Posted on by Tammy Plotner

Cosmic Collisions Could Eject Habitable Planets

One of 42 new proplyds discovered in the Orion Nebula, 177-341E is one of the bright proplyds that lies relatively close to the nebula’s brightest star, Theta 1 Orionis C. The tadpole-shaped tail is actually a jet of matter flowing away from the excited cusp. Credit:NASA/ESA and L. Ricci (ESO)

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When it comes to solar systems, chances are good that we’re a lot more special than we thought. According to a German-British team led by Professor Pavel Kroupa of the University of Bonn, our orderly neighborhood of varied planet sizes quietly orbiting in a nearly circular path isn’t a standard affair. Their new models show that habitable planets might just get ejected in a violent scenario where forming solar systems mean highly inclined orbits where hot Jupiters rule.

Some 4600 million years ago, our local planetary system was surmised to have evolved from a blanket of dust surrounding a rather ordinary star. Its planets orbited the same direction as the solar spin and lined up neatly on a plane fairly close to the solar equator. We were good little children… But maybe other systems aren’t so hospitable. There could be systems where the planets cruise around in the opposite direction of their host star’s spin – and have highly inclined orbits. What could cause one protoplanetary disk to take on quiet properties while another is more radical? Try a cosmic crash.

This new study focuses on the theory of a protoplanetary disk colliding with another cloud of material… not unrealistic thinking since most stars form within a cluster. The results could mean the inclusion of up to thirty times the mass of Jupiter. This added “weight” of extra gas and dust could add a tilt to a forming system. Team member Dr Ingo Thies, also of the University of Bonn, has carried out computer simulations to test the new idea. What he has found is that adding extra material can not only incline a forming disk, but cause a reverse spin as well. It may even speed up the planetary formation, leaving the rogues in retrograde orbits. This inhospitable scenario means that smaller planets get ejected systematically, leaving only hot Jupiters to hug in close to the parent star. Thankfully our path was a bit less disturbing.

Says Dr Thies: “Like most stars, the Sun formed in a cluster, so probably did encounter another cloud of gas and dust soon after it formed. Fortunately for us, this was a gentle collision, so the effect on the disk that eventually became the planets was relatively benign. If things had been different, an unstable planetary system may have formed around the Sun, the Earth might have been ejected from the Solar System and none of us would be here to talk about it.”

Professor Kroupa sees the model as a big step forward. “We may be on the cusp of solving the mystery of why some planetary systems are tilted so much and lack places where life could thrive. The model helps to explain why our Solar System looks the way it does, with the Earth in a stable orbit and larger planets further out. Our work should help other scientists refine their search for life elsewhere in the Universe.”

Original News Source: Royal Astronomical Society News.

Posted on by Tammy Plotner

Rewriting Lunar History

NASA Science News Lunar Image Credt: Sylvain Weiller

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We thought we knew everything there was to know about our Moon, but new investigations into its volcanic origins are causing scientists to take another look at how our nearest astronomical neighbor formed – and its age. If you like a little lunacy in your life, then step inside and read more…

A team of scientists led by Carnegie’s Erik Hauri have been busy studying seven tiny Apollo 17 return samples with a a state-of-the-art NanoSIMS 50L ion microprobe. These little pieces of lunar “evidence” are fragments of lunar magma which contain crystals called “melt inclusions”. High in titanium content, these crystals were once a part of volcanic glass beads ejected in explosive volcanic eruptions. The cool part is these melt inclusions coughed up from the lunar depths eons ago yielded a discovery – the magma trapped within crystals show a hundred times more water than once believed.

“In contrast to most volcanic deposits, the melt inclusions are encased in crystals that prevent the escape of water and other volatiles during eruption. These samples provide the best window we have to the amount of water in the interior of the Moon,” said James Van Orman of Case Western Reserve University, a member of the science team. The paper’s authors are Hauri; Thomas Weinreich, Alberto Saal and Malcolm Rutherford from Brown University; and Van Orman.

