Anarchic Star Formation Found In Dust Cloud

The Danish 1.54-metre telescope located at ESO’s La Silla Observatory in Chile has captured a striking image of NGC 6559, an object that showcases the anarchy that reigns when stars form inside an interstellar cloud. Credit: ESO

If you think that breaking all the rules is cool, then you’ll appreciate one of the latest observations submitted by the Danish 1.54 meter telescope housed at ESO’s La Silla Observatory in Chile. In this thought-provoking image, you’ll see what kind of mayhem occurs when stars are forged within an interstellar nebula.

Towards the center of the Milky Way in the direction of the constellation of Sagittarius, and approximately 5000 light-years from our solar system, an expansive cloud of gas and dust await. By comparison with other nebulae in the region, this small patch of cosmic fog known as NGC 6559 isn’t as splashy as its nearby companion nebula – the Lagoon (Messier 8). Maybe you’ve seen it with your own eyes and maybe you haven’t. Either way, it is now coming to light for all of us in this incredible image.

Comprised of mainly hydrogen, this ethereal mist is the perfect breeding ground for stellar creation. As areas contained within the cloud gather enough matter, they collapse upon themselves to form new stars. These neophyte stellar objects then energize the surrounding hydrogen gas which remains around them, releasing huge amounts of high energy ultraviolet light. However, it doesn’t stop there. The hydrogen atoms then merge into the mix, creating helium atoms whose energy causes the stars to shine. Brilliant? You bet. The gas then re-emits the energy and something amazing happens… an emission nebula is created.

Loading player…

This zoom starts with a broad view of the Milky Way. We head in towards the centre, where stars and the pink regions marking star formation nurseries are concentrated. We see the huge gas cloud of the Lagoon Nebula (Messier 8) but finally settle on the smaller nebula NGC 6559. The colourful closing image comes from the Danish 1.54-metre telescope located at ESO’s La Silla Observatory in Chile. Credit: ESO/Nick Risinger (skysurvey.org)/S. Guisard. Music: movetwo

In the center of the image, you can see the vibrant red ribbon of the emission nebula, but that’s not the only thing contained within NGC 6559. Here swarms of solid dust particles also exist. Consisting of tiny bits of heavier elements, such as carbon, iron and silicon, these minute “mirrors” scatter the light in multiple directions. This action causes NGC 6559 to be something more than it first appears to be… now it is also a reflection nebula. It appears to be blue thanks to the magic of a principle known as Rayleigh scattering – where the light is projected more efficiently in shorter wavelengths.

Don’t stop there. NGC 6559 has a dark side, too. Contained within the cloud are sectors where dust totally obscures the light being projected behind them. In the image, these appear as bruises and dark veins seen to the bottom left-hand side and right-hand side. In order to observe what they cloak, astronomers require the use of longer wavelengths of light – ones which wouldn’t be absorbed. If you look closely, you’ll also see a myriad of saffron stars, their coloration and magnitude also effected by the maelstrom of dust.

It’s an incredible portrait of the bedlam which exists inside this very unusual interstellar cloud…

Original Story Source: ESO News Release.

Region in LMC Ablaze with Light and Color

Nearly 200 000 light-years from Earth, the Large Magellanic Cloud, a satellite galaxy of the Milky Way, floats in space, in a long and slow dance around our galaxy. As the Milky Way’s gravity gently tugs on its neighbour’s gas clouds, they collapse to form new stars. In turn, these light up the gas clouds in a kaleidoscope of colours, visible in this image from the NASA/ESA Hubble Space Telescope.

Hubble view of star formation region N11 from the NASA/ESA Hubble Space Telescope. Image credit: NASA/ESA Hubble. Zoom by John Williams/TerraZoom using Zoomify.

New computer wallpaper alert. Light from the Large Magellanic Cloud takes nearly 200,000 years to travel to Earth. And it’s worth the wait.

Behold LHA 120-N 11, or just simply N11, in this image from the NASA/ESA Hubble Space Telescope.

