Astronomers discover 'missing link' in galaxy evolution.Byline: ANI Washington, Nov 26 (ANI): Astronomers at the University of Nottingham The University of Nottingham is a leading research and teaching university in the city of Nottingham, in the East Midlands of England. It is a member of the Russell Group, and of Universitas 21, an international network of research-led universities. in the UK have identified a type of galaxy that could be the 'missing link' in our understanding of galaxy evolution. The discovery is part of the STAGES study, led by the University's Centre for Astronomy and Particle Theory, which is examining galaxy evolution using images from the Hubble Space Telescope Hubble Space Telescope (HST), the first large optical orbiting observatory. Built from 1978 to 1990 at a cost of $1.5 billion, the HST (named for astronomer E. P. Hubble) was expected to provide the clearest view yet obtained of the universe. . Astronomers place most normal galaxies into two camps according to their visual appearance: either disk-like systems like our own Milky Way, or round, rugby-ball shaped collections of stars known as ellipticals. In most cases, a galaxy's shape matches its colour. Spiral galaxies appear blue because they are still vigorously forming hot young stars. Elliptical galaxies, on the other hand, are mostly old, dead and red, and tend to cluster together in crowded regions of space. STAGES has identified a population of unusual red spiral galaxies that are setting out on the road to retirement after a lifetime of forming stars. The team discovered that, despite their colour, the red spirals are actually hiding star formation behind a shroud of dust. Invisible to Hubble's eye, this star formation is only detectable in the infrared part of the spectrum - radiation emitted from the galaxies at wavelengths longer than visible light. The star formation in blue spiral galaxies is gradually shut off and hidden behind dust, before petering out to form smooth "lenticular lenticular /len·tic·u·lar/ (len-tik´u-ler) 1. pertaining to or shaped like a lens. 2. pertaining to the lens of the eye. 3. pertaining to the lenticular nucleus. " (lens-shaped) red galaxies with no trace of spiral arms. To go further and transform the galaxy into an elliptical el·lip·tic or el·lip·ti·cal adj. 1. Of, relating to, or having the shape of an ellipse. 2. Containing or characterized by ellipsis. 3. a. shape would require more violent mechanisms, such as the collision of galaxies. Dr Christian Wolf, an STFC STFC Swindon Town Football Club STFC Self Test Feature Check STFC Shrewsbury Town Football Club STFC Star Trek: First Contact STFC Saskatoon Track and Field Club (Saskatoon, SK, Canada) Advanced Research Fellow at the University of Oxford, trained the Hubble Space Telescope on a region of space crowded with galaxies known as the A901/902 supercluster su·per·clus·ter n. A group of neighboring clusters of galaxies. supercluster A large group of neighboring clusters of galaxies, along with isolated galaxies scattered between them, the entire collection for the STAGES project. He uncovered a surprisingly large population of spiral galaxies in the supercluster that are red in colour. Within the supercluster, Dr Wolf discovered that the red spirals were hiding low levels of hidden star formation, despite their otherwise lifeless appearance in visible light. The next step for both teams is to find out exactly what shuts off the star formation, by looking inside the galaxies themselves. They suspect that behind the slow demise of galaxies is a process known as strangulation strangulation /stran·gu·la·tion/ (strang?gu-la´shun) 1. choke (2). 2. arrest of circulation in a part due to compression. See hemostasis (2). stran·gu·la·tion n. , in which a galaxy's fuel supply is stripped away as it encounters the crowd. Starved of the raw material needed to form new stars, it will slowly change colour from blue to red as its existing stars age. (ANI) Copyright 2008 Asian News International The Asian News International (ANI) agency provides multimedia news to China and 50 bureaus in India. It covers virtually all of South Asia since its foundation and presently claims, on its official website, to be the leading South Asia-wide news agency. (ANI) - All Rights Reserved. Provided by Syndigate.info an Albawaba.com company |
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