MACS J0416.1-2403
Astronomers harnessing the combined power of NASA's Hubble and Spitzer space telescopes have found the faintest object ever seen in the early universe. It existed about 400 million years after the big bang, 13.8 billion years ago.
The team has nicknamed the object Tayna, which means "first-born" in
Aymara, a language spoken in the Andes and Altiplano regions of South
America.
Though Hubble and Spitzer have detected other galaxies that are
record-breakers for distance, this object represents a smaller, fainter
class of newly forming galaxies that until now have largely evaded
detection. These very dim objects may be more representative of the
early universe, and offer new insight on the formation and evolution of
the first galaxies.
"Thanks to this detection, the team has been able to study for the
first time the properties of extremely faint objects formed not long
after the big bang," said lead author Leopoldo Infante, an astronomer
at Pontifical Catholic University of Chile (Pontificia Universidad
Católica de Chile). The remote object is part of a discovery of 22
young galaxies at ancient times located nearly at the observable
horizon of the universe. This research is a substantial increase in the
number of known very distant galaxies.
The results are published in the Dec. 3 issue of The Astrophysical Journal.
The new object is comparable in size to the Large Magellanic Cloud
(LMC), a diminutive satellite galaxy of our Milky Way. It is rapidly
making stars at a rate ten times faster than the LMC. The object might
be the growing core of what will likely evolve into a full-sized galaxy.
The small and faint galaxy was only seen thanks to a natural
"magnifying glass" in space. As part of its Frontier Fields program,
Hubble observed a massive cluster of galaxies, MACS J0416.1-2403,
located roughly 4 billion light-years away and weighing as much as a
million billion suns. This giant cluster acts as a powerful natural
lens by bending and magnifying the light of far-more-distant objects
behind it. Like a zoom lens on a camera, the cluster's gravity boosts
the light of the distant protogalaxy to make it look 20 times brighter
than normal. The phenomenon is called gravitational lensing and was
proposed by Albert Einstein as part of his General Theory of Relativity.
Its distance was estimated by building a color profile from combined
Hubble and Spitzer observations. The expansion of the universe causes
the light from distant galaxies to be stretched or reddened with
increasing distance. Though many of the galaxy's new stars are
intrinsically blue-white, their light has been shifted into infrared
wavelengths that are measurable by Hubble and Spitzer. Absorption by
intervening, cool, intergalactic hydrogen also makes the galaxies look
redder.
This finding suggests that the very early universe will be rich in
galaxy targets for the upcoming James Webb Space Telescope to uncover.
Astronomers expect that Webb will allow us to see the embryonic stages
of galaxy birth shortly after the big bang.
Contact
Space Telescope Science Institute, Baltimore, Maryland
410-338-4514
villard@stsci.edu
Whitney Clavin
Jet Propulsion Laboratory, Pasadena, California
818-354-4673
whitney.clavin@jpl.nasa.gov
Leopoldo Infante
Pontifical Catholic University of Chile, Santiago, Chile
011-56-2-354-4939
linfante@astro.puc.cl
Source: HubbleSite