Continue reading “Region in LMC Ablaze with Light and Color”

The Brightest Galaxies in the Universe Were Invisible… Until Now

Hubble images of six of the starburst galaxies first found by ESA’s Herschel Space Observatory (Keck data shown below each in blue)

Many of the brightest, most actively star-forming galaxies in the Universe were actually undetectable by Earth-based observatories, hidden from view by thick clouds of opaque dust and gas. Thanks to ESA’s Herschel space observatory, which views the Universe in infrared, an enormous amount of these “starburst” galaxies have recently been uncovered, allowing astronomers to measure their distances with the twin telescopes of Hawaii’s W.M. Keck Observatory. What they found is quite surprising: at least 767 previously unknown galaxies, many of them generating new stars at incredible rates.

Although nearly invisible at optical wavelengths these newly-found galaxies shine brightly in far-infrared, making them visible to Herschel, which can peer through even the densest dust clouds. Once astronomers knew where the galaxies are located, they were able to target them with Hubble and, most importantly, the two 10-meter Keck telescopes — the two largest optical telescopes in the world.

By gathering literally hundreds of hours of spectral data on the galaxies with the Keck telescopes, estimates of their distances could be determined as well as their temperatures and how often new stars are born within them.

“While some of the galaxies are nearby, most are very distant; we even found galaxies that are so far that their light has taken 12 billion years to travel here, so we are seeing them when the Universe was only a ninth of its current age,” said Dr. Caitlin Casey, Hubble fellow at the UH Manoa Institute for Astronomy and lead scientist on the survey. “Now that we have a pretty good idea of how important this type of galaxy is in forming huge numbers of stars in the Universe, the next step is to figure out why and how they formed.”

A representation of the distribution of nearly 300 starbursts in one 1.4 x 1.4 degree field of view.

The galaxies, many of them observed as they were during the early stages of their formation, are producing new stars at a rate of 100 to 500 a year — with a mass equivalent of several thousand Suns — hence the moniker “starburst” galaxy. By comparison the Milky Way galaxy only births one or two Sun-mass stars per year.

The reason behind this explosion of star formation in these galaxies is unknown, but it’s thought that collisions between young galaxies may be the cause.

Another possibility is that galaxies had much more gas and dust during the early Universe, allowing for much higher star formation rates than what’s seen today.

“It’s a hotly debated topic that requires details on the shape and rotation of the galaxies before it can be resolved,” said Dr. Casey.

Still, the discovery of these “hidden” galaxies is a major step forward in understanding the evolution of star formation in the Universe.

“Our study confirms the importance of starburst galaxies in the cosmic history of star formation. Models that try to reproduce the formation and evolution of galaxies will have to take these results into account.”

– Dr. Caitlin Casey, Hubble fellow at the UH Manoa Institute for Astronomy

“For the first time, we have been able to measure distances, star formation rates, and temperatures for a brand new set of 767 previously unidentified galaxies,” said Dr. Scott Chapman, a co-author on the studies. “The previous similar survey of distant infrared starbursts only covered 73 galaxies. This is a huge improvement.”

The papers detailing the results were published today online in the Astrophysical Journal.

Sources: W.M. Keck Observatory article and ESA’s news release.

Image credits: ESA–C. Carreau/C. Casey (University of Hawai’i); COSMOS field: ESA/Herschel/SPIRE/HerMES Key Programme; Hubble images: NASA, ESA. Inset image courtesy W. M. Keck Observatory.

Orion Revisited: Astronomers Find New Star Cluster in Front of the Orion Nebula

The well-known star-forming region of the Orion Nebula.  Credit: Canada-France-Hawaii Telescope / Coelum (J.-C. Cuillandre & G. Anselmi)

Precise distances are difficult to gauge in space, especially within the relatively local regions of the Galaxy. Stars which appear close together in the night sky may actually be separated by many hundreds or thousands of light-years, and since there’s only a limited amount of space here on Earth with which to determine distances using parallax, astronomers have to come up with other ways to figure out how far objects are, and what exactly is in front of or “behind” what.

Recently, astronomers using the 340-megapixel MegaCam on the Canada-France-Hawaii Telescope (CFHT) observed the star-forming region of the famous Orion nebula — located only about 1,500 light-years away — and determined that two massive groupings of the nebula’s stars are actually located in front of the cluster as completely separate structures… a finding that may ultimately force astronomers to rethink how the many benchmark stars located there had formed.

