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13 Dec 12 Surprise Radio Jets Revealed in Hercules A Galaxy

A supermassive black hole powers jets of cosmic rays on either side the elliptical radio galaxy Hercules A.
CREDIT: NASA, ESA, S. Baum and C. O’Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA)

An amazing new radio image of elliptical galaxy Hercules A reveals two gigantic cosmic jets shooting from its center.

The galaxy, also called 3C 348, lies some 2 billion light-years away and is the brightest known radio-emitting object in the constellation Hercules.

In optical images from the Hubble Space Telescope‘s Wide Field Camera 3, Hercules A seems to be a quite ordinary galaxy, seen glowing, yellowish in color at the center of this image.

But superimposed radio data from the Very Large Array (VLA) in New Mexico shows jets that would be invisible to the human eye, stretching out one-and-a-half million light-years across, according to NASA. Made up of high-energy plasma beams, subatomic particles and magnetic fields, these jets are powered by the gravitational energy of the galaxy’s supermassive black hole.

“It’s both beautiful and fascinating to look at,” astronomer Stefi Baum, of the Rochester Institute of Technology, said in a statement Monday (Dec. 10).

Baum and her fellow RIT researcher Chris O’Dea found unexpected differences between the Hubble images and the radio images regarding the appearance of the dust clouds and jets on the two sides of galaxy.

“One side has dusty filaments of cold gas that lie along the edges of the radio jet, suggesting they have been dragged along, or entrained, by the outflowing radio plasma; but the other side of the source shows dusty filaments which resemble two bubbles,” Baum said of the Hubble data, explaining that the radio data revealed the reverse.

“The side that has the dust bubbles is the side with the normal looking collimated jet and the side with what looks like more entrained dust is the side that has the very unusual bubbles in the radio,” she said. “We’re perplexed so far.”

O’Dea said the differences between the characteristics of the cold gas and jets “supports the idea that the differences in radio properties are established on larger scales as the jets interact with their environments” while traveling outward from the galaxy.

The researchers have not completed a full analysis of the radio data, which they say might help refine models predicting the radio emissions from the galaxy.

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13 Dec 12 Ancient Galaxy May Be Most Distant Ever Seen

Hubble Ultra Deep Field 2012

This new image of the Hubble Ultra Deep Field (HUDF) 2012 campaign reveals a previously unseen population of seven faraway galaxies, which are observed as they appeared in a period 350 million to 600 million years after the big bang.
CREDIT: NASA, ESA, R. Ellis (Caltech), and the UDF 2012 Team

Astronomers have spotted seven galaxies that existed just a few hundred million years after the universe’s birth, including one that may be the oldest found to date.

The potential record-holding galaxy, known as UDFj-39546284, likely existed when the universe was just 380 million years old, researchers said, and may be the farthest galaxy ever seen. The other six distant galaxies all formed within 600 million years of the Big Bang, which created our universe 13.7 billion years ago.

UDFj-39546284 was detected previously, and researchers had thought it formed just 500 million years or so after the Big Bang. The new observations, made using NASA’s Hubble Space Telescope, push its probable formation time back even further.

The seven galaxies constitute the first reliable census of the epoch from 400 million to 600 million years after the universe’s birth, researchers said. This census detects a steady increase in galaxies over this period, suggesting that the formation of the first stars and galaxies — the so-called “cosmic dawn” — happened gradually rather than suddenly.

“The cosmic dawn was probably not a single, dramatic event,” study lead author Richard Ellis, of Caltech in Pasadena, told reporters today (Dec. 12). [Gallery: Spectacular Hubble Photos]

Ellis and his team pointed Hubble at a small patch of sky known as the Hubble Ultra Deep Field, which the telescope observed for many hours to build up enough light to spot extremely faint, distant objects. The researchers used Hubble’s Wide Field Camera 3 to study the deep field in near-infrared wavelengths during August and September 2012.

The astronomers used special filters to measure the galaxies’ redshifts — how much their light has been stretched by the expansion of space. From the redshifts, the researchers were able to calculate the distance to each galaxy, revealing their ages.

The results “reprensent our cosmic roots,” said Harvard astronomer Abraham Loeb, who was not involved in the study. The new Hubble data “comes from the biggest archeological dig that we have of the universe.”

The team pushed Hubble to its limits, and the telescope probably won’t be able to see back in time any further, Ellis said. But NASA’s James Webb Space Telescope, which is slated to launch in 2018, will dig even deeper into the universe’s past.

“Hubble has, in a sense, set the stage for Webb,” team member Anton Koekemoer, of the Space Telescope Science Institute in Baltimore, said in a statement. “Our work indicates there is a rich field of even earlier galaxies that Webb will be able to study.”

The new study has been accepted for publication in The Astrophysical Journal Letters.

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