As meteorite fans well know, water content is everything and the inner Solar System was nearly devoid of it and other volatile elements during early formation. Past lunar studies show an even lower content, supporting the giant impactor theory – a theory which could very well need to be reconsidered. New findings also point to the need for more sample returns from other Solar System bodies as well.

“Water plays a critical role in determining the tectonic behavior of planetary surfaces, the melting point of planetary interiors, and the location and eruptive style of planetary volcanoes,” said Hauri, a geochemist with Carnegie’s Department of Terrestrial Magnetism (DTM). “We can conceive of no sample type that would be more important to return to Earth than these volcanic glass samples ejected by explosive volcanism, which have been mapped not only on the Moon but throughout the inner Solar System.”

But this isn’t a first for Saal. Three years ago the same team reported the first evidence for the presence of water in lunar volcanic glasses. Using modeling, they were able to theorize how much water was contained within the magma before eruption. From those results, Weinreich, a Brown University undergraduate, found the melt inclusions. This permitted the team to measure the pre-eruption concentration of water in the magma and estimate the amount of water in the Moon’s interior.

“The bottom line,” said Saal, “is that in 2008, we said the primitive water content in the lunar magmas should be similar to the water content in lavas coming from the Earth’s depleted upper mantle. Now, we have proven that is indeed the case.”

Of course, this could mean changing scientific thought on where lunar pole ice deposits originated, too. Current theory suggests they are the product of comets and meteoroid impacts – but perhaps they also could be magma related. It’s a fascinating study which could also help us to understand the properties of other planetary bodies.

But the magma doesn’t stop there…

According to new research from a team that includes Carnegie’s Richard Carlson and former-Carnegie fellow Maud Boyet, magma samples might be revealing a younger Moon, too. Building on the giant impactor theory, samples of a rock type called ferroan anorthosite, or FAN, are being examined. Believed to be the oldest of the Moon’s crustal rocks, FAN could be as old as 4.36 billion years – a figure much younger than previous lunar estimates. Using isotopes of the elements lead and neodymium, the team analyzed the samples for consistent ages from multiple isotope dating techniques.

“The extraordinarily young age of this lunar sample either means that the Moon solidified significantly later than previous estimates, or that we need to change our entire understanding of the Moon’s geochemical history,” Carlson said.

What does all this mean? Thanks to our understanding of the oldest terrestrial minerals, such as zircons from western Australia, we can derive the Moon’s crust may have evolved at the same time as Earth’s… a time which could date back to a giant impact. “The Earth’s Moon is the archetypical example of this type of differentiation.” says the team. “Evidence for a lunar magma ocean is derived largely from the widespread distribution, compositional and mineralogical characteristics, and ancient ages inferred for the ferroan anorthosite (FAN) suite of lunar crustal rocks.”

The next time you observe the Moon, remember… she’s a bit younger than you thought!

Original News Source: Carnegie Science News and Science Daily.

Posted on by Tammy Plotner

The Lyman-Alpha Blob That Ate The Universe…

Observations from ESO’s Very Large Telescope have shed light on the power source of a rare vast cloud of glowing gas in the early Universe. The observations show for the first time that this giant “Lyman-alpha blob” — one of the largest single objects known — must be powered by galaxies embedded within it. The results appear in the 18 August issue of the journal Nature. Credit: ESO

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It’s called a Lyman-alpha blob and it’s one of the largest known single objects in the Universe. It first made its presence known in the year 2000 and we know it’s located some 11.5 billion light years away. What will really get your attention is the size. LAB-1 has a diameter of about 300,000 light-years across!

Utilizing ESO’s Very Large Telescope (VLT), a team of astronomers were checking out areas of the early Universe where matter was the most dense – home to huge and very luminous rare structures called Lyman-alpha blobs. While there wasn’t anything in particular they were looking for, what they captured was something unique… evidence of polarization.

“We have shown for the first time that the glow of this enigmatic object is scattered light from brilliant galaxies hidden within, rather than the gas throughout the cloud itself shining.” explains Matthew Hayes (University of Toulouse, France), lead author of the paper.

