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Scientists discover a Fossil Relic of early Milky Way harboring stars of hugely different ages

These similarities could make Terzan 5 a fossilised relic of galaxy formation, representing one of the earliest building blocks of the Milky Way

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Milky Way Galaxy. Image Source: Wikimedia Commons.

LONDON, Sept 08, 2016: An international team of researchers has found that a stellar system classified as a globular cluster for the 40-odd years since its detection actually has properties uncommon for a globular cluster that make it the ideal candidate for a living fossil from the early days of the Milky Way.

The cluster, known as Terzan 5 — 19,000 light-years from Earth- harbours stars of hugely different ages — an age-gap of roughly seven billion years and bridges the gap in understanding between our galaxy’s past and its present, the study said.

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“Such galactic fossils allow astronomers to reconstruct an important piece of the history of our Milky Way,” explained lead author of the study Francesco Ferraro from University of Bologna in Italy.

While the properties of Terzan 5 are uncommon for a globular cluster, they are very similar to the stellar population which can be found in the galactic bulge, the tightly packed central region of the Milky Way.

These similarities could make Terzan 5 a fossilised relic of galaxy formation, representing one of the earliest building blocks of the Milky Way.

“Terzan 5 could represent an intriguing link between the local and the distant Universe, a surviving witness of the Galactic bulge assembly process,” Ferraro said.

The team scoured data from the Advanced Camera for Surveys and the Wide Field Camera 3 on board Hubble, as well as from a suite of other ground-based telescopes.

They found compelling evidence that there are two distinct kinds of stars in Terzan 5 which not only differ in the elements they contain, but have an age-gap of roughly seven billion years.

The ages of the two populations indicate that the star formation process in Terzan 5 was not continuous, but was dominated by two distinct bursts of star formation.

“This requires the Terzan 5 ancestor to have large amounts of gas for a second generation of stars and to be quite massive. At least 100 million times the mass of the Sun,” co-author of the study Davide Massari from National Institute for Astrophysics (INAF) , Italy.

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Its unusual properties make Terzan 5 the ideal candidate for a living fossil from the early days of the Milky Way, said the study published in the Astrophysical Journal.

Somehow Terzan 5 has managed to survive being disrupted for billions of years, and has been preserved as a remnant of the distant past of the Milky Way.

The researchers believe that this discovery paves the way for a better and more complete understanding of galaxy assembly. (IANS)

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Astronomers Detect Mysterious Radio Wave Far Away From Milky Way

CHIME is composed of four, 100-meter long half-pipe cylinders of metal mesh, which reconstruct images of the sky by processing the radio signals recorded by more than a thousand antennas.

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Space, astronomers
Part of a 64-dish radio telescope system is seen during an official unveiling ceremony, July 13, 2018, in Carnarvon, South Africa. A Canadian radio telescope has detected repeating radio waves from deep space. VOA

Astronomers in Canada have detected a mysterious volley of radio waves from far outside our galaxy, according to two studies published Wednesday in Nature.

What corner of the universe these powerful waves come from and the forces that produced them remain unknown.

The so-called repeating fast radio bursts were identified during the trial run last summer of a built-for-purpose telescope running at only a fraction of its capacity.

Known by its acronym CHIME, the world’s most powerful radio telescope, spread across an area as big as a football pitch, is poised to detect many more of the enigmatic pulses now that it is fully operational.

“At the end of the year, we may have found 1,000 bursts,” said Deborah Good, a PhD student at the University of British Columbia and one of 50 scientists from five institutions involved in the research.

 

Saraswati, astronomers
Earth is part of the Milky way galaxy. Wikimed

 

High energy bursts

Fast radio bursts (FRBs) flash only for a micro-instant, but can emit as much energy as the sun does in 10,000 years.

Exactly what causes these high-energy surges of long waves at the far end of the electromagnetic spectrum remains the subject of intense debate.

More than 60 bursts have been cataloged since 2007, but only one other, observed in 2012 at the Arecibo Observatory in Puerto Rico, was a repeater.

“FRBs, it seems, are likely generated in dense, turbulent regions of host galaxies,” Shriharsh Tendulkar, a corresponding author for both studies and an astronomer at McGill University, told AFP.

Cosmic convulsions created by the turbulent gas clouds that give rise to stars, or stellar explosions such a supernovae, are both possible incubators.

But consecutive radio bursts are a special case.

Space, Astronomers
The world’s largest single-dish radio telescope at the Arecibo Observatory in Arecibo, Puerto Rico, photographed July 13, 2016. Dwindling funds from the U.S. government and construction of bigger, more powerful telescopes are threatening this telescope’s future. VOA

No little green men

“The fact that the bursts are repeated rules out any cataclysmic models in which the source is destroyed while generating the burst,” Tendulkar added.

“An FRB emitted from a merger of two neutron stars, or a neutron star and a black hole, for example, cannot repeat.”

It is not yet clear whether the breeding grounds of repeating bursts are different from those that produce only a single radio pulse.

Significantly, the 2012 and 2018 “repeaters” have strikingly similar properties.

CHIME (Canadian Hydrogen Intensity Mapping Experiment) also spotted a dozen single burst radio waves, but with an unusual profile.

Most FRBs spotted so far have wavelengths of a few centimeters, but these had intervals of nearly a meter, opening up a whole new line of inquiry for astronomers.

Could these enigmatic radio pulses point to intelligence elsewhere in the Universe? Might they be messages in a bottle?

SpaceX, Astronomers
The night sky is lit up above Vandenberg Air Force Base, California, during the launch of a SpaceX rocket carrying an Argentine Earth-observation satellite. VOA

“It is extremely, extremely unlikely,” Tendulkar said.

“As a scientist I can’t rule it out 100 percent. But intelligent life is not on the minds of any astronomer as a source of these FRBs.”

Constructed in British Columbia, CHIME is composed of four, 100-meter long half-pipe cylinders of metal mesh, which reconstruct images of the sky by processing the radio signals recorded by more than a thousand antennas.

Also Read: Astronauts Would Be Able to Grow Beans in Space in 2021: NASA

“This signal processing system is the largest of any telescope on Earth,” the researchers said in a communique.

The other institutions with leading roles are the University of Toronto, the National Research Council of Canada, and the Perimeter Institute. (VOA)