14 DAY TRIAL // Using the NASA infrared Spitzer Space Telescope, astronomers recently conducted a new series of observations on the Sombrero Galaxy, which is also known as M104 and NGC 4594. The study revealed that this cosmic structure does not abide by the standard classification of spiral galaxies.
The thing that puzzled experts upon investigating this structure is the fact that it has both a rotund and a slender disk. Usually, spiral galaxies feature either one, or the other. The Milky Way, for instance, has a slender disk circling it.
Spitzer data reveal that the Sombrero Galaxy has an elliptical disk on the outside, as well as a thin one embedded within its inner structure. This is the first cosmic structure observed to display these two characteristics at the same time.
Scientists hope to use these new data to figure out more details about how galaxies evolve. Despite thousands of studies conducted in this direction, astrophysicists still don't have a complete understanding of how this process works.
“The Sombrero is more complex than previously thought. The only way to understand all we know about this galaxy is to think of it as two galaxies, one inside the other,” says astronomer Dimitri Gadotti, the lead author of the new study.
He holds an appointment with the Chile-based European Southern Observatory (ESO). Details of the work the expert and his team conducted were published in the latest issue of the esteemed scientific journal Monthly Notices of the Royal Astronomical Society.
“Spitzer is helping to unravel secrets behind an object that has been imaged thousands of times. It is intriguing Spitzer can read the fossil record of events that occurred billions of years ago within this beautiful and archetypal galaxy,” adds Sean Carey.
The expert is based at the Spitzer Science Center (SSC), which the California Institute of Technology (Caltech), in Pasadena, manages for NASA Headquarters, in Washington DC. He says that the Sombrero Galaxy is located some 28 million light-years away, in the direction of the constellation Virgo.
Researchers say that the first scenario proposed to explain the galaxy's structure – that a thin-disk spiral galaxy was included in a larger, round-disk one – is impossible, since the merging process would have destroyed both disks.
Another option, they add, is that vast volumes of gas flowed into a massive elliptical galaxy about 9 billion years ago. The material came from the huge networks of gas clouds that permeated the Universe at the time.
As it flowed towards the core of the galaxy, the gas may have led to the formation of the flat disk.