Sombrero Galaxy Has Split Personality
ScienceDaily (Apr. 24, 2012) — While some galaxies are rotund and others are slender disks like our spiral Milky Way, new observations from NASA’s Spitzer Space Telescope show that the Sombrero galaxy is both. The galaxy, which is a round elliptical galaxy with a thin disk embedded inside, is one of the first known to exhibit characteristics of the two different types. The findings will lead to a better understanding of galaxy evolution, a topic still poorly understood.
“The Sombrero is more complex than previously thought,” said Dimitri Gadotti of the European Southern Observatory in Chile and lead author of a new paper on the findings appearing in the Monthly Notices of the Royal Astronomical Society. “The only way to understand all we know about this galaxy is to think of it as two galaxies, one inside the other.”
The Sombrero galaxy, also known as NGC 4594, is located 28 million light-years away in the constellation Virgo. From our viewpoint on Earth, we can see the thin edge of its flat disk and a central bulge of stars, making it resemble a wide-brimmed hat. Astronomers do not know whether the Sombrero’s disk is shaped like a ring or a spiral, but agree it belongs to the disk class.
Image Info: The infrared vision of NASA’s Spitzer Space Telescope has revealed that the Sombrero galaxy — named after its appearance in visible light to a wide-brimmed hat — is in fact two galaxies in one. (Credit: NASA/JPL-Caltech)