These super-sized clouds of hydrogen gas stagger the imagination with their sheer dimensions. Some reach diameters of a few hundred thousand light-years – large enough to enfold the Milky Way three times over – and are as luminous as the most powerful galaxy we can observe. Since Lyman-alpha blobs are located so far away, we can only see them as they were when the Universe was a few billion years old, but they have a lot to teach us about their origins. Some theories suggest they shine when cool gas is pulled in by the blob’s powerful gravity and heated. Other conjectures are they are illuminated from within – lit by extreme star-forming events, supernovae or hungry black holes swallowing matter.

Thanks to these recent studies, the latest idea is the illumination comes from embedded galaxies. How do astronomers know this? By measuring whether the light from the blob was polarized. By measuring the physical processes that produced the light with sensitive equipment, researchers can gain insight from scattering or reflecting properties. However, the task hasn’t been easy considering the great distance of Lyman-alpha blobs.

“These observations couldn’t have been done without the VLT and its FORS instrument. We clearly needed two things: a telescope with at least an eight-metre mirror to collect enough light, and a camera capable of measuring the polarisation of light. Not many observatories in the world offer this combination.” adds Claudia Scarlata (University of Minnesota, USA), co-author of the paper.

According to ESO, the team observed their target for about 15 hours with the Very Large Telescope, and the light from the Lyman-alpha blob LAB-1 showed a centralized ring of polarization – but no central polarized spot. “This effect is almost impossible to produce if light simply comes from the gas falling into the blob under gravity, but it is just what is expected if the light originally comes from galaxies embedded in the central region, before being scattered by the gas. The astronomers now plan to look at more of these objects to see if the results obtained for LAB-1 are true of other blobs.”

Before they find us…

Original Story Source: ESO Science News Release.

Posted on by Tammy Plotner

Capture Comet C2009 P1 Garradd Now

Comet C2009 P1 Garradd and Perseids imaged by students at Bareket Observatory.

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What are you waiting for? If it’s an engraved invitation, then consider this your pass to get out and start looking for Comet C/2009 P1 Garradd! It’s well within reach of average binoculars and it’s even in a position that’s easy for the average observer! Step on out here into the backyard and I’ll show you…

At close to magnitude 8, Comet C/2009 P1 Garradd is currently grazing its way along the eastern line of the Summer Triangle. Even if you live in a moderately light polluted area, you should be able to make out the three bright stars, Deneb to the north, Vega to the west and Altair to the south. Just aim your binoculars roughly halfway between Altair and Deneb and begin scanning on binocular field at a time for a faint, fuzzy poofball that signifies the comet’s presence. What you will see in binoculars will appear to be like a “fuzzy star” – while a telescope will reveal the beginnings of a tail.

Just check out the video taken by our friends at Bareket Observatory!

Did you catch the signature of a Perseid meteor in there, too? Good for you!

Now quit messing around on the computer and get out there and capture that comet!

Thanks to Bareket Observatory for the images and to heavens-above.com for the locator chart!

Posted on by Tammy Plotner

Geodesy Is Alive And Well… And Splitting Hairs On Planet Earth

This view of Earth comes from NASA's Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite. Image credit: NASA

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When it comes to planet Earth, it’s very important to know if we’re growing or shrinking. While plate tectonics are responsible for major changes in our planet’s outer crust, we need to have accurate measurements of our atmosphere and magnetic fields, too. To make these appraisals accurate, the global science community established the International Terrestrial Reference Frame.

At one time scientists theorized that Earth might be expanding or contracting. After all, major events like volcanoes, landslides and ice sheets were at the root of significant elevation changes. Even sizable climate events like El Nino and La Nina are responsible for redistributing large amounts of water. Now a new NASA study, published recently in Geophysical Research Letter, has pointed towards the utilization of space measurement tools and a new data calculation techniques which show no vital changes in the size of our planet.

