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First cosmic objects burned brightly, astronomers say

June 7, 2012
Courtesy of NASA Jet Propulsion Laboratory
and World Science staff

A faint, lumpy glow from the first ob­jects in the uni­verse may have been de­tected with the best pre­ci­sion yet, us­ing NASA’s Spitzer Space Tel­e­scope, as­tro­no­mers say.

The ob­jects might be enor­mous stars or vo­ra­cious black holes, the sci­en­tists add; they’re too dis­tant to make out in­di­vid­u­ally, but Spitzer has cap­tured ev­i­dence of what seems to be an over­all pat­tern cre­at­ed by their light. The ob­serva­t­ions help con­firm the first ob­jects were nu­mer­ous and burned fu­ri­ous­ly, as­tro­no­mers claim.

“These ob­jects would have been tre­men­dously bright,” said Al­ex­an­der “Sasha” Kash­lin­sky of NASA’s God­dard Space Flight Cen­ter in Green­belt, Md., lead au­thor of a pa­per on the find­ings pub­lished in The As­t­ro­phys­i­cal Jour­nal. “We can’t yet di­rectly rule out mys­te­ri­ous sources for this light that could be com­ing from our near­by uni­verse, but it is now becom­ing in­creas­ingly likely that we are catch­ing a glimpse of an an­cient ep­och. Spitzer is lay­ing down a roadmap for NASA’s upcom­ing James Webb Tel­e­scope, which will tell us ex­actly what and where these first ob­jects were.”

Courtesy NASA/JPL-Caltech/GSFC

The above panels show the same slice of sky in the constellation Boötes, dubbed the "Extended Groth Strip." The area covered is about 1 by 0.12 degrees of sky. The top panel show's Spitzer's initial infrared view of this patch, including foreground stars and a confusion of fainter galaxies. In the lower panel, all of the resolved stars and galaxies have been masked out of the image (grey patches), and the remaining background glow has been smoothed and enhanced. This processing reveals structure too faint to be seen in the original image. The structure of the lower panel matches just what we would expect for the patterns of clusters from the first galaxies formed in the universe, scientists say. Although any particular early galaxy would be too faint to see individually, this technique is thought to let astronomers better understand what things were like shortly after the Big Bang. 


The Spitzer telescope first caught hints of the re­mote pat­tern of light, known as the cos­mic in­fra­red back­ground, in 2005, and again with more pre­ci­sion in 2007. Now, Spitzer is in an ex­tend­ed phase of its mis­sion, dur­ing which it per­forms more in-depth stud­ies on spe­cif­ic patches of the sky. Kash­lin­sky and his col­leagues used Spitzer to look at two patches of sky for more than 400 hours each.

The team then sub­tracted all the known stars and ga­lax­ies in the im­ages. Rath­er than be­ing left with a black, emp­ty patch of sky, they found faint pat­terns of light with sev­er­al tell­tale char­ac­ter­is­tics of the cos­mic in­fra­red back­ground. The lumps in the pat­tern are con­sist­ent with the way the very dis­tant ob­jects are thought to be clus­tered to­geth­er, the re­search­ers said.

Kash­lin­sky likens the ob­serva­t­ions to look­ing for fire­works in New York ­city from Los An­ge­les. First, you’d have to re­move all the fore­ground lights be­tween the two ­ci­ties, as well as the blaz­ing lights of New York it­self. You ul­ti­mately would be left with a fuzzy map of how the fire­works are dis­trib­ut­ed, but they would still be too dis­tant to make out in­di­vid­u­ally.

“We can gath­er clues from the light of the uni­verse’s first fire­works,” said Kash­lin­sky. “This is teach­ing us that the sources, or the “s­parks,” are in­tensely burn­ing their nu­clear fu­el.”

The uni­verse is thought to have formed some 13.7 bil­lion years ago in a fiery, ex­plo­sive event called the Big Bang. With time, it cooled and, by around 500 mil­lion years lat­er, the first stars, ga­lax­ies and black holes be­gan to take shape. As­tro­no­mers say some of that “first light” might have trav­eled bil­lions of years to reach the Spitzer Space Tel­e­scope. The light now ap­pears as in­fra­red—a low-energy form of light in­vis­i­ble to the un­aided eye­—be­cause the uni­verse has been ex­pand­ing, a pro­cess that stretches out light waves, turn­ing them in­to in­fra­red.

