VLT, Hubble Smash Record for Eyeing Most Distant Galaxy

Planck Time
The Universe. So far, no duplicates found@

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Using the Hubble Space Telescope and the Very Large Telescope (VLT), astronomers have looked back to find the most distant galaxy so far. “We are observing a galaxy that existed essentially when the Universe was only about 600 million years old, and we are looking at this galaxy – and the Universe – 13.1 billion years ago,” said Dr. Matt Lehnert from the Observatoire de Paris, who is the lead author of a new paper in Nature. “Conditions were quite different back then. The basic picture in which this discovery is embedded is that this is the epoch in which the Universe went from largely neutral to basically ionized.”

Lehnert and an international team used the VLT to make follow-up observations of the galaxy — called UDFy-38135539 – which Hubble observations in 2009 had revealed. The astronomers analyzed the very faint glow of the galaxy to measure its distance — and age. This is the first confirmed observations of a galaxy whose light is emerging from the reionization of the Universe.

The reionization period is about the farthest back in time that astronomers can observe. The Big Bang, 13.7 billion years ago, created a hot, murky universe. Some 400,000 years later, temperatures cooled, electrons and protons joined to form neutral hydrogen, and the murk cleared. Some time before 1 billion years after the Big Bang, neutral hydrogen began to form stars in the first galaxies, which radiated energy and changed the hydrogen back to being ionized. Although not the thick plasma soup of the earlier period just after the Big Bang, this galaxy formation started the reionization epoch, clearing the opaque hydrogen fog that filled the cosmos at this early time.

A simulation of galaxies during the era of deionization in the early Universe. Credit: M. Alvarez, R. Kaehler, and T. Abel

“The whole history of the Universe is from the reionization,” Lehnert said during an online press briefing. “The dark matter that pervades the Universe began to drag the gas along and formed the first galaxies. When the galaxies began to form, it reionized the Universe.”

UDFy-38135539 is about 100 million light-years farther than the previous most distant object, a gamma-ray burst.

Studying these first galaxies is extremely difficult, Lehnert said, as the dim light falls mostly in the infrared part of the spectrum because its wavelength has been stretched by the expansion of the Universe — an effect known as redshift. During the time of less than a billion years after the Big Bang, the hydrogen fog that pervaded the Universe absorbed the fierce ultraviolet light from young galaxies.

The new Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope discovered several candidate objects in 2009, and with 16 hours of observations using the VLT, the team was able to was used to detect the very faint glow from hydrogen at a redshift of 8.6.

The team used the SINFONI infrared spectroscopic instrument on the VLT and a very long exposure time.

“Measuring the redshift of the most distant galaxy so far is very exciting in itself,” said co-author Nicole Nesvadba (Institut d’Astrophysique Spatiale), “but the astrophysical implications of this detection are even more important. This is the first time we know for sure that we are looking at one of the galaxies that cleared out the fog which had filled the very early Universe.”

One of the surprising things about this discovery is that the glow from UDFy-38135539 seems not to be strong enough on its own to clear out the hydrogen fog. “There must be other galaxies, probably fainter and less massive nearby companions of UDFy-38135539,” said co-author Mark Swinbank from Durham University, “which also helped make the space around the galaxy transparent. Without this additional help the light from the galaxy, no matter how brilliant, would have been trapped in the surrounding hydrogen fog and we would not have been able to detect it.”

Sources: ESO, press briefing

Hubble Spins the Wheel on Star Birth

Galaxies
Spiral galaxy NGC 3982. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

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Galaxies are like snowflakes, with no two looking exactly the same. The latest image released from the Hubble Space Telescope shows a striking face-on spiral galaxy named NGC 3982, which is a swirl of activity and star birth along with its winding arms. The arms are lined with pink star-forming regions of glowing hydrogen, newborn blue star clusters, and obscuring dust lanes that provide the raw material for future generations of stars. The bright nucleus is home to an older population of stars, which grow ever more densely packed toward the center.