Although the Orion nebula is easily visible with the naked eye (as the hazy center “star” in Orion’s three-star sword, hanging perpendicular below his belt) its true nebulous nature wasn’t identified until 1610. As a vast and active star-forming region of bright dust and gas located a mere 1,500 light-years distant, the various stars within the Orion Nebula Cluster (ONC) has given astronomers invaluable benchmarks for research on many aspects of star formation.

[Read more: Astrophoto – Orion’s Bloody Massacre]

Now, CFHT observations of the Orion nebula conducted by Dr. Hervé Bouy of the European Space Astronomy Centre (ESAC) and Centre for Astrobiology (CSIC) and Dr. João Alves of the Institut für Astronomie (University of Vienna) have shown that a massive cluster of stars known as NGC 1980 is actually in front of the nebula, and is an older group of approximately 2,000 stars that is separate from the stars found within the ONC… as well as more massive than once thought.

“It is hard to see how these new observations fit into any existing theoretical model of cluster formation, and that is exciting because it suggests we might be missing something fundamental.”

– Dr. João Alves, Institut für Astronomie, University of Vienna

In addition their observations with CFHT — which were combined with previous observations with ESA’s Herschel and XMM-Newton and NASA’s Spitzer and WISE — have led to the discovery of another smaller cluster, L1641W.

According to the team’s paper, “We find that there is a rich stellar population in front of the Orion A cloud, from B-stars to M-stars, with a distinct 1) spatial distribution; 2) luminosity function; and 3) velocity dispersion from the reddened population inside the Orion A cloud. The spatial distribution of this population peaks strongly around NGC 1980 (iota Ori) and is, in all likelihood, the extended stellar content of this poorly studied cluster.”

The findings show that what has been known as Orion Nebula Cluster is actually a combination of older and newer groups of stars, possibly calling for a “revision of most of the observables in the benchmark ONC region (e.g., ages, age spread, cluster size, mass function, disk frequency, etc.)”

[Read more: Astronomers See Stars Changing Right Before Their Eyes in Orion Nebula]

“We must untangle these two mixed populations, star by star, if we are to understand the region, and star formation in clusters, and even the early stages of planet formation,” according to co-author Dr. Hervé Bouy.

The team’s article “Orion Revisited” was published in the November 2012 Astronomy & Astrophysics journal. Read the CFHT press release here.

The Canada-France-Hawaii Telescope’s Mauna Kea summit dome in September 2009. Credit: CFHT/Jean-Charles Cuillandre

Inset image: Orion nebula seen in optical – where the molecular cloud is invisible – and infrared, which shows the cloud. Any star detected in the optical in the line of sight over the region highlighted in the right panel must therefore be located in the foreground of the molecular cloud. Credit: J. Alves & H. Bouy.

Star Clusters on a Clandestine Collision Course

Astronomers originally thought that just one massive star cluster shone brightly in a huge star forming region of the Tarantula Nebula, also known as 30 Doradus. But closer analysis using data from the Hubble Space Telescope shows that it is actually two different clusters that are just starting to collide and merge. A team of astronomers led by Elena Sabbi of the Space Telescope Science Institute noticed that different stars in the same region were of different ages, by at least one million years. Besides the age differences, the scientists also noticed two distinct regions, with one having the elongated “look” of a merging cluster.

“Stars are supposed to form in clusters,” said Sabbi, “but there are many young stars outside 30 Doradus that could not have formed where they are; they may have been ejected at very high velocity from 30 Doradus itself.”


Sabbi and her team were initially looking for runaway stars — fast-moving stars that have been kicked out of their stellar nurseries where they first formed.

But they noticed something unusual about the cluster when looking at the distribution of the low-mass stars detected by Hubble. It is not spherical, as was expected, but has features somewhat similar to the shape of two merging galaxies where their shapes are elongated by the tidal pull of gravity.

Some models predict that giant gas clouds out of which star clusters form may fragment into smaller pieces. Once these small pieces precipitate stars, they might then interact and merge to become a bigger system. This interaction is what Sabbi and her team think they are observing in 30 Doradus.

There are also an unusually large number of runaway, high-velocity stars around 30 Doradus, and after looking more closely at the clusters, the astronomers believe that these runaway stars were expelled from the core of 30 Doradus as the result of the dynamical interactions between the two star clusters. These interactions are very common during a process called core collapse, in which more-massive stars sink to the center of a cluster by dynamical interactions with lower-mass stars. When many massive stars have reached the core, the core becomes unstable and these massive stars start ejecting each other from the cluster.