The new study was de­signed to im­prove on pre­vi­ous ob­serva­t­ions by meas­ur­ing this cos­mic in­fra­red back­ground out to scales equiv­a­lent to two full moon­s—a good deal larg­er than what was de­tected be­fore. Im­ag­ine try­ing to find a pat­tern in the noise in an old-fash­ioned tel­e­vi­sion set by look­ing at just a small piece of the screen. It would be hard to know for cer­tain if a sus­pected pat­tern was real. By see­ing a larg­er sec­tion of the screen, you could re­solve small- and large-scale pat­terns, fur­ther con­firming your in­i­tial sus­pi­cion.

Like­wise, as­tro­no­mers us­ing Spitzer have in­creased the amount of sky ex­am­ined to ob­tain more de­fin­i­tive ev­i­dence of the cos­mic in­fra­red back­ground. The re­search­ers plan to ex­plore more patches of sky in the fu­ture to gath­er more clues hid­den in the light of that an­cient time.


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A faint, lumpy glow given off by the very first objects in the universe may have been detected with the best precision yet, using NASA’s Spitzer Space Telescope, astronomers say. The objects might be enormous stars or voracious black holes, the scientists add; they’re too distant to be seen individually, but Spitzer has captured evidence of what seems to be an overall pattern created by their light. The observations help confirm the first objects were numerous and burned furiously, astronomers claim. “These objects would have been tremendously bright,” said Alexander “Sasha” Kashlinsky of NASA’s Goddard Space Flight Center in Greenbelt, Md., lead author of a paper on the findings published in The Astrophysical Journal. “We can’t yet directly rule out mysterious sources for this light that could be coming from our nearby universe, but it is now becoming increasingly likely that we are catching a glimpse of an ancient epoch. Spitzer is laying down a roadmap for NASA’s upcoming James Webb Telescope, which will tell us exactly what and where these first objects were.” Spitzer first caught hints of the remote pattern of light, known as the cosmic infrared background, in 2005, and again with more precision in 2007. Now, Spitzer is in an extended phase of its mission, during which it performs more in-depth studies on specific patches of the sky. Kashlinsky and his colleagues used Spitzer to look at two patches of sky for more than 400 hours each. The team then subtracted all the known stars and galaxies in the images. Rather than being left with a black, empty patch of sky, they found faint patterns of light with several telltale characteristics of the cosmic infrared background. The lumps in the pattern are consistent with the way the very distant objects are thought to be clustered together, the researchers said. Kashlinsky likens the observations to looking for fireworks in New York City from Los Angeles. First, you’d have to remove all the foreground lights between the two cities, as well as the blazing lights of New York itself. You ultimately would be left with a fuzzy map of how the fireworks are distributed, but they would still be too distant to make out individually. “We can gather clues from the light of the universe’s first fireworks,” said Kashlinsky. “This is teaching us that the sources, or the “sparks,” are intensely burning their nuclear fuel.” The universe is thought to have formed some 13.7 billion years ago in a fiery, explosive event called the Big Bang. With time, it cooled and, by around 500 million years later, the first stars, galaxies and black holes began to take shape. Astronomers say some of that “first light” might have traveled billions of years to reach the Spitzer Space Telescope. The light now appears as infrared—a low-energy form of light invisible to the unaided eye—because the universe has been expanding, a process that stretches out light waves, turning them into infrared. The new study was designed to improve on previous observations by measuring this cosmic infrared background out to scales equivalent to two full moons—a good deal larger than what was detected before. Imagine trying to find a pattern in the noise in an old-fashioned television set by looking at just a small piece of the screen. It would be hard to know for certain if a suspected pattern was real. By seeing a larger section of the screen, you could resolve small- and large-scale patterns, further confirming your initial suspicion. Likewise, astronomers using Spitzer have increased the amount of sky examined to obtain more definitive evidence of the cosmic infrared background. The researchers plan to explore more patches of sky in the future to gather more clues hidden in the light of this ancient era.