NGC 3982 is located about 68 million light-years away in the constellation Ursa Major. The galaxy spans about 30,000 light-years, one-third of the size of our Milky Way galaxy. This color image is composed of exposures taken by three different instruments, taken over a substantial portion of the space telescope’s life, from March 2000 and August 2009: The Wide Field Planetary Camera 2 (WFPC2), the Advanced Camera for Surveys (ACS), and the Wide Field Camera 3 (WFC3). The observations were taken between The rich color range comes from the fact that the galaxy was photographed in visible and near-infrared light. Also used was a filter that isolates hydrogen emission that emanates from bright star-forming regions dotting the spiral arms.

Source: HubbleSite

Hubble Sees Asteroid Collision in Slow-Motion

The collision between two asteroids in early 2009 produced a strange, X-shaped aftermath. Image Credit: NASA, ESA and D. Jewitt (UCLA)

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Alas, the image above is not marking alien pirate treasure in space – for the first time, the aftermath of a collision between two asteroids has been imaged. Last January, an international team of astronomers saw the strange X-shaped object with the Hubble Space Telescope after ground-based observatories spotted evidence of an asteroid collision in the asteroid belt. The team has now used Hubble to do follow-up observations and uncovered a few surprises about the collision.

The collision produced an X shape, followed by a long comet-like tail. The astronomers, led by David Jewitt of the University of California in Los Angeles, were surprised to find that the collision did not happen as recently as they’d thought, but had actually occurred almost a year previous to the detection. It’s likely that the two asteroids smashed together sometime in February or March of 2009.

“When I saw the Hubbble image I knew it was something special,” said ESA astronomer Jessica Agarwal in a press release.

Named P/2010 A2, the object is located in the asteroid belt between Mars and Jupiter. Asteroid collisions are thought to be a commonplace occurrence, and are responsible for kicking up dust in our Solar System and other planetary systems. Just how much dust is produced, and how frequent the collisions happen is still a hazy topic, and the recent observation of P/2010 A2 should help astronomers to better model this phenomenon.

By figuring out how much dust is produced by the process of ‘collisional grinding’, astronomers could better model the dusty debris disks of other planetary systems, as well as our own.

The team monitored the slow-motion expansion of the leftovers of the colliding asteroids with the Hubble Space Telescope between January and May of 2010. They’ve determined that P/2010 A2 is about 120 meters (393 feet) wide, and the particles of dust that make up the tail following it are between 1 millimeter (0.04 inches) to 2.5 centimeters (1 inch) in diameter.

The collision producing the object P/2010 A2, as observed over the course of a few months by Hubble. Image Credit: NASA, ESA and D. Jewitt (UCLA)

The remnants of the collision suggest that a smaller asteroid – 3 to 5 meters (10-16 feet) wide – collided into a larger one at about 18,000 km per hour (11,000 miles per hour). This vaporized the smaller asteroid, and ejected material from the larger one.

Why is the object X-shaped? That mystery has yet to be determined. It is likely, according to the team, that the filaments produced by the collision suggest asymmetries in the colliding objects. Further observations of P/2010 A2 with the Hubble in 2011 will show just how the collision continues to change, allowing for a more precise model of how it started out.

The observed tail is caused by the same mechanism that produces cometary tails – radiation pressure from the Sun pushes the dust away from the nucleus of the object.

As to why we don’t have thousands of Hubble images to produce a whole alphabet of asteroid collisions shapes – “Catching colliding asteroids on camera is difficult because large impacts are rare, while small ones, such as the one that produced P/2010 A2, are exceedingly faint,” Jewitt said. The results of their observations will be published in the October 14th issue of the journal Nature.

Source: ESA Press Release

Hubble: Helium Reionization Was a Hot Time in the Ol’ Universe

A diagram of the evolution of the universe from the big bang to the present, with two epochs of reionization. Credit: NASA, ESA, and A. Feild (STScI)

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Using Hubble’s newest tool, the Cosmic Origins Spectrograph (COS), researchers have nailed down and enhanced our understanding of the reionization of helium in the early Universe, clarifying the time frame of 11.7 to 11.3 billion years ago when the universe stripped electrons off from primeval helium atoms. Hubble scientists say it was the equivalent of global warming, except that a heat wave blasted through the entire early universe at that time, inhibiting the growth of small galaxies for almost 500 million years.