The big cluster R136 in the center of the 30 Doradus region is too young to have already experienced a core collapse. However, since in smaller systems the core collapse is much faster, the large number of runaway stars that has been found in the 30 Doradus region can be better explained if a small cluster has merged into R136.

The entire 30 Doradus complex has been an active star-forming region for 25 million years, and it is currently unknown how much longer this region can continue creating new stars. Smaller systems that merge into larger ones could help to explain the origin of some of the largest known star clusters, Sabbi and her team said.

Follow-up studies will look at the area in more detail and on a larger scale to see if any more clusters might be interacting with the ones observed. In particular the infrared sensitivity of NASA’s planned James Webb Space Telescope (JWST) will allow astronomers to look deep into the regions of the Tarantula Nebula that are obscured in visible-light photographs. In these areas cooler and dimmer stars are hidden from view inside cocoons of dust. Webb will better reveal the underlying population of stars in the nebula.

The 30 Doradus Nebula is particularly interesting to astronomers because it is a good example of how star-forming regions in the young universe may have looked. This discovery could help scientists understand the details of cluster formation and how stars formed in the early Universe.

Science Paper by: E. Sabbi, et al. (ApJL, 2012) (PDF document)

Source: HubbleSite

Fireworks Erupt From Newborn Star

Just in time for summer fireworks season, the Hubble science team has released an image of Herbig-Haro 110, a young star with geysers of hot gas skyrocketing away through interstellar space. Twin jets of heated gas are being ejected in opposite directions from this star that is still in the formation process. The Hubble team says these outflows are fueled by gas falling onto the young star, which is surrounded by a disc of dust and gas. If the disc is the fuel tank, the star is the gravitational engine, and the jets are the exhaust. And even though the plumes of gas look like whiffs of smoke, they are actually billions of times less dense than the smoke from a fireworks display.

More information about this image from the HubbleSite:

Herbig-Haro (HH) objects come in a wide array of shapes, but the basic configuration stays the same. Twin jets of heated gas, ejected in opposite directions away from a forming star, stream through interstellar space. Astronomers suspect that these outflows are fueled by gas accreting onto a young star surrounded by a disk of dust and gas. The disk is the “fuel tank,” the star is the gravitational engine, and the jets are the exhaust.

When these energetic jets slam into colder gas, the collision plays out like a traffic jam on the interstate. Gas within the shock front slows to a crawl, but more gas continues to pile up as the jet keeps slamming into the shock from behind. Temperatures climb sharply, and this curving, flared region starts to glow. These “bow shocks” are so named because they resemble the waves that form at the front of a boat.

In the case of the single HH 110 jet, astronomers observe a spectacular and unusual permutation on this basic model. Careful study has repeatedly failed to find the source star driving HH 110, and there may be good reason for this: perhaps the HH 110 outflow is itself generated by another jet.

Astronomers now believe that the nearby HH 270 jet grazes an immovable obstacle — a much denser, colder cloud core — and gets diverted off at about a 60-degree angle. The jet goes dark and then reemerges, having reinvented itself as HH 110.

The jet shows that these energetic flows are like the erratic outbursts from a Roman candle. As fast-moving blobs of gas catch up and collide with slower blobs, new shocks arise along the jet’s interior. The light emitted from excited gas in these hot blue ridges marks the boundaries of these interior collisions. By measuring the current velocity and positions of different blobs and hot ridges along the chain within the jet, astronomers can effectively “rewind” the outflow, extrapolating the blobs back to the moment when they were emitted. This technique can be used to gain insight into the source star’s history of mass accretion.

This image is a composite of data taken with Hubble’s Advanced Camera for Surveys in 2004 and 2005 and the Wide Field Camera 3 in April 2011.

