The Sombrero galaxy likely merged with a relatively massive galaxy several billions of years ago. In a new study published in the Monthly Notices of the Royal Astronomical Society, astronomers analyzed wide-field deep images of the Sombrero galaxyâs outskirts obtained with a small amateur telescope with the purpose of detecting any tidal structures â such as stellar streams and tails â from the possible ancient merger.
The Sombrero galaxy is located approximately 28 million light-years away in the constellation of Virgo. Also known as Messier 104, M104 or NGC 4594, the galaxy was discovered on May 11, 1781, by the French astronomer Pierre MÊchain. It has a diameter of approximately 49,000 light-years, about 3 times smaller than our Milky Way Galaxy.âThe Sombrero galaxy shows characteristics of both of the dominant types of galaxies in the Universe, the spirals and the ellipticals,â said Dr. David MartÃnez-Delgado, an astronomer at the Instituto de AstrofÃsica de AndalucÃa â CSIC, and his colleagues.âIt has spiral arms, and a very large bright central bulge, which makes it look like a hybrid of the two types.â
The recent discovery of extremely metal-rich stars in the halo of the Sombrero galaxy suggested that the galaxy had undergone a recent major merger with a relatively massive galaxy.âAccording to the latest cosmological models, large spiral galaxies such as the Milky Way grew by absorbing smaller galaxies, by a sort of galactic cannibalism,â the astronomers said.âEvidence for this is given by very large structures, the tidal stellar streams, which are observed around them, which are the remains of these satellite galaxies.âBut the full histories of the majority of these cases are hard to study, because these flows of stars are very faint, and only the remains of the most recent mergers have been detected.â
An artistâs impression of the tidal stream around the Sombrero galaxy. Image credit: Jon Lomberg / Stellar Tidal Stream Survey.
In the new study, the researchers observed the ring-like tidal structure in the inner halo region of the Sombrero galaxy.âIt is remarkable that thanks to these advanced photometric techniques we have been able to do front line science with a Messier object using only an 18-cm-diameter telescope,â said co-author Dr. Javier RomÃĄn, a postdoctoral researcher in the Instituto de AstrofÃsica de AndalucÃa â CSIC, the Instituto de AstrofÃsica de Canarias, and the Universidad de La Laguna.
The teamâs result is in agreement with the hypothesis that the galaxy was created by a âwet major mergerâ event more than 3.5 billion years ago that heated up the stellar population.âA âwet mergerâ is a scenario in which a large elliptical galaxy is rejuvenated by large quantities of gas and dust from another massive galaxy, which went into the formation of the disk which we now observe,â they said.âIn our search, we have been able to trace for the first time the complete tidal stream which surrounds the disk of the Sombrero galaxy and our theoretical simulations have let us reconstruct its formation in the last 3 billion years, by cannibalism of a satellite dwarf galaxy.â
Source: sci-news.com
The Sombrero galaxy is located approximately 28 million light-years away in the constellation of Virgo. Also known as Messier 104, M104 or NGC 4594, the galaxy was discovered on May 11, 1781, by the French astronomer Pierre MÊchain. It has a diameter of approximately 49,000 light-years, about 3 times smaller than our Milky Way Galaxy.âThe Sombrero galaxy shows characteristics of both of the dominant types of galaxies in the Universe, the spirals and the ellipticals,â said Dr. David MartÃnez-Delgado, an astronomer at the Instituto de AstrofÃsica de AndalucÃa â CSIC, and his colleagues.âIt has spiral arms, and a very large bright central bulge, which makes it look like a hybrid of the two types.â
The recent discovery of extremely metal-rich stars in the halo of the Sombrero galaxy suggested that the galaxy had undergone a recent major merger with a relatively massive galaxy.âAccording to the latest cosmological models, large spiral galaxies such as the Milky Way grew by absorbing smaller galaxies, by a sort of galactic cannibalism,â the astronomers said.âEvidence for this is given by very large structures, the tidal stellar streams, which are observed around them, which are the remains of these satellite galaxies.âBut the full histories of the majority of these cases are hard to study, because these flows of stars are very faint, and only the remains of the most recent mergers have been detected.â
An artistâs impression of the tidal stream around the Sombrero galaxy. Image credit: Jon Lomberg / Stellar Tidal Stream Survey.
In the new study, the researchers observed the ring-like tidal structure in the inner halo region of the Sombrero galaxy.âIt is remarkable that thanks to these advanced photometric techniques we have been able to do front line science with a Messier object using only an 18-cm-diameter telescope,â said co-author Dr. Javier RomÃĄn, a postdoctoral researcher in the Instituto de AstrofÃsica de AndalucÃa â CSIC, the Instituto de AstrofÃsica de Canarias, and the Universidad de La Laguna.
The teamâs result is in agreement with the hypothesis that the galaxy was created by a âwet major mergerâ event more than 3.5 billion years ago that heated up the stellar population.âA âwet mergerâ is a scenario in which a large elliptical galaxy is rejuvenated by large quantities of gas and dust from another massive galaxy, which went into the formation of the disk which we now observe,â they said.âIn our search, we have been able to trace for the first time the complete tidal stream which surrounds the disk of the Sombrero galaxy and our theoretical simulations have let us reconstruct its formation in the last 3 billion years, by cannibalism of a satellite dwarf galaxy.â
Source: sci-news.com
