Astronomers using NASA’s Spitzer Space Telescope have discovered what they believe is the faint, lumpy glow given off by the very first objects in the Universe.
These two panels show the same slice of sky in the constellation Boötes: 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, and the remaining background glow has been smoothed and enhanced (NASA / JPL-Caltech / GSFC)
These faint objects might be wildly massive stars or voracious black holes. They are too far away to be seen individually, but Spitzer has captured new, convincing evidence of what appears to be the collective pattern of their infrared light.
The observations help confirm the first objects were numerous in quantity and furiously burned cosmic fuel.
“These objects would have been tremendously bright,” said Alexander Kashlinsky of NASA’s Goddard Space Flight Center in Greenbelt, a lead author of a paper to be 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 this remote pattern of light, known as the cosmic infrared background, in 2005, and again with more precision in 2007. Now, Spitzer is in the 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 carefully 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 observed are consistent with the way the very distant objects are thought to be clustered together.
Kashlinsky likens the observations to looking for Fourth of July fireworks in New York City from Los Angeles. First, you would have to remove all the foreground lights between the two cities, as well as the blazing lights of New York City 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.”
_______
Bibliographic information: Kashlinsky A. et al. 2012. New measurements of the cosmic infrared background fluctuations in deep Spitzer/IRAC survey data and their cosmological implications. To be published in ApJ; arXiv:1201.5617v2