Source: HubbleSite, ESA

The Care And Feeding Of Teenage Galaxies… And By The Way, They Need Gas

Images of the six galaxies with detected inflows taken with the Advanced Camera for Surveys on the Hubble Space Telescope. Most of these galaxies have a disk-like, spiral structure, similar to that of the Milky Way. Star formation activity occurring in small knots is evident in several of the galaxies' spiral arms. Because the spirals appear tilted in the images, Rubin et al. concluded that we are viewing them from the side, rather than face-on. This orientation meshes well with a scenario of 'galactic recycling' in which gas is blown out of a galaxy perpendicular to its disk, and then falls back in at different locations along the edge of the disk. Credit: K. Rubin, MPIA

[/caption]

Got a teenager? Then you know the story. Go to look for your favorite bag of chips and they’re gone. You eat one portion of meat and they need three. If you like those cookies, then you better have a darn good place to stash them. And, while you’re at it, their car needs gas. Apparently there’s a reason for the word “universal”, because teenage galaxies aren’t much different. Thanks to some new studies done by ESO’s Very Large Telescope, astronomers have been able to take a much closer look at adolescent galaxies and their “feeding habits” during their evolution. Some 3 to 5 billion years after the Big Bang they were happiest when just provided with gas, but later on they developed a voracious appetite… for smaller galaxies!

Scientists have long been aware that early galaxy structures were much smaller than the grand spirals and hefty ellipticals which fill the present Universe. However, figuring out exactly how galaxies put on weight – and where the bulk supply comes from – has remained an enigma. Now an international group of astronomers have taken on more than a hundred hours of observations taken with the VLT to help determine how gas-rich galaxies developed.

“Two different ways of growing galaxies are competing: violent merging events when larger galaxies eat smaller ones, or a smoother and continuous flow of gas onto galaxies.” explains team leader, Thierry Contini (IRAP, Toulouse, France). “Both can lead to lots of new stars being created.”

The undertaking is is MASSIV – the Mass Assembly Survey with the VIsible imaging Multi-Object Spectrograph, a powerful camera and spectrograph on the VLT. It’s incredible equipment used to measure distance and properties of the surveyed galaxies Not only did the survey observe in the near infrared, but also employed a integral field spectrograph and adaptive optics to refine the images. This enables astronomers to map inner galaxy movements and content, as well as leaving room for some very surprising results.

“For me, the biggest surprise was the discovery of many galaxies with no rotation of their gas. Such galaxies are not observed in the nearby Universe. None of the current theories predict these objects,” says Benoît Epinat, another member of the team.

“We also didn’t expect that so many of the young galaxies in the survey would have heavier elements concentrated in their outer parts — this is the exact opposite of what we see in galaxies today,” adds Thierry Contini.

These results point towards a major change during the galactic “teenage years”. At some time during the young Universe state, smooth gas flow was a considerable building block – but mergers would later play a more important role.

“To understand how galaxies grew and evolved we need to look at them in the greatest possible detail. The SINFONI instrument on ESO’s VLT is one of the most powerful tools in the world to dissect young and distant galaxies. It plays the same role that a microscope does for a biologist,” adds Thierry Contini.

The team plans on continuing to study these galaxies with future instruments on the VLT as well as using ALMA to study the cold gas in these galaxies. However, their work with gas isn’t the only “station” on the block. In a separate study led by Kate Rubin (Max Planck Institute for Astronomy), the Keck I telescope on Mauna Kea, Hawaii, has been used to examine gas associated with a hundred galaxies at distances between 5 and 8 billion light-years – the older teens. They have found initial evidence of gas flowing back into distant galaxies that are actively forming new stars.

Images of the six galaxies with detected inflows taken with the Advanced Camera for Surveys on the Hubble Space Telescope. Most of these galaxies have a disk-like, spiral structure, similar to that of the Milky Way. Star formation activity occurring in small knots is evident in several of the galaxies' spiral arms. Because the spirals appear tilted in the images, Rubin et al. concluded that we are viewing them from the side, rather than face-on. This orientation meshes well with a scenario of 'galactic recycling' in which gas is blown out of a galaxy perpendicular to its disk, and then falls back in at different locations along the edge of the disk. Credit: K. Rubin, MPIA

Apparently, like a teenager with the munchies, matter finds its way into those galactic tummies. One feeding theory is an inflow from huge low-density gas reservoirs filling the intergalactic voids… another is huge cosmic matter cycle. While there is very little evidence to support either hypothesis, gases have been observed to flow away from some galaxies and may be moshed around by several different sources – such as supernovae events or peer pressure from gigantic stars.

