Powerful Starbursts in Dwarf Galaxies Helped Shape the Early Universe, a New Study Suggests

GOODS field containing distant dwarf galaxies forming stars at an incredible rate. Image Credit: ESO

Massive galaxies in the early Universe formed stars at a much faster clip than they do today — creating the equivalent of a thousand new suns per year. This rate reached its peak 3 billion years after the Big Bang, and by 6 billion years, galaxies had created most of their stars.

New observations from the Hubble Space Telescope show that even dwarf galaxies — the small, low mass clusters of several billion stars — produced stars at a rapid rate, playing a bigger role than expected in the early history of the Universe.

Today, we tend to see dwarf galaxies clinging to larger galaxies, or sometimes engulfed within, rather than existing as blazing collections of stars alone. But astronomers have suspected that dwarfs in the early Universe could turn over stars quickly. The trouble is, most images aren’t sharp enough to reveal the faint, faraway galaxies we need to observe.

“We already suspected that dwarf starbursting galaxies would contribute to the early wave of star formation, but this is the first time we’ve been able to measure the effect they actually had,” said lead author Hakim Atek of the École Polytechnique Fédérale de Lausanne (EPFL) in a press release. “They appear to have had a surprisingly significant role to play during the epoch where the Universe formed most of its stars.”

Previous studies of starburst galaxies in the early Universe were biased toward massive galaxies, leaving out the huge number of dwarf galaxies that existed in this era. But the highly sensitive capabilities of Hubble’s Wide Field Camera 3 have now allowed astronomers to peer at low-mass dwarf galaxies in the distant Universe.

This image represents the data that comes from using the NASA/ESA Hubble Space Telescop's highly-sensitive Wide Field Camera 3 in its grism spectroscopy mode. A grism is a combination of a grating and a prism, and it splits up the light from a galaxy into its constituent colours, producing a spectrum. In this image the continuum of each galaxy is shown as a "rainbow". Astronomers can look at a galaxy’s spectrum and identify light emitted by the hydrogen gas in the galaxy. If there are stars being formed in the galaxy then the intense radiation from the newborn stars heats up the hydrogen gas and makes it glow. All of the light from the hydrogen gas is emitted in a small number of very narrow and bright emission lines. For dwarf galaxies in the early Universe the emission lines are much easier to detect than the faint, almost invisible, continuum.  Image Credit: NASA and ESA
This image represents the data that comes from using the NASA/ESA Hubble Space Telescope’s highly-sensitive Wide Field Camera 3 in its grism spectroscopy mode. Image Credit: NASA / ESA

Atek and colleagues looked at 1000 galaxies from roughly three billion years to 10 billion years after the Big Bang. They dug through their data, in search of the H-alpha line: a deep-red visible spectral line, which occurs when a hydrogen electron falls from its third to second lowest energy level.

In star forming regions, the surrounding gas is continually ionized by radiation from the newly formed stars. Once the gas is ionized, the nucleus and removed electron can recombine to form a new hydrogen atom with the electron typically in a higher energy state. This electron will then cascade back to the ground state, a process that produces H-alpha emission about half the time.

So the H-alpha line is an effective probe of star formation and the brightness of the H-alpha line (which is much easier to detect than the faint, almost invisible, continuum) is an effective probe of the star formation rate. From this single line, Attek and colleagues found that the rate at which stars are turning on in early dwarfs is surprisingly high.

“These galaxies are forming stars so quickly that they could actually double their entire mass of stars in only 150 million years — this sort of gain in stellar mass would take most normal galaxies 1-3 billion years,” said co-author Jean-Paul Kneib, also of EPFL.

The team doesn’t yet know why these small galaxies are producing such a vast number of stars. In general, bursts of star formation are thought to follow somewhat chaotic events like galactic mergers or the shock of a supernova. But by continuing to study these dwarf galaxies, astronomers hope to shed light on galactic evolution and help paint a consistent picture of events in the early Universe.