The universe went through an initial heat wave over 13 billion years ago when energy from early massive stars ionized cold interstellar hydrogen from the Big Bang. This epoch is actually called reionization because the hydrogen nuclei were originally in an ionized state shortly after the Universe’s beginnings.

It took another 2 billion years before the universe produced sources of ultraviolet radiation with enough energy to reionize the helium produced in the Big Bang, which heated intergalactic gas and inhibited it from gravitationally collapsing to form new generations of stars in some small galaxies. The lowest-mass galaxies were not even able to hold onto their gas, and it escaped back into intergalactic space.

This radiation didn’t come from stars, but rather from quasars, the brilliant cores of active galaxies. In fact the epoch when the helium was being reionized corresponds to a transitory time in the universe’s history when quasars were most abundant.

his ultraviolet-light data from the Hubble Space Telescope's Cosmic Origins Spectrograph shows strong helium II absorption and transmission lines from a quasar, identifying an era 11.7 to 11.3 billion years ago when electrons were stripped from primeval helium atoms — a process called reionization. Credit: Shull et al.,

Michael Shull of the University of Colorado and his team were able to find the telltale helium spectral absorption lines in the ultraviolet light from a quasar. The quasar beacon shines light through intervening clouds of otherwise invisible gas, like a headlight shining through a fog. The beam allows for a core-sample probe of the clouds of gas interspersed between galaxies in the early universe.

It was a raucous time. Galaxies frequently collided, and this engorged supermassive black holes in the cores of galaxies with infalling gas. The black holes furiously converted some of the gravitational energy of this mass to powerful far-ultraviolet radiation that would blaze out of galaxies. This heated the intergalactic helium from 18,000 degrees Fahrenheit to nearly 40,000 degrees. After the helium was reionized in the universe, intergalactic gas again cooled down and dwarf galaxies could resume normal assembly.

“I imagine quite a few more dwarf galaxies may have formed if helium reionization had not taken place,” said Shull.

So far Shull and his team only have one sightline to measure the helium transition, but the COS science team plans to use Hubble to look in other directions to see if the helium reionization uniformly took place across the universe.

The science team’s results will be published in the October 20 issue of The Astrophysical Journal.

Source: HubbleSite

Hubble’s Amazing 3-D Look Inside the Dusty Carina Nebula

Dust Pillars in the Carina Nebula. Astronomers are peering inside Carina's pillars to get new details about starbirth activities. Credit: NASA, ESA, and the Hubble Heritage Project (STScI/AURA) Acknowledgment: M. Livio (STScI) and N. Smith (University of California, Berkeley)
Dust Pillars in the Carina Nebula. Astronomers are peering inside Carina's pillars to get new details about starbirth activities. Credit: NASA, ESA, and the Hubble Heritage Project (STScI/AURA) Acknowledgment: M. Livio (STScI) and N. Smith (University of California, Berkeley)

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What can we say? Another Hubble stunner, and just wait until you see flythough video below. This is an absolutely gorgeous look inside the Carina Nebula. The radiation from massive stars inside the nebula eats away at cold molecular clouds, creating bizarre, fantasy-like structures. These are one-light-year-tall pillars of cold hydrogen and dust, imaged by the Hubble Space Telescope’s Advanced Camera for Surveys, in a composite image from observations taken in 2005 in hydrogen light (light emitted by hydrogen atoms) along with observations taken in oxygen light (light emitted by oxygen atoms) in 2010. What Hubble can see from about 7,500 light-years away is nothing short of breathtaking.


Here’s the regular video – in which there are 3-D-type flythough effects:

And grab your 3-D glasses for the full effect:

See more at the HubbleSite. Here’s an article about 3-D Solar System

Hubble Spies an Amazing Cosmic Spiral

An Extraordinary Celestial Spiral. Credit: ESA/NASA & R. Sahai

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The Hubble Space Telescope’s Advanced Camera for Surveys has captured a remarkable image of a spiral in space. No, not a spiral galaxy, (and not another Norway Spiral!) but the formation of an unusual pre-planetary nebula in one of the most perfect geometrical spirals ever seen. The nebula, called IRAS 23166+1655, is forming around the star LL Pegasi (also known as AFGL 3068) in the constellation of Pegasus.