“As this gas drifts away, it is pulled back by the galaxy’s gravity, and could re-enter the same galaxy in time scales of one to several billion years. This process might solve the mystery: the gas we find inside galaxies may only be about half of the raw material that ends up as fuel for star formation.” says Dr. Rubin. “Large amounts of gas are caught in transit, but will re-enter the galaxy in due time. Add up the galaxy’s gas and the gas currently undergoing cosmic recycling, and there is a sufficient amount of raw matter to account for the observed rates of star formation.”

It might very well be a case of cosmic recycling… but I’d feel safer hiding my cookies.

Original Story Sources: ESO News Release and MPIA Science News Release. For Further Reading: Research Paper 1, Research Paper 2, Research Paper 3 and Research Paper 4.

Astronomers See Stars Changing Right Before Their Eyes in Orion Nebula

This new view of the Orion nebula highlights fledging stars hidden in the gas and clouds. Image credit: NASA/ESA/JPL-Caltech/IRAM

[/caption]

A gorgeous new image from the tag team effort of the Herschel and Spitzer Space telescopes shows a rainbow of colors within the Orion nebula. The different colors reflect the different wavelengths of infrared light captured by the two space observatories, and by combining their observations, astronomers can get a more complete picture of star formation. And in fact, astronomers have spotted young stars in the Orion nebula changing right before their eyes, over a span of just a few weeks!

Astronomers with Herschel mapped this region of the sky once a week for six weeks in the late winter and spring of 2011. Notice the necklace of stars strung across the middle of the image? Over just that short amount of time, a discernible change in the stars took place as they appeared to be rapidly heating up and cooling down. The astronomers wondered if the stars were actually maturing from being star embryos, moving towards becoming full-fledged stars.

To monitor for activity in protostars, Herschel’s Photodetector Array Camera and Spectrometer stared in long infrared wavelengths of light, tracing cold dust particles, while Spitzer took a look at the warmer dust emitting shorter infrared wavelengths. In this data, astronomers noticed that several of the young stars varied in their brightness by more than 20 percent over just a few weeks.

As this twinkling comes from cool material emitting infrared light, the material must be far from the hot center of the young star, likely in the outer disk or surrounding gas envelope. At that distance, it should take years or centuries for material to spiral closer in to the growing starlet, rather than mere weeks.

The astronomers said a couple of scenarios could account for this short span. One possibility is that lumpy filaments of gas funnel from the outer to the central regions of the star, temporarily warming the object as the clumps hit its inner disk. Or, it could be that material occasionally piles up at the inner edge of the disk and casts a shadow on the outer disk.

“Herschel’s exquisite sensitivity opens up new possibilities for astronomers to study star formation, and we are very excited to have witnessed short-term variability in Orion protostars,” said Nicolas Billot, an astronomer at the Institut de Radioastronomie Millimétrique (IRAM) in Grenada, Spain who is preparing a paper on the findings along with his colleagues. “Follow-up observations with Herschel will help us identify the physical processes responsible for the variability.”

Source: NASA

Young Star Cluster In Disintegrated Galaxy Reveals First-Ever Intermediate Mass Black Hole

This spectacular edge-on galaxy, called ESO 243-49, is home to an intermediate-mass black hole that may have been stripped off of a cannibalized dwarf galaxy. Credit: NASA, ESA, and S. Farrell (Sydney Institute for Astronomy, University of Sydney)

[/caption]

Score another first for NASA’s Hubble Space Telescope! Along with observations taken with the Swift X-ray telescope, a team of astronomers have identified a young stellar cluster of stars pointing the way towards the first verified intermediate mass black hole. This grouping of stars provides significant indication that black holes of this type may have been at the center of a now shredded dwarf galaxy – a finding which increases our knowledge of galaxy evolution.

“For the first time, we have evidence on the environment, and thus the origin, of this middle-weight black hole,” said Mathieu Servillat, a member of the Harvard-Smithsonian Center for Astrophysics research team.

Designated as ESO 243-49 HLX-1, this incredible intermediate mass black hole was discovered in 2009 by Sean Farrell, of the Sydney Institute for Astronomy in Australia, using the European Space Agency’s XMM-Newton X-ray space telescope. Hyper-Luminous X-ray Source 1 is a 20,000 solar mass beauty which resides at the edge of galaxy ESO 243-49 some 290 million light years away. However, the Newton’s findings weren’t the only contribution – HLX-1 was also verified with NASA’s Swift observatory in X-ray and Hubble in near-infrared, optical, and ultraviolet wavelengths. What stands out is the presence of a cluster of young stars encircling the black hole and stretching out across about 250 light years of space. While the stars themselves are too far away to be resolved, their magnitude and spectra match with other young clusters seen in similar galaxies.