The paper has been published today in the Astrophysical Journal and may be viewed here. The latest Hubblecast (below) also covers this exciting result.

Subaru Telescope Reveals Orderly Massive Galaxy Evolution

FMOS spectra in the J-band (left panel) and H-band (right panel), each of which filters light so that only specific wavelengths can pass through. The horizontal axis refers to the wavelength direction while the vertical axis indicates individual spectra observed through each fiber. Small blue circles indicate the detection of emission lines (left: H? and [OIII]; right: H?, [NII]). The inset box shows the intensity of the emission lines for one galaxy. The vertical bands indicate the masked regions where bright sky (OH) emissions are prevented from entering science fibers placed on high-redshift galaxies. (Credit: FMOS-COSMOS)

Nobody likes a sloppy COSMOS (Cosmological Evolution Survey) and astronomers utilizing the Fiber-Multi-Object Spectrograph (FMOS) mounted on the Subaru Telescope have put order into chaos through their studies. The survey has found that some nine billion years ago galaxies were capable of producing new stars in a fashion as orderly as game of checkers. Despite their young cosmological age, the galaxies show signs containing high amounts of dust enriched by heavier elements – a mature state.

“These findings center on a major question: What was the universe like when it was maximally forming its stars?” says John Silverman, the principal investigator of the FMOS-COSMOS project at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU).

These “universal” questions are just what the COSMOS team seeks to answer. Their research goals are to enlighten the scales of cosmic time in relationship with the environment, formation and evolution of massive galactic structures. When studying individual galaxies, they may be able to tell if their rate of growth can be attributed to large-scale environments. Information of this type can clarify what factors the early Universe structure may have contributed to the current form of local galaxies. One of the data sets the team is focusing on is using the FMOS on the Subaru Telescope to chart out the distribution of more than a thousand galaxies which formed over nine billion years ago – a time when the Universe was hitting its star-formation peak.

“One key to generating fruitful results is collaboration between COSMOS researchers to maximize optimal use of FMOS.” Silverman continues, “In this project, researchers from Kavli IPMU in Japan and the Institute for Astronomy at the University of Hawaii (principal investigator: David Sanders) formed an effective collaboration to implement their goal.” The observations spanned 10 clear nights starting in March 2012.

Why choose spectroscopy? This advanced fiber optics technology speaks for itself, collecting light over an area of sky equal in size to that of the Moon. The FMOS focuses on the near-infrared, filtering out unwanted emissions caused by warm temperatures and can acquire spectra from 400 galaxies simultaneously with a wide field of coverage of 30 arc minutes at prime-focus. By employing such a wide field of view, astronomers can squeeze in a wide range of objects in their local environments. This enables researchers to maximize information on star-forming regions, cluster formation, and cosmology.

As David Sanders, the principal investigator of the FMOS-COSMOS project at IfA, puts it, “FMOS has clearly revolutionized our ability to study how galaxies form and evolve across cosmic time. It is currently the most powerful instrument we have to study the large numbers of objects needed to understand galaxies of all sizes, shapes and masses — from the largest ellipticals to the smallest dwarfs. We are extremely fortunate that the Kavli IPMU-IfA collaboration is giving us this unique opportunity to study the distant universe in such exquisite detail.”

FMOS will soon be famous by revealing its true potential. It has been collecting copious amounts of data in a high spectral resolution mode and at a very successful rate. So far it has accomplished nearly half of its goal – to examine over a thousand galaxies with redshifts to map the large-scale structure. The current survey consists of mapping an area of sky which spans a square degree in high-resolution mode and future plans for FMOS will involve enlarging the area. This expanded coverage will complement other instruments on alternative telescopes which have a wider spectral imaging system or a higher resolution which is limited to a smaller area. These combined findings may one day result in showing us some of the very first structures that eventually evolved into the massive galaxy clusters we see today!

Original Story Source: Kavli Institute for the Physics and Mathematics of the Universe News Release.