Why is monitoring our size so important? The International Terrestrial Reference Frame is not only important for ground navigation, but satellite tracking as well. NASA says to think of it this way: “If all of Earth’s GPS stations were located in Norway, their data would indicate that Earth is growing, because high-latitude countries like Norway are still rising in elevation in response to the removal of the weight of Ice Age ice sheets.” So for all intents and purposes, the ITRF uses the average center of mass of the total Earth, a computation of a quarter of a century of satellite data. High-precision space geodesy includes:

  • Satellite Laser Ranging — a global observation station network that measures, with millimeter-level precision, the time it takes for ultrashort pulses of light to travel from the ground stations to satellites specially equipped with retroreflectors and back again.
  • Very-Long Baseline Interferometry — a radio astronomy technology that combines observations of an object made simultaneously by many telescopes to simulate a telescope as big as the maximum distance between the telescopes.
  • Global Positioning System — the U.S.-built space-based global navigation system that provides users around the world with precise location and time information.
  • Doppler Orbitography and Radiopositioning Integrated by Satellite — a French satellite system used to determine satellite orbits and positioning. Beacons on the ground emit radio signals that are received by satellites. The movement of the satellites causes a frequency shift of the signal that can be observed to determine ground positions and other information.

A team of scientists led by Xiaoping Wu of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., and including participants from the Institut Geographique National, Champs-sur-Marne in France, and Delft University of Technology in The Netherlands are currently busy assessing the accuracy of the International Terrestrial Reference Frame. Through the use of the new data and calculation techniques combined with measurements of Earth’s gravity from NASA’s Gravity Recovery and Climate Experiment (GRACE) spacecraft and models of ocean bottom pressure, they are even able to account for minute changes in Earth’s gravity. The resultant changes have shown Earth’s radius to vary about 0.004 inches (0.1 millimeters) – or less than the thickness of a human hair.

“Our study provides an independent confirmation that the solid Earth is not getting larger at present, within current measurement uncertainties,” said Wu.

Original Story Source: JPL News.

Posted on by Tammy Plotner

Ring Of Anti-Protons Found Encircling Earth

PAMELA team and detector in Rome before launch. Photo courtesy of the PAMELA Experiment

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When it comes to planets with rings, we know the answer: Jupiter, Saturn, Uranus, and Neptune. But new findings from the PAMELA experiment show that Earth has a ring system, too… One made up of geomagnetically trapped cosmic ray antiprotons.

“The existence of a significant flux of antiprotons confined to Earth’s magnetosphere has been considered in several theoretical works.” says team leader, O. Adriani of the University of Florence Department of Physics. “These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers.”

The PAMELA experiment – short for Payload for Antimatter Exploration and Light-nuclei Astrophysics – is based on an international collaboration involving about 100 physicists. Its state-of-the-art equipment was designed to investigate the nature of dark matter, the apparent absence of cosmological antimatter and the origin and evolution of matter in the galaxy. Utilizing a permanent magnet spectrometer with a variety of specialized detectors, PAMELA whips around Earth on a highly inclined orbit.

“The satellite orbit (70 degree inclination and 350–610 km altitude) allows PAMELA to perform a very detailed measurement of the cosmic radiation in different regions of Earth’s magnetosphere, providing information about the nature and energy spectra of sub-cutoff particles.” says Adriani. “The satellite orbit passes through the South Atlantic Anomaly (SAA), allowing the study of geomagnetically trapped particles in the inner radiation belt.”

From its subdetectors, PAMELA dished up a serving of antiprotons, but it wasn’t an easy job. “Antiprotons in the selected energy range are likely to annihilate inside the calorimeter, thus leaving a clear signature.” says the team. “The longitudinal and transverse segmentation of the calorimeter is exploited to allow the shower development to be characterized. These selections are combined with dE/dx measurements from individual strips in the silicon detector planes to allow electromagnetic showers to be identified with very high accuracy.”