The image shows what appears to be a thin spiral pattern of amazing precision winding around the star, which is itself hidden behind thick dust. Mark Morris from UCLA and an international team of astronomers say that material forming the spiral is moving outwards at a speed of about 50,000 km/hour and by combining this speed with the distance between layers, they calculate that the shells are each separated by about 800 years.

The spiral pattern suggests a regular periodic origin for the nebula’s shape, and astronomers believe that shape is forming because LL Pegasi is a binary star system. One star is losing material as it and the companion star are orbiting each other. The spacing between layers in the spiral is expected to directly reflect the orbital period of the binary, which is estimated to be also about 800 years.

A progression of quasi-concentric shells has been observed around a number of preplanetary nebulae, but this almost perfect spiral shape is unique.

Morris and his team say that the structure of the AFGL 3068 envelope raises the possibility that binary companions are responsible for quasi-concentric shells in most or all of the systems in which they have been observed, and the lack of symmetry in the shells seen elsewhere can perhaps be attributed to orbital eccentricity, to different projections of the orbital planes, and to unfavorable illumination geometries.

Additionally – and remarkably — this object may be illuminated by galactic light.

This image appears like something from the famous “Starry Night” painting by Vincent van Gogh, and reveals what can occur with stars that have masses about half that of the Sun up to about eight times that of the Sun. They do not explode as supernovae at the ends of their lives, but instead can create these striking and intricate features as their outer layers of gas are shed and drift into space. This object is just starting this process and the central star has yet to emerge from the cocoon of enveloping dust.

Abstract: A Binary-Induced Pinwheel Outflow from the Extreme Carbon Star, AFGL 3068

Source: ESA

Supernova Spews Its Guts Across Space

Supernova 1987A and a glowing gas ring encircling the supernova remnant known as the "String of Pearls." Credit: NASA

The recently refurbished Hubble Space Telescope has taken a new look at Supernova 1987A and its famous “String of Pearls,” a glowing ring 6 trillion miles in diameter encircling the supernova remnant. The sharper and clearer images are allowing astronomers to see the “innards” of the star being ejected into space following the explosion, and comparing the new images with ones taken previously provides a unique glimpse of a young supernova remnant as it evolves. They found significant brightening of the object over time, and also evident is how the shock wave from the star’s explosion has expanded and rebounded.

Kevin France from the University of Colorado Boulder and colleagues compared the new Hubble data on the SN1987A taken in 2010 with older images, and observed the supernova in optical, ultraviolet and near-infrared light. They were able to look at the interplay between the stellar explosion and the ‘String of Pearls’ that encircles the supernova remnant. The gas ring — energized by X-rays — likely was spewed out about 20,000 years before the supernova exploded, and shock waves rushing out from the remnant have been brightening some 30 to 40 pearl-like “hot spots” in the ring — objects that likely will grow and merge together in the coming years to form a continuous, glowing circle.

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“The new observations allow us to accurately measure the velocity and composition of the ejected ‘star guts,’ which tell us about the deposition of energy and heavy elements into the host galaxy,” said France, lead author of the study which was published in Science. “The new observations not only tell us what elements are being recycled into the Large Magellanic Cloud, but how it changes its environment on human time scales.”

The significant brightening that was detected is consistent with some theoretical predictions about how supernovae interact with the galactic environment surrounding them. Discovered in 1987, Supernova 1987A is the closest exploding star to Earth to be detected since 1604 and is located in the nearby Large Magellanic Cloud, a dwarf galaxy adjacent to our own Milky Way Galaxy.

In addition to ejecting massive amounts of hydrogen, 1987A has spewed helium, oxygen, nitrogen and rarer heavy elements like sulfur, silicon and iron. Supernovae are responsible for a large fraction of biologically important elements, including oxygen, carbon and iron found in plants and animals on Earth today, France said. The iron in a person’s blood, for example, is believed to have been made by supernovae explosions.

