But after looking at telltale signs of galactic mergers among 140 active galaxies, as well as more than 1,200 comparable inactive galaxies, over the last 8 billion years, a team of astronomers found no significant link between the galaxy crashes and black hole outbursts.
“The implication is that the universe is not evolving in such a violent way as previously thought, at least for the last 8 billion years,” research team leader Mauricio Cisternas, an astronomer at the Max Planck Institute for Astronomy in Heidelberg, Germany, told SPACE.com. The universe is thought to be about 13.7 billion years old.
This mosaic image is the sharpest wide-angle view ever obtained of the starburst galaxy, Messier 82 (M82). The galaxy is remarkable for its bright blue disk, webs of shredded clouds and fiery-looking plumes of glowing hydrogen blasting out of its central regions.
Throughout the galaxy’s center, young stars are being born 10 times faster than they are inside our entire Milky Way Galaxy, which results in a huge concentration of young stars carved into the gas and dust at the galaxy’s center. The fierce galactic superwind generated from these stars compresses enough gas to make millions of more stars.
In M82, young stars are crammed into tiny but massive star clusters. These, in turn, congregate by the dozens to make the bright patches, or starburst clumps, in the central parts of M82. The clusters in the clumps can only be distinguished in the sharp Hubble images. Most of the pale, white objects sprinkled around the body of M82 that look like fuzzy stars are actually individual star clusters about 20 light-years across and contain up to a million stars.
The rapid rate of star formation in this galaxy eventually will be self-limiting. When star formation becomes too vigorous, it will consume or destroy the material needed to make more stars. The starburst then will subside, probably in a few tens of millions of years.
The observation was made in March 2006, with Hubble’s Advanced Camera for Surveys‘ Wide Field Channel. Astronomers assembled this six-image composite mosaic by combining exposures taken with four colored filters that capture starlight from visible and infrared wavelengths, as well as the light from the glowing hydrogen filaments.
Astronomers using ESO’s Very Large Telescope (VLT) have measured the distance to the most remote galaxy so far, UDFy-38135539, existing when the Universe was only about 600 million years old (a redshift of 8.6). Image: M. Alvarez, R. Kaehler, and T. Abel
(PhysOrg.com) — A European team of astronomers using ESO’s Very Large Telescope (VLT) has measured the distance to the most remote galaxy so far. By carefully analysing the very faint glow of the galaxy they have found that they are seeing it when the Universe was only about 600 million years old (a redshift of 8.6). These are the first confirmed observations of a galaxy whose light is clearing the opaque hydrogen fog that filled the cosmos at this early time. It has taken 13.1 billion years, travelling at 300,000 kilometres (186,000 miles) per second, for this smudge of infant light to arrive
The distance to faraway galaxies is measured by noting how rapidly they are moving away from our own. Because the universe is expanding at an ever-increasing pace, all widely dispersed galaxies retreat from each other at greater speeds the farther apart they are.
Scientists measure all this by noting a galaxy’s redshift, the extent to which the wavelengths of its light have been stretched toward the red end of the spectrum during its long travels across the cosmos.
The newfound galaxy has a redshift of at least 6.6, based on the Hubble imaging, and may be near 7.0 according to a less firm analysis of the Keck observations.
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