For 850 days, the detectors collected data and compared it against simulations. The trapped antiprotons were highly dependent on angular collection, directional response function on the satellite orbital position and on its orientation relative to the geomagnetic field. “All the identified antiprotons, characterized by a pitch angle near 90 deg, were found to spiral around field lines, bounce between mirror points, and also perform a slow longitudinal drift around the Earth, for a total path length amounting to several Earth radii.” said the team. “PAMELA results allow CR transport models to be tested in the terrestrial atmosphere and significantly constrain predictions from trapped antiproton models, reducing uncertainties concerning the antiproton production spectrum in Earth’s magnetosphere.”

Original Story Source: Astrophysical Journal Newsletters.

Posted on by Tammy Plotner

White Dwarf Stars Consume Rocky Bodies

This artist's concept shows a star encircled by a disk of gas and dust, the raw materials from which rocky planets such as Earth are thought to form. Image credit: NASA/JPL-Caltech

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“I love rocky road… So won’t you buy another gallon, baby…” Yeah. We all love rocky road ice cream, but what do stars like to snack on? In the case of the white dwarf star it would appear that a rocky body – similar to Earth – could be a preferred blend. At one time astronomers thought the dense, elderly stars were just gathering dust… but apparently it’s the “bones” left-over from a planetary knosh.

Using the Keck I telescope on Mauna Kea in Hawaii, astronomer and study coauthor Ben Zuckerman of UCLA and his team have been studying two helium-dominated white dwarfs – stars PG1225-079 and HS2253+8023. About the size of Earth, but as massive as the Sun, these stars have a zone of “pollution” around them that’s around equal in mass to asteroid Ceres.

“This means that planet-like rocky material is forming at Earth-like distances or temperatures from these stars,” says Zuckerman. He also notes that it’s still unclear whether the material is from a planet, planet-like bodies or an asteroid, but it is clear that there’s a lot of it.

Because looking at a white dwarf star for evidence of solar systems wasn’t really a high priority consideration, these new findings could lend researchers some new clues. It’s not just dust – it’s dust with a signature. Because the white dwarf has a “clean” atmosphere of hydrogen or helium, finding other components in its spectra could point to a one-time presence of Earth-like planets. Zuckerman says that between 25 and 30 percent of white dwarfs have orbital systems that contain both large planets and smaller rocky bodies. After the dwarf forms, larger, Jupiter-mass planets can perturb the orbits of smaller bodies and bounce them toward the star.

“This is the first hint that despite all the oddball planetary systems we see, some of them must be more like our own,” says astronomer John Debes of NASA’s Goddard Space Flight Center in Greenbelt, Md., who was not involved in the study. “We think that most of these systems that show pollution must in some way approximate ours.”

How do they know if they have a candidate? Star PG1225-079 has a mix of elements, including magnesium, iron and nickel (along with others). These were found in ratios very similar in overall content of Earth. Star HS2253+8023 contains more than 85 percent oxygen, magnesium, silicon and iron. Not only are these assessments also similar to our planet, but found in the correct range where this type of rocky body should have formed.

“I’ve never seen so much detail in spectra,” says astronomer Jay Holberg of the University of Arizona in Tucson, who was not involved in the study. “People have seen iron and calcium and other things in these stars, but [this group has] gone off and found a whole slew of other elements.”

Pass the spoon… Before it melts.

Original Story Source: Science News Release.

Posted on by Tammy Plotner

Pardon Me, But Your Black Hole Is Leaking…

Gaia BH1 is a Sun-like star co-orbiting with a black hole estimated at 10 times the Sun's mass. Credit: ESO/L. Calcada

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Yes. We thought we knew everything there was to know about black holes. We know they are massive and compact. We know they possess a gravity so intense that it even bends “space time”. We know they won’t even allow light to escape. But what we weren’t really prepared for is that our human line of reasoning might be wrong. Black holes might consume everything… But they leak information.