The team compared STIS observations in January 2010 with Hubble observations made over the past 15 years on 1987A’s evolution. STIS has provided the team with detailed images of the exploding star, as well as spectrographic data — essentially wavelengths of light broken down into colors like a prism that produce unique fingerprints of gaseous matter. The results revealed temperatures, chemical composition, density and motion of 1987A and its surrounding environment, said France.

Since the supernova is roughly 163,000 light-years away, the explosion occurred in roughly 161,000 B.C., said France. One light year is about 6 trillion miles.

“To see a supernova go off in our backyard and to watch its evolution and interactions with the environment in human time scales is unprecedented,” he said. “The massive stars that produce explosions like Supernova 1987A are like rock stars — they live fast, flashy lives and die young.”

France said the energy input from supernovae regulates the physical state and the long-term evolution of galaxies like the Milky Way. Many astronomers believe a supernova explosion near our forming sun some 4 to 5 billion years ago is responsible for a significant fraction of radioactive elements in our solar system today, he said.

“In the big picture, we are seeing the effect a supernova can have in the surrounding galaxy, including how the energy deposited by these stellar explosions changes the dynamics and chemistry of the environment,” said France. “We can use this new data to understand how supernova processes regulate the evolution of galaxies.”

France and his team will be looking at Supernova 1987A again with Hubble’s Cosmic Origins Spectrograph, an instrument which scientists hope will help them better understand the “cosmic web” of of material permeating the cosmos and learn more about the conditions and evolution of the early universe.

Source: ScienceExpress

Giant Ultraviolet Rings Found Around Ancient Galaxies

Astronomers have found unexpected rings and arcs of ultraviolet light around a selection of galaxies, four of which are shown here as viewed by NASA's and the European Space Agency's Hubble Space Telescope. Image credit: NASA/ESA /JPL-Caltech/STScI/UCLA

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Title this ‘Zombie Galaxies’ or ‘Night of the Living Galaxies.’ Astronomers have found mysterious, giant loops of ultraviolet light around old, massive galaxies, which were presumed to be “dead,” and these galaxies seem to have come back to life. Somehow these “over-the-hill galaxies” have been infused with fresh gas to form new stars that power these truly gargantuan rings, some of which could encircle several Milky Way galaxies.

The discovery of these rings implies that old bloated galaxies that were once devoid of star-making can be reignited with star birth, and that galaxy evolution does not proceed straight from the cradle to the grave.

“In a galaxy’s lifetime, it must make the transition from an active, star-forming galaxy to a quiescent galaxy that does not form stars,” said Samir Salim, lead author of a recent study and a research scientist in the department of astronomy at Indiana University, Bloomington. “But it is possible this process goes the other way, too, and that old galaxies can be rejuvenated.”

Using two orbiting observatories, NASA’s Galaxy Evolution Explorer and Hubble Space Telescope, the astronomers surveyed a vast region of the sky in ultraviolet light. GALEX picked out 30 elliptical and lens-shaped “early” galaxies with puzzlingly strong ultraviolet emissions but no signs of visible star formation, and Hubble was used to take a closer look.

What Hubble showed shocked the astronomers. Three-quarters of the galaxies were spanned by great, shining rings of ultraviolet light, with some ripples stretching 250,000 light-years. A few galaxies even had spiral-shaped ultraviolet features.

“We haven’t seen anything quite like these rings before,” said Michael Rich, co-author of the paper and a research astronomer at UCLA. “These beautiful and very unusual objects might be telling us something very important about the evolution of galaxies.”

But astronomers are unsure where the gas for this galactic resurrection came from and how it has created rings. One possibility is that a smaller galaxy merged with a big, old one, bringing in fresh gas to spawn hordes of new stars, and could in rare instances give rise to the ring structures as well.

But the researchers have their doubts about this origin scenario. “To create a density shock wave that forms rings like those we’ve seen, a small galaxy has to hit a larger galaxy pretty much straight in the center,” said Salim. “You have to have a dead-on collision, and that’s very uncommon.”

Another option that the astronomers like better is that the rejuvenating spark could have come from a gradual sopping-up of the gas in the so-called intergalactic medium, the thin soup of material between galaxies. This external gas could generate these rings, especially in the presence of bar-like structures that span some galaxies’ centers.

