Scientist: Big galaxies gobble up smaller ones

[Mariboulg]

Scientist: Big galaxies gobble up smaller ones

July 5, 2001 Posted: 7:27 AM EDT (1127 GMT)

Andromeda and its companions

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LONDON, England (Reuters) -- Big galaxies gobble up their smaller neighbors, a scientist said on Wednesday.

Rodrigo Ibata at the Strasbourg Observatory in France said he had discovered a "smear" of stars on the outer reaches of the Andromeda galaxy which are believed to be the remains of Andromeda's satellite dwarf galaxies.

"It shows that small galaxies are being eaten up by big galaxies," Ibata told Reuters. His findings were published in the science journal Nature on Wednesday.

"Large galaxies have been formed by the merging of many smaller galaxies in a hierarchical system. The smaller systems are the first able to be formed, then they start interacting forming larger structures."

Ibata said that like our own Milky Way, the spiral structure of neighboring galaxy Andromeda is surrounded by a sphere or halo of stars and unseen "dark matter."

The group of stars which he discovered is in Andromeda's halo and is situated some three million light years away from Earth.

He said the satellite galaxy appears to have been torn apart and then absorbed by Andromeda's gravitational tidal wave.

Eventually larger galaxies like the Milky Way and Andromeda will interact, but there was no immediate cause for alarm for earthlings, according to Ibata.

The projected collision between the two, which will result in the formation of a single, elliptical galaxy, is not expected for three to four billion years.

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