Serpo
23rd July 2013, 03:32 AM
Galaxies a Trillion Times Brighter than the Sun Observed Inside Colossal Amoeba-Like Objects
http://www.dailygalaxy.com/.a/6a00d8341bf7f753ef01901e630b42970b-800wi (http://www.dailygalaxy.com/.a/6a00d8341bf7f753ef01901e630b42970b-pi)
Himiko-lyman-alpha-blob
In 2011, galaxies a trillion times brighter than our Sun were observed by the Spitzer Space Telescope inside enormous blobs that were first found by visible-light telescopes, located billions of light-years away in ancient galactic structures or filaments, where thousands of young galaxies are clustered together. These large, fuzzy galactic halos are made up of hot hydrogen gas and are about 10 times as large as the galaxies they encompass. Astronomers can see glowing blobs, but they don't know what provides the energy to light them up. But they have a hunch.
Lyman-alpha blobs (shown above) are so called because they strongly emit radiation due to the Lyman-alpha emission line of hydrogen gas. Normally, Lyman-alpha emission is in the ultraviolet part of the spectrum, but Lyman-apha blobs are so distant, their light is redshifted to (longer) optical wavelengths.
These huge bodies of gas may be precursors to galaxies. One of these objects, named Himiko (see below) for a legendary, mysterious Japanese queen, stretches for 55 thousand light years, a record for that early point in time. Himiko is located at a transition point in the evolution of the universe called the reionization epoch -- it's as far back as we can see to date.
"It is possible that extremely bright galactic mergers (image above) lie at the center of all the mysterious blobs, but we still don't know how they fuel the blobs themselves," said Dr. Harry Teplitz, Spitzer Science Center, California Institute of Technology. "It's like seeing smoke in the distance and now discovering that it's a forest fire, not a house or car fire, but still not knowing whether it was caused by lightning or arson." The findings will ultimately provide a better understanding of how galaxies, including ones like our own Milky Way, form.
Using its heat-seeking infrared eyes, Spitzer was able to see the dusty galaxies tucked inside one well-known blob located 11 billion light-years away. The findings reveal three monstrously bright galaxies, trillions of times brighter than the Sun, in the process of merging together (image below).
Spitzer also observed three other blobs located in the same cosmic neighborhood, all of which were found to be glaringly bright. One of these blobs is also known to be a galactic merger, only between two galaxies instead of three. It remains to be seen whether the final two blobs studied also contain mergers.
"To figure out what's going on, we need to better characterize the galaxies at the center of the blobs," said Dr. James Colbert, Spitzer Science Center.
That's where Spitzer comes in. Spitzer can sense the infrared glow from the dusty galaxies inside the blobs. When Colbert and colleagues used Spitzer to look at four well-known blobs located in a galactic filament 11 billion light-years away, they discovered that one of them appears to be made up of three galaxies falling into each other -- an unusual cosmic event (image above,right).
The finding is intriguing because previous observations from NASA's Hubble Space Telescope found that another one of the four blobs surrounds a merger between two galaxies. The astronomers speculate that all blobs might share this trait; however, more evidence is needed to close the case.
One clue that the scientists might be on the right track has to do with the infrared brightness of the blob galaxies. To visible-light telescopes, these galaxies appear unremarkable. Spitzer measurements revealed that all four of the galaxies studied are among the brightest in the universe, giving off the equivalent light of trillions of Suns. Such luminous galaxies are often triggered when smaller, gas-rich ones crash together, supporting the notion that galactic mergers might make up the cores of blobs.
Even if galactic mergers are fingered as the culprit, the mystery of the giant galactic blobs will persist. Astronomers will have to figure out why mergers are producing such tremendous clouds of material.
"Far from solving the mystery of the blobs, these observations only deepen it. Not only are the gas clouds bizarre, we now know that they contain some of the brightest and most violent galaxies in the universe," said Teplitz.