Thanks to a new study done by Professor Samuel Braunstein and Dr Manas Patra of the University of York, we just might need to realign our way of thinking about black holes and one of the most fundamental forces of Nature – gravity. Professor Braunstein says: “Our results didn’t need the details of a black hole’s curved space geometry. That lends support to recent proposals that space, time and even gravity itself may be emergent properties within a deeper theory. Our work subtly changes those proposals, by identifying quantum information theory as the likely candidate for the source of an emergent theory of gravity.”

Are your quantum mechanics a bit rusty? Then blame a few holes in these theories. “This vision was motivated in part by Jacobson’s 1995 surprise result that the Einstein equations of gravity follow from the thermodynamic properties of event horizons.” says the team. “Taking a first tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole event horizons in a spacetime-free manner. Our result relies on a Hilbert space description of black hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes, global conservation of the no-hair quantities, and the existence of Penrose processes. Our analysis is not wedded to standard general relativity and so should apply to extended gravity theories where we find that the black hole area must be replaced by some other property in any generalized area theorem.”

Like your elderly neighbor whose curtains twitch each time you take your telescope into the yard at night and hastens to grab the telephone to tell other neighbors, information can leak from a black hole. The neighbor knows you’re out there… And soon enough, the rest of the neighbors know as well. Professor Braunstein says: “Our results actually extend the predictions made by well-established techniques that rely on a detailed knowledge of space time and black hole geometry.”

Dr Patra adds: “We cannot claim to have proven that escape from a black hole is truly possible, but that is the most straight-forward interpretation of our results. Indeed, our results suggest that quantum information theory will play a key role in a future theory combining quantum mechanics and gravity.”

For Further Reading: Black Hole Evaporation Rates without Spacetime. Original News Source: University of York News Release.

Posted on by Tammy Plotner

Graphenes In Spaaaaaace!

Artist’s impression of the graphenes (C24) and fullerenes found in a Planetary Nebula. The detection of graphenes and fullerenes around old stars as common as our Sun suggests that these molecules and other allotropic forms of carbon may be widespread in space. Credits: IAC; original image of the Helix Nebula (NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner, STScI, & T.A. Rector, NRAO.)

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And just where have your buckyballs been lately? More technically known as fullerenes, this magnetic form of carbon shows some pretty interesting properties deduced from laboratory work here on Earth. But even more interesting is its cousin – graphene. And guess where it’s been found?!

When you picture a fullerene, you conjure up a mental image of carbon atoms arranged in a three-dimensional configuration with two structures: C60 which patterns out similar to a soccer ball and C70 which more closely resembles a rugby ball. Both of these types of “buckyballs” have been detected in space, but the real kicker is graphene. Its technical name is planar C24 and instead of being geodesic, it’s the thinnest substance known. Just one atom thick, this flat sheet of carbon is a portrait in extraordinary strength, conductivity and elasticity. Graphene was first synthesized in the lab in 2004 and now planar C24 may have been detected in space.

Through the use of the Spitzer Space Telescope, a team of astronomers led by Domingo Aníbal García-Hernández of the Instituto de Astrofísica de Canarias in Spain have not only picked up a C70 fullerene molecule, but may have also detected graphene as well. “If confirmed with laboratory spectroscopy – something that is almost impossible with the present techniques – this would be the first detection of graphene in space” said García-Hernández.

Letizia Stanghellini and Richard Shaw, members of the team at the National Optical Astronomy Observatory in Tucson, Arizona suspect collisional shocks generated in stellar winds of planetary nebulae could be responsible for the presence of fullerenes and graphenes through the destruction of hydrogenated amorphous carbon grains (HACs). “What is particularly surprising is that the existence of these molecules does not depend on the stellar temperature, but on the strength of the wind shocks” says Stanghellini.

So where has this discovery taken place? Try the Magellanic Clouds. In this case, using a planetary nebula “closer to home” is not part of the equation because science needs to be certain the material they are looking at is indeed the by-product of a planetary nebula and not a mix. Fortunately the SMG is known to be metal-poor, which enhances the chances of spotting complex carbon molecules. Right now the challenge has been to pinpoint the evidence for graphene from Spitzer data.

