MessageToEagle.com - Surprisingly, some of the oldest galaxies in the Universe have three times more stellar mass,
and so many more stars, than all current models of galaxy evolution predict.
A new finding made by the Atlas3D international team, led by an Oxford University scientist, helped to find a way to remove the
'halo' of dark matter that has clouded previous calculations.
The team's analysis means that all current models, which assumed for decades that the light we observe from a galaxy can
be used to infer its stellar mass, will have to be revised.
It also suggests that researchers have a new riddle to ponder: exactly how galaxies forming so early in the life of the
Universe got to be massive so fast.
'The light we see from galaxies is just the tip of the iceberg, but what we really need to measure are galaxy masses
that all models directly predict,' said Dr Michele Cappellari of Oxford University's Department of Physics, who led
'Galaxies can contain huge numbers of small stars, planets or black holes that have lots of mass but give out
very little or no light at all.
'Up until now models assumed that stellar light could be used to infer the stellar masses and any remaining
discrepancy with the observed total mass could be hidden behind a "halo" of dark matter.
Our analysis shows that they can't hide any longer: galaxies are diverse and some have many more stars and are
even stranger than we'd assumed.'
Omega Centauri: the tiny red stars (blue is hot red is cold) are just the sort of faint stars that
can be imaged in a nearby cluster like this one but cannot be seen in distant galaxies. Image: NASA/ESA/Anderson/van der Marel.
Up to now the key limitation on what it was possible to say about the stellar mass of galaxies was the difficulty
in separating this out from the mass contributed by dark matter. Various attempts from independent groups failed
to provide a conclusive answer.
The new analysis succeeded thanks to the availability of two-dimensional maps of stellar motions for a large sample
of galaxies, combined with sophisticated models.
Omega Centauri is the largest and brightest star cluster visible from Earth. It’s in the southern sky
and climbs into our northern hemisphere skies on spring evenings. Photo credits: Spitzer Space Telescope
By disentangling stellar mass from dark matter the team was able to show that instead of the relationship between
observable light and stellar mass being universal, it varies between different types of galaxies - with some older
galaxies having three times the mass suggested by the light they give off.
Dr Cappellari said: 'The question of how you should turn light from a galaxy into a prediction of its mass has been
hotly debated but up until now nobody has been able to kill off the idea that there's a simple and universal way to
convert observed light into mass'.
We now think we've done that by eliminating the "fuzziness" in models caused by dark matter.
'It's exciting because it reveals how much more there is to discover about how galaxies, and the early Universe itself, evolved.'
This research is part of the Atlas3D project and is part-funded by the Science and Technology Facilities Council,
the UK sponsors of astronomy and of the William Herschel Telescope (WHT) that was used by the team. Dr Michele Cappellari
is supported by a Research Fellowship of the Royal Society.
A report of the research 'A systematic variation of the stellar initial mass function in early-type galaxies',
is published in Nature.
Mysteries Of The Sun Explained In Video
Are you curious about the Sun? You now have an excellent chance to learn everything you ever wanted, and even more about our Sun and all its mysteries.
Five new videos called "Mysteries of the Sun" have been just released by NASA.
The videos describe the science of the sun and its effects on the solar system and Earth.
Latest Spectacular Solar Flare Will Hit STEREO-B Spacecraft, Spitzer And Curiosity
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A spectacular solar flare erupted from the Sun's northeastern limb yesterday, sending an beautiful arcing jet of super-heated plasma blasting off into space.
The explosion, captured by Nasa's Solar Dynamics Observatory at about 5.45pm yesterday evening, was one of the most beautiful seen in years.
Something New Spotted On The Sun
One day in the fall of 2011, Neil Sheeley, a solar scientist at the Naval Research Laboratory in Washington, D.C., did what he always does –
look through the daily images of the sun from NASA's Solar Dynamics Observatory (SDO).
But on this day he saw something he'd never noticed before: a pattern of cells with bright centers and dark boundaries occurring in the sun's atmosphere, the corona...
Hidden Misshapen Celestial "Wonder"
It is one of the brightest and strangest objects in the Milky Way - the corpse of a star that exploded around 1000 years ago.
Only a handful of such young supernova remnants are known.
The object named G350.1-0.3 is also incredibly small (only eight light years across) and young in astronomical terms.
Mercury Surprises Scientists
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that reveals new information about the planet's core, topography, and the mysterious radar bright material in the permanently shadowed areas near the poles.
Living Earth Simulator - Supercomputer Predicting The Future
In Douglas Adams book the Hitchhikers Guide to the Galaxy we encounter a machine called Deep Thought. It is the most powerful computer ever built. Deep Thought is capable of answering questions
concerning life, the Universe, and simply everything. Now scientists are planning to create a similar machine. It is called the Living Earth Simulator (LES).