The NASA/ESA Hubble Space Telescope captured this stunning image of the Pegasus dwarf elliptical galaxy, a moon of the Andromeda galaxy.
The Pegasus dwarf elliptical galaxy is located about 959,000 light-years away from the Andromeda galaxy. Image credit: NASA / ESA / D. Weisz, University of California, Berkeley / Gladys Kober, NASA and The Catholic University of California.
of Pegasus dwarf spheroidal galaxy It is located about 2.7 million light years away in the constellation Pegasus.
“The Andromeda Galaxy, also known as Messier 31, is the closest large spiral galaxy to the Milky Way and is orbited by at least 13 dwarf moons,” Hubble astronomers said in a statement.
“The Pegasus dwarf spheroidal galaxy is one of these compact galaxies.”
“Dwarf spheroidal galaxies are the faintest and most massive galaxies known,” they explained.
“They tend to have an elliptical shape and a relatively smooth distribution of stars.”
“Dwarf spheroidal galaxies are typically devoid of gas and contain mostly old and intermediate-stage stars, although some have recently undergone a small amount of star formation.”
The Pegasus dwarf spheroidal galaxy, also known as Andromeda VI, was discovered in 1996 in images from the Second Palomar Observatory Sky Survey (POSS II).
“The galaxy is characterised by a low abundance of heavy elements, leaving very little gas needed to form the next generation of stars, although it still has more than many of the dwarf spheroidal galaxies in our Local Group,” the astronomers said.
“Researchers suspect that Andromeda's gravitational field is stripping away star-forming gas, leaving it with insufficient material to form more than a few generations of stars.”
“By comparison, some of the Milky Way's comparable distant dwarf spheroidal companions contain intermediate-age stars, which may be because the Andromeda Galaxy is so massive and extended that its gravitational influence reaches farther.”
“The jury is still out on how dwarf elliptical galaxies form,” they noted.
“Theories include collisions between galaxies that break off smaller pieces, the gravitational influence of larger galaxies on small, disk-like dwarf galaxies, and processes related to the birth of small systems among dark matter aggregates.”
“Andromeda and the Milky Way are the only galaxies close enough for astronomers to observe these faint satellite galaxies, so clues to their formation come from nearby galaxies like this one.”
“Hubble studied this galaxy as part of a survey of the entire Andromeda moon system to investigate important topics such as dark matter, reionization, and the growth of galactic ecosystems through the ages of the universe.”
Source: www.sci.news
