April 5, 2013
Scientists Discover The Earliest Known Starburst Galaxies In The Universe
Brett Smith for redOrbit.com - Your Universe Online
An international team of researchers announced it has found some of the Universe´s earliest starburst galaxies, essentially young energetic clusters of cosmic gas and dust that form stars at an alarming rate.The discoveries, which were detailed in reports published in Nature and the Astrophysical Journal, were made using the newly inaugurated Atacama Large Millimeter/submillimeter Array (ALMA) telescope.
In its first billions years, the Universe enjoyed its more robust period of star creation, with the most intense bursts of star creation occurring in massive, bright galaxies. The massive amounts of densely packed cosmic material in these starburst galaxies led to the birth of stars at a rapid pace — thousands of times faster than the Milky Way, which generates about a star a year.
In the new study, the astronomers used 16 of ALMA's 66 antennas to determine the distance to 18 of the newly found starburst galaxies. They discovered that these are among the most distant starburst galaxies ever detected, making them some of the oldest galaxies — being viewed when the Universe was only one to three billion years old.
"The more distant the galaxy, the further back in time one is looking, so by measuring their distances we can piece together a timeline of how vigorously the Universe was making new stars at different stages of its 13.7 billion-year history," explained Joaquin Vieira, from Caltech, who was a lead author on the Nature paper.
According to the paper, two of these newly discovered galaxies are the most distant starburst galaxies published to date. The astronomers also noted the detection of water molecules in one of these galaxies, making it the most remote detection of water in the Universe.
"ALMA's sensitivity and wide wavelength range mean we could make our measurements in just a few minutes per galaxy -- about one hundred times faster than before," said co-author Axel Weiss of the Max-Planck-Institute for Radioastronomy (MPIFR) in Bonn, Germany. "Previously, a measurement like this would be a laborious process of combining data from both visible-light and radio telescopes."
"These beautiful pictures from ALMA show the background galaxies warped into arcs of light known as Einstein rings, which encircle the foreground galaxies," added co-author Yashar Hezaveh of McGill University in Montreal. "The dark matter surrounding galaxies half-way across the Universe effectively provides us with cosmic telescopes that make the very distant galaxies appear bigger and brighter."
The latest images demonstrated the power of the newly inaugurated ALMA telescopic array, located 16,400ft above the Chile´s Atacama Desert. The facility is the result of a partnership among Europe, North America and East Asia in cooperation with the Republic of Chile.
"This is an amazing example of astronomers from around the world collaborating to make an exciting discovery with this new facility," said Daniel Marrone, one of the lead authors with the University of Arizona. "This is just the beginning for ALMA and for the study of these starburst galaxies. Our next step is to study these objects in greater detail and figure out exactly how and why they are forming stars at such prodigious rates."