Taking Measure: A ‘New’ Most Distant Galaxy

Galaxy z8_GND_5296 (seen in the inset) is the earliest galaxy that astronomers have measured the distance to accurately. It formed approximately 700 million years after the Big Bang, and is forming stars at an incredibly rapid rate. [Credit: V. Tilvi (Texas A&M), S. Finkelstein (UT Austin), the CANDELS team, and HST/NASA]

“The farthest galaxy yet seen!” Haven’t we heard that one before? (See here and here, for example.) While it’s true that astronomers keep pushing farther back in time with better instruments, there are fundamental challenges both in observing and measuring the distances to the earliest galaxies in the cosmos.

That’s why this new observation of a galaxy that formed about 700 million years after the Big Bang is significant. While scores of galaxies have been identified that formed in that era, astronomers have only measured accurate distances for five of them. This galaxy marks the sixth, and it is the farthest of the bunch. Perhaps even more important than the distance measurement, researchers determined that this galaxy gave birth to new stars at more than 100 times the rate the Milky Way does today. That indicates early galaxies may have been more aggressive with star-formation than previously believed. Continue reading “Taking Measure: A ‘New’ Most Distant Galaxy”

Hubble Looks Back In Time To See Shape Of Galaxies 11 Billion Years Ago

This image shows "slices" of the Universe at different times throughout its history (present day, and at 4 and 11 billion years ago). Each slice goes further back in time, showing how galaxies of each type appear. The shape is that of the Hubble tuning fork diagram, which describes and separates galaxies according to their morphology. Credit: NASA, ESA, M. Kornmesser

What we’re gonna’ do here is go back. Way back into time. Back to when the only thing that existed was… galaxies? When astronomers employed the power of Hubble’s CANDELS survey to observe different galaxy types from the distant past, they expected to see a variety of spiral, elliptical, lenticular and peculiar structures, but what they didn’t expect was that things were a whole lot more “peculiar” a long time ago!

Known as the Hubble Sequence, astronomers use this classified system for listing galaxy sizes, shapes and colors. It also arranges galaxies according to their morphology and star-forming activity. Up to the present, the Hubble Sequence covered about 80% of the Universe’s history, but the latest information shows that the sequence was valid as much as 11 billion years ago! Out of what we currently know, there are two dominant galaxy types – spiral and elliptical – with the lenticular structure as a median. Of course, this is constrained to the regions of space which we can readily observe, but how true did the sequence hold back when the Universe theoretically began?

“This is a key question: when and over what timescale did the Hubble Sequence form?” says BoMee Lee of the University of Massachusetts, USA, lead author of a new paper exploring the sequence. “To do this you need to peer at distant galaxies and compare them to their closer relatives, to see if they too can be described in the same way.”

Using the Hubble Space Telescope, astronomers took on the sequence challenge to peer back 11 billion years in time to study galaxy structure. Up until now, researchers could confirm the sequence was valid as long ago as 8 billion years, but these new studies pushed CANDELS, the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, to the outer limits. It is simply the largest project ever, and soaked up 902 assigned orbits of observing time. Using the WFC3 and ACS cameras, the team examined structures that existed less than one billion years after the Big Bang. While earlier studies had aimed for lower-mass galaxies in this era, no study had really taken on serious observation of mature structures – ones similar to our own galaxy. Now the new CANDELS observations show us that all galaxies, regardless of size, fit into a totally different classification!

“This is the only comprehensive study to date of the visual appearance of the large, massive galaxies that existed so far back in time,” says co-author Arjen van der Wel of the Max Planck Institute for Astronomy in Heidelberg, Germany. “The galaxies look remarkably mature, which is not predicted by galaxy formation models to be the case that early on in the history of the Universe.”