“The Spitzer Space Telescope has been amazingly important for studying complex organic molecules in stellar environments” says Stanghellini. “We are now at the stage of not only detecting fullerenes and other molecules, but starting to understand how they form and evolve in stars.” Shaw adds “We are planning ground-based follow up through the NOAO system of telescopes. We hope to find other molecules in planetary nebulae where fullerene has been detected to test some physical processes that might help us understand the biochemistry of life.”

Original News Source: National Optical Astronomy Observatory News Release.

Posted on by Tammy Plotner

Red-Burning Galaxies… Let’s Get The Party Started!

An image illustrating the number density of galaxies estimated to be four billion light years from the Earth. Bright areas indicate high-density regions. The brightest region in the center corresponds to the main body of the CL0939 cluster. Red squares show the positions of the red -burning galaxies while the greenish-blue dots show the blue H? emitting galaxies. Evidently, the red burning galaxies avoid the central region of the cluster and concentrate in small groups located far away from it.

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Utilizing the Subaru Telescope, a research team of astronomers from the University of Tokyo and the National Astronomical Society of Japan (NAOJ) used a wide-field image to take a look four billion years back in time. The object of their interest was a galaxy cluster, but what really took their fancy wasn’t the old matrons – it was the red star-forming galaxies hanging around the edges.

Just exactly what is a “red-burning galaxy”? Astronomers hypothesize they might be the transitional key between the young and old… and present at a party that shows dramatic evolution. It’s not the fact that such galaxies exist within galactic clusters, but why they seem to appear along the outskirts.

When galaxies first began forming under the weight of their own gravity some ten billion years ago, they either became part of big clusters or small groups. As they came together, they took on properties of their environment – just as party goers tend to group together where interests are similar. At a galactic get-together with high density, galaxies form into lenticular or elliptical, while the solitary wall flowers tend toward spiral structure. But exactly how they form and evolve is one of astronomy’s greatest enigmas.

A panoramic view of the CL0939+4713 cluster located 4 billion light years away from Earth. Images were captured with the Subaru Prime Focus Camera (Suprime-Cam), all of which are a composite of a B-band image (blue), a R-band image (green), and a z'-band image (red). Left 27 arcmin x 27 arcmin field of view. Top-right: Close-up view of the central cluster region, 2.5 arcmin x 2.5 arcmin field of view. Bottom-right: Example of the concentration of red-burning galaxies, which are marked with red squares.

To help solve the mystery, researchers are looking further back into the past. A research team led by Dr. Yusei Koyama used the Subaru Prime Focus Camera (Suprime-Cam) to carry out a panoramic observation targeting a relatively well-known rich cluster, CL0939+4713. By using a special filter that separates the hydrogen-alpha emission lline Koyama’s team members identified more than 400 galaxies showing a narrowband excess which could denote the star formation process. Strangely enough, it was these very galaxies that showed an impressive amount of red and were located in groups well away from the main body.

Needless to say, this opened the door to even more questions. Where did they come from and why are they concentrated in groups and not clusters? At this point, who knows? Astronomers are positive the “red-burning galaxies” get their properties from starbirth – not elderly populations. They also anticipate the main galaxy cluster will one day absorb these strays into the main body as well. How can they tell? Just like the party, the red-burning galaxies are already changing in relationship to their environment. Older galaxies that no longer have active star-forming regions seem to be increasing in the groups, exactly where the red-burners are most frequently found.

“This suggests that the red-burning galaxies are related to the increase in old galaxies, and that they are likely to be in a transitional phase from a younger to an older generation. The finding that such transitional galaxies are located most frequently within group environments shows that galaxy groups are the key environments for understanding how environment shapes the evolution of galaxies.” says the Subaru research team. “This should be an important and exciting step toward a more complete understanding of the environments shaping the galaxies in the present-day Universe.”

Party on, dudes…

Original Story Source: Subaru Telescope Press Release.