy is “rejuvenated” by large amounts of gas and dust from another massive galaxy. .
That hypothetical collision was suggested from recent observations by the Hubble Space Telescope, which studied the stellar population of the large galactic halo that surrounds M104. Although the discovery of the Spanish astrophysicists does not confirm this theory, it leaves open the possibility for future research that can elucidate the enigma.
Galactic halos are believed to be made up of low-density interstellar gas, old stars, and dark matter. However, the mystery about the Sombrero galaxy increases if we take into account that a large number of metal-rich stars have been found in its halo, an aspect that would indicate that they are young stars .
As the stars of recent generations are usually located in the disks of galaxies but very unusually in the galactic halos, M104 has become a complex, unclassifiable galaxy that poses strong challenges to scientists. Will the new Spanish study be the key to solving the unknowns posed by the Sombrero galaxy?