Blog 5: Discovering Teenage Galaxies Billiions of Light Years Away

The main idea behind this article is summed up by a quote used in the article. Michael Rauch, one of the key players in the observations said, "But as often happens in science we got a surprise and found something we weren't looking for--."

Using ESO's Very Large Telescope a team of astronomers found faint light from billions of light years away, which are believed to be teenage galaxies which are considered the "building blocks of normal galaxies like our Milky Way." These galaxies have eluded detection previously because a large amount of time was required even with an 8-meter telescope like the VLT, and the amount of time needed greatly exceeded the normal observing time awards. However, the team of astronomers, which included Martin Haehnelt of the University of Cambridge, Michael Rauch and George Becker of the Observatories of the Carnegie Institution, and Andy Bunker of the Anglo-Australian Observatory, used even periods of poor weather, using the service mode to obtain the observing time they needed. These observations were actually done in order to measure a faint signal from intergalactic gas caused by cosmic UV background radiation. Instead however, they found "dozens of faint, discrete objects emitting radiation from neutral hydrogen in the ... Lyman-alpha line" which is a defined characteristic of protogalaxies. The light signal coming from this small piece of sky implies low star formation and a small amount of chemical enrichment which leads the team to believe that these are galaxies in early stages of formation. This discovery is "particularly exciting...[because] it opens the route to find large numbers of bulidng blocks of normal galaxies and that we will now be able to study in detail how galaxies like our Milky Way have come together", according to Haehnelt. The discovery of these galaxies also lends support to the theory of galaxy formation that suggests that gas accreted forms smaller protogalaxies, which then collide and merge to become the massive galaxies seen today.

Although I don't see this as one of the more exciting news releases I've read, the fact that further observations of galaxies like these will infact help us better understand our own galaxy is always encouraging. The fact that these observations were made in the service mode, when the weather was not always perfect I do enjoy though, because it shows that observations don't have to be controlled completely by the weather which is so often what happens. Because the time needed for this was so extensive, the ESO staff astronomers were actually responsible for carrying out the actual observations. This shows that those kinds of observations that need a much longer time than the usual observing time awards can be done, and are just as effective.

Reference: ESO. "Discovering Teenage Galaxies Billions Of Light Years Away." ScienceDaily 28 November 2007. 29 November 2007 .