Ultimately, more observations will be needed to show how these galaxies began growing younger and lit up with humongous halos. Salim and Rich plan to search for more evidence of bars, as well as faint structures that might be the remnants of stellar blooms that occurred in the galaxies’ pasts. Rather like recurring seasons, it may be that galaxies stirred from winter can breed stars again and then bask in another vibrant, ultraviolet-soaked summer.

The study detailing the findings appeared in the April 21 issue of the Astrophysical Journal.

Source: JPL

Hubble Confirms Comet-like Tail on Vaporizing Planet

Next time you hear someone complaining that it’s too hot outside, you can make them feel better by pointing out that at least their planet isn’t so hot it is vaporizing into space. Unless of course you happen to be speaking to someone from the gaseous extrasolar planet HD 209458b.

New observations from the Hubble Cosmic Origins Spectrograph (COS) confirm suspicions from 2003 that the planet HD 209458b is behaving like a Jupiter-sized comet, losing its atmosphere in a huge plume due to the powerful solar wind of its too-close star.

HD 209458b is a “hot Jupiter”: a gas giant that orbits extremely close to its star. It whips around its star in 3.5 days, making even speedy little Mercury with its 88 day orbit around the sun look like a slacker.

Astronomers have managed to learn a lot about HD 209458b because it is a transiting planet. That means that its orbit is aligned just right, so from our point of view it blocks some of the light from its star. When that happens, it gives hints at the planet’s size, and gives a much better constraint on the mass. HD 209458b is a little more than two thirds the mass of Jupiter, but heat from its star has puffed it up to two and a half times Jupiter’s diameter.

In the case of HD 209458b, during transits some of the star’s light passes through the planet’s escaping, 2,000-degree-Fahrenheit atmosphere, allowing scientists to tell what it is made of and how fast it is being lost to space.

“We found gas escaping at high velocities, with a large amount of this gas flowing toward us at 22,000 miles per hour,” said astronomer Jeffrey Linsky of the University of Colorado in Boulder, leader of the COS study. “This large gas flow is likely gas swept up by the stellar wind to form the comet-like tail trailing the planet.”

The escaping planetary gases absorbed starlight at wavelengths characteristic of heavier elements like carbon and silicon, suggesting that the star’s intense heat is driving circulation deep in HD 209458b’s atmosphere, dredging up material that would otherwise remain far beneath lighter elements like hydrogen.

Even though its atmosphere is constantly streaming away into space, HD 209458b won’t be disappearing anytime soon. At the measured rate of loss, the planet would last about a trillion years, far longer than the lifetime of its host star.

So, be thankful that even on hot summer days, your planet is in no danger of being vaporized by its star. And if you do happen to be speaking to someone from HD 209458b, you can reassure them that their planet will still be there when they return home. Well, most of it, anyway.

Oh, and remind them to stock up on sunscreen.

Hubble, Bubble, Toil and Star Formation

A colorful star-forming region in NGC 2467. Credit: NASA, ESA and Orsola De Marco (Macquarie University)

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OK, that headline doesn’t rhyme, but this incredible new Hubble image looks like a witch’s cauldron of an exotic cosmic brew. It billows with huge clouds of gas and dust and is sprinkled with Eye of Newt, um…er, bright blue hot young stars. These dust clouds in NGC 2467 look like a murky, shadowy liquid, but they are actually star forming regions made mostly of hydrogen, perfect for bubbling up newborn stars. And your little dog, too.

NGC 2467 lies in the southern constellation of Puppis, approximately 13,000 light-years from Earth.

The picture was created from images taken with the Wide Field Channel of the Advanced Camera for Surveys through three different filters (F550M, F660N and F658N, shown in blue, green and red respectively). These data were taken in 2004 but just released today.

This region looks somewhat like the Orion Nebula and the hot young stars that recently formed among this bubbling brew are emitting fierce ultraviolet radiation that is causing the whole scene to glow while also sculpting the environment and gradually eroding the gas clouds. Studies have shown that most of the radiation comes from the single hot and brilliant massive star just above the center of the image. Its fierce radiation has cleared the surrounding region and some of the next generation of stars are forming in the denser regions around the edge.

Source: ESA Hubble