One extended Lyman-Alpha blobs astronomers discovered is a mysterious, giant object that existed at a time when the universe was only about 800 million years old. This blob was named Himiko for a legendary, mysterious Japanese queen. It stretches for 55 thousand light years, a record for that early point in time. That length is comparable to the radius of the Milky Way's disk.
http://www.dailygalaxy.com/my_weblog/2013/07/galaxies-a-trillion-times-brighter-than-the-sun-observed-inside-colossal-amoeba-like-blobs-.html
http://www.dailygalaxy.com/.a/6a00d8341bf7f753ef01901e630b42970b-800wi (http://www.dailygalaxy.com/.a/6a00d8341bf7f753ef01901e630b42970b-pi)
Himiko-lyman-alpha-blob
In 2011, galaxies a trillion times brighter than our Sun were observed by the Spitzer Space Telescope inside enormous blobs that were first found by visible-light telescopes, located billions of light-years away in ancient galactic structures or filaments, where thousands of young galaxies are clustered together. These large, fuzzy galactic halos are made up of hot hydrogen gas and are about 10 times as large as the galaxies they encompass. Astronomers can see glowing blobs, but they don't know what provides the energy to light them up. But they have a hunch.
Lyman-alpha blobs (shown above) are so called because they strongly emit radiation due to the Lyman-alpha emission line of hydrogen gas. Normally, Lyman-alpha emission is in the ultraviolet part of the spectrum, but Lyman-apha blobs are so distant, their light is redshifted to (longer) optical wavelengths.
These huge bodies of gas may be precursors to galaxies. One of these objects, named Himiko (see below) for a legendary, mysterious Japanese queen, stretches for 55 thousand light years, a record for that early point in time. Himiko is located at a transition point in the evolution of the universe called the reionization epoch -- it's as far back as we can see to date.
"It is possible that extremely bright galactic mergers (image above) lie at the center of all the mysterious blobs, but we still don't know how they fuel the blobs themselves," said Dr. Harry Teplitz, Spitzer Science Center, California Institute of Technology. "It's like seeing smoke in the distance and now discovering that it's a forest fire, not a house or car fire, but still not knowing whether it was caused by lightning or arson." The findings will ultimately provide a better understanding of how galaxies, including ones like our own Milky Way, form.
Using its heat-seeking infrared eyes, Spitzer was able to see the dusty galaxies tucked inside one well-known blob located 11 billion light-years away. The findings reveal three monstrously bright galaxies, trillions of times brighter than the Sun, in the process of merging together (image below).
Spitzer also observed three other blobs located in the same cosmic neighborhood, all of which were found to be glaringly bright. One of these blobs is also known to be a galactic merger, only between two galaxies instead of three. It remains to be seen whether the final two blobs studied also contain mergers.
"To figure out what's going on, we need to better characterize the galaxies at the center of the blobs," said Dr. James Colbert, Spitzer Science Center.
That's where Spitzer comes in. Spitzer can sense the infrared glow from the dusty galaxies inside the blobs. When Colbert and colleagues used Spitzer to look at four well-known blobs located in a galactic filament 11 billion light-years away, they discovered that one of them appears to be made up of three galaxies falling into each other -- an unusual cosmic event (image above,right).
The finding is intriguing because previous observations from NASA's Hubble Space Telescope found that another one of the four blobs surrounds a merger between two galaxies. The astronomers speculate that all blobs might share this trait; however, more evidence is needed to close the case.
One clue that the scientists might be on the right track has to do with the infrared brightness of the blob galaxies. To visible-light telescopes, these galaxies appear unremarkable. Spitzer measurements revealed that all four of the galaxies studied are among the brightest in the universe, giving off the equivalent light of trillions of Suns. Such luminous galaxies are often triggered when smaller, gas-rich ones crash together, supporting the notion that galactic mergers might make up the cores of blobs.
Even if galactic mergers are fingered as the culprit, the mystery of the giant galactic blobs will persist. Astronomers will have to figure out why mergers are producing such tremendous clouds of material.
"Far from solving the mystery of the blobs, these observations only deepen it. Not only are the gas clouds bizarre, we now know that they contain some of the brightest and most violent galaxies in the universe," said Teplitz.
One extended Lyman-Alpha blobs astronomers discovered is a mysterious, giant object that existed at a time when the universe was only about 800 million years old. This blob was named Himiko for a legendary, mysterious Japanese queen. It stretches for 55 thousand light years, a record for that early point in time. That length is comparable to the radius of the Milky Way's disk.
http://www.dailygalaxy.com/my_weblog/2013/07/galaxies-a-trillion-times-brighter-than-the-sun-observed-inside-colossal-amoeba-like-blobs-.html