Just what clued the team to the presence of a star cluster? In this case their instruments revealed the blue spectrum of hot gases being emitted from the accretion disk located at the periphery of the black hole… and there was more. They also noted the presence of red light spawned by cooler gases which may indicate the presences of stars. Time to match up the findings against computer modeling.

“What we can definitely say with our Hubble data is that we require both emission from an accretion disk and emission from a stellar population to explain the colors we see.” said Farrell.

Why is the presence of a young star cluster unusual? According to what we know so far, they just don’t occur outside a flattened disk such as HLX-1. This finding may indicate the intermediate mass black hole may have once been at the heart of a dwarf galaxy engaged in a merger event. The dwarf galaxy’s stars were stripped away, but not its capabilities to form new. During the interaction, the gas around the black hole was compressed and star formation began again… but how long ago?

“The age of the population cannot be uniquely constrained, with both very young and very old stellar populations allowed. However, the very old solution requires excessively high levels of disc reprocessing and an extremely small disc, leading us to favour the young solution with an age of ~13 Myr.” says the team. “In addition, the presence of dust lanes and the lack of any nuclear activity from X-ray observations of the host galaxy lead us to propose that a gas-rich minor merger may have taken place less than ~200 Myr ago. Such a merger event would explain the presence of the intermediate mass black hole and support a young stellar population.”

Discoveries such as HLX-1 will help astronomers further understand how supermassive black holes are formed. Current conjecture is that intermediate mass black holes may migrate together to form their larger counterparts. Studying the trajectory of this new find may provide valuable information… even if it is unknown at this point. HLX-1 may be drawn into a merger event and it may just end up orbiting ESO 243-49. Regardless of what happens, chances are it will fade away in X-ray as it exhausts its gas supply.

“This black hole is unique in that it’s the only intermediate-mass black hole we’ve found so far. Its rarity suggests that these black holes are only visible for a short time,” said Servillat.

Original Story Source: Harvard Center for Astrophysics News Release. For Further Reading: A Young Massive Stellar Population Around the Intermediate Mass Black Hole ESO 243-49 HLX-1.

‘Dark Markings of the Sky’ are Hiding Star Formation

This image from the APEX telescope, of part of the Taurus Molecular Cloud, shows a sinuous filament of cosmic dust more than ten light-years long. Could life exist in molecular clouds like this one? Credit: ESO/APEX (MPIfR/ESO/OSO)/A. Hacar et al./Digitized Sky Survey 2. Acknowledgment: Davide De Martin.

[/caption]

This stunning new image shows a sinuous filament of cosmic dust more than ten light-years long. The makeup of filamentary cloud structures like this used to be a mystery, and in the early 20th century, Edward Emerson Barnard compiled a photographic atlas of these features, calling them “dark markings of the sky,” as these regions appeared as dark lanes, with no stars visible. Barnard correctly argued that this appearance was due to “obscuring matter in space.” Today we call segments in this particular cloud Barnard 211 and Barnard 213, or the Taurus Molecular Cloud. And we now know that these are clouds of interstellar gas and dust grains. But also, within these clouds, newborn stars are hidden, and dense clouds of gas are on the verge of collapsing to form yet more stars.

The Taurus Molecular Cloud is one of the closest regions of star formation to us. It is located in the constellation of Taurus about 450 light-years from Earth. The cosmic dust grains are so cold that observations at wavelengths of around one millimeter, such as these made with the LABOCA camera on APEX (Atacama Pathfinder Experiment) telescope in Chile, are needed to detect their faint glow.

This image shows two parts of a long filament. The dust grains — tiny particles similar to very fine soot and sand — absorb visible light, blocking our view of the rich star field behind the clouds. The Taurus Molecular Cloud is particularly dark at visible wavelengths, as it lacks the massive stars that illuminate the nebulae in other star-formation regions such as Orion.

But active star formation is taking place. This is why observations at longer wavelengths, such as the millimeter range, are essential for understanding the early stages of star formation.

Read more about this particular region at the ESO website.