Sunday, December 6, 2015

NASA Uses Gravitational Lensing To Find Faintest Galaxy In Observable Universe

Hubble Space Telescope view of a very massive cluster of galaxies, MACS J0416.1-2403
This is a Hubble Space Telescope view of a very massive cluster of galaxies, MACS J0416.1-2403, located roughly 4 billion light-years away and weighing as much as a million billion suns. The inset is an image of an extremely faint and distant galaxy that existed only 400 million years after the big bang. Hubble captured it because the gravitational lens makes the galaxy appear 20 times brighter than normal. Credits: NASA, ESA, and L. Infante (Pontificia Universidad Catolica de Chile)

With the help of gravitational lensing first proposed by Albert Einstein as part of his General Theory of Relativity, astronomers have found the faintest object ever seen in the early universe that existed 13.8 billion years ago.



Using the combined power of NASA’s Hubble and Spitzer space telescopes, astronomers discovered a small and faint galaxy which is comparable in size to the Large Magellanic Cloud (LMC). The research team nicknamed the object 'Tayna,' which means "first-born" in Aymara, a language spoken in the Andes and Altiplano regions of South America. Tayna is rapidly making stars at a rate ten times faster than the LMC and may be the growing core of what will likely evolve into a full-sized galaxy.

Although Hubble and Spitzer have detected other galaxies that are record-breakers for distance, Tayna represents a smaller, fainter class of newly-forming galaxies that until now have largely evaded detection. Scientists say that 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 the Pontifical Catholic University of 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. 

Tayna's 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. 

Gravitational Lensing


Tayna 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, MACS0416.1-2403, 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.