Map of Nearby Galaxy Reveals Incredible Star Formation Process

The Milky Way and even its sister galaxy Andromeda have long passed their phase of peak star formation activity, nonetheless it doesn't necessarily mean that the other galaxies in the Local Group did it as well. Take for example the Triangulum Galaxy, better known to astronomers as M33, a spiral galaxy two times smaller in diameter than the Milky Way and ten times less massive. A new ultraviolet image taken with the help of the Swift telescope reveals a high star formation rate in our neighboring galaxy.

The bright emissions of ultraviolet light is the testimony about these processes, even though the Triangulum galaxy is much smaller in size than our galaxy. Located about 2.9 million light years away from Earth, the Triangulum seems to be in a young evolutionary stage, in a period when it is creating new stars at a frantic rate. Such observations could ultimately end in understanding of how galaxies evolve over time, by creating a so-called "age map" of the galaxy's components.

Stefan Immler from NASA's Goddard Space Flight Center writes that our galaxy and Andromeda would have crossed through a similar period in their lives, before exhausting the gas necessary to form large numbers of stars. The Triangulum will eventually reach a stage in its life when it will find itself in a position identical to that of the Milky Way, unable to create stars at high rates.

According to Immler, the usual procedure in studying star formation processes involves making observations on globular star clusters which form massive amounts of heavy elements, expelled by the stars at the end of their lives, meaning that future stars will have ever higher metallicity content. Originally the first stars, the so-called Population III, had zero metallicity, while our Sun, which is part of the Population I stars, has a relative high content of heavy elements. Just the study of the chemical composition of a galaxy or globular star cluster can give valuable insight in the age map of a particular galaxy, so that scientists can predict how it will evolve in the far future.

High star formation galaxies are usually greatly affected by such processes, due to high speed stellar winds that push heavier elements throughout the volume of the galaxy.

The study conducted by Immler was based on ultraviolet images taken with the Swift Telescope during the previous two months. Similar ultraviolet images can also be produced by the Hubble Space Observatory, however Hubble has a smaller field of view than Swift, meaning that, to create a UV image of the Triangulum galaxy, it would have required to snap more than 100 different photographs. The Swift Observatory was successful in creating this image with only 13. Furthermore, NASA makes use of the GALEX Observatory which can create a wide field image of M33 from only one or two exposures, but it lacks the high resolution provided by Swift.