Just what did this study see that’s so different? Just the power of two. Galaxies were either complex, with blue star forming regions and irregular structures, or they were like our nearby neighbors: massive red galaxies that exhibit no new star-formation. In the early Universe, galaxies like the Milky Way were uncommon. With so little to study, it was nearly impossible to get a large enough sample to sufficiently catalog their characteristics. Early research could only peer back in visible light, a format which emphasized star formation and revealed the red-shifted ultraviolet emission of the galaxies. This information was inconclusive because galaxy structure appeared disrupted and unlike the formations we see near to us. Through the use of infra-red, astronomers could observe the now red-shifted massive galaxies in their visible rest frame. Thanks to CANDELS lighting the way, astronomers were able to thoroughly sample a significantly larger amount of mature galaxies in detail.

“The huge CANDELS dataset was a great resource for us to use in order to consistently study ancient galaxies in the early Universe,” concludes Lee. “And the resolution and sensitivity of Hubble’s WFC3 is second to none in the infrared wavelengths needed to carry out this study. The Hubble Sequence underpins a lot of what we know about how galaxies form and evolve — finding it to be in place this far back is a significant discovery.”

Original Story Source: ” Hubble Explores the Origins of Modern Galaxies” – Hubble News Release.

The Great Galactic Turn-Off

This image shows 20 of the quenched galaxies — galaxies that are no longer forming stars — seen in the Hubble COSMOS observations. Each galaxy is identified by a crosshair at the centre of each frame. Quenched galaxies in the distant Universe are much smaller than those seen nearby. It was thought that these small galaxies merged with other smaller, gas-free galaxies to grow bigger, but it turns out that larger galaxies were "switching off" at later times and adding their numbers to those of their smaller and older siblings, giving the mistaken impression of individual galaxy growth over time. Credit: NASA, ESA, M. Carollo (ETH Zurich)

Are you ready for a new galactic puzzle? Then let’s start with some clues. It has been long assumed that some galaxies reach a point in their evolution when star formation stops. In the distant past, these saturated galaxies appeared smaller than those formed more recently. This is what baffles astronomers. Why do some galaxies continue to grow if they are no longer forming stars? Thanks to some very astute Hubble Space Telescope observations, a team of astronomers has found what appears to be a rather simple explanation. Which came first? The chicken or the egg?

Until now, these diminutive, turned-off galaxies were theorized to continue to grow into the more massive, saturated galaxies observed closer to us. Because they no longer have active star-forming regions, it was assumed they gained their extra mass by combining with other smaller galaxies – ones five to ten times less in overall size. However, for this theory to be plausible, it would take a host of small galaxies to be present for the saturated population to consume… and it’s just not happening. Because we simply did not have the data available about such a large number of galaxies, it was impossible to count and identify potential candidates, but the Hubble COSMOS survey has provided an eight billion year look at the cosmic history of turned-off galaxies.

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“The apparent puffing up of quenched galaxies has been one of the biggest puzzles about galaxy evolution for many years,” says Marcella Carollo of ETH Zurich, Switzerland, lead author on a new paper exploring these galaxies. “No single collection of images has been large enough to enable us to study very large numbers of galaxies in exactly the same way — until Hubble’s COSMOS,” adds co-author Nick Scoville of Caltech, USA.

According to the news release, the team utilized a large set of COSMOS images – the product of close to a 1,000 hours of observations and consisting of 575 over-lapped images taken with the Advanced Camera for Surveys (ACS) . Needless to say, it was one of the most ambitious projects ever undertaken by Hubble. The HST data was combined with additional observations from Canada-France-Hawaii Telescope and the Subaru Telescope to look back to when the Universe was about half its present age. This huge data set covered an area of sky almost nine times the size of the full Moon! The saturated – or “quenched” – galaxies present at that age were small and compact… and apparently remained in that state. Instead of getting larger as they evolved, they kept their small size – apparently the same size they were when star-formation ceased. Yet, these galaxy types appear to be gaining in girth as time passes. What gives?

“We found that a large number of the bigger galaxies instead switch off at later times, joining their smaller quenched siblings and giving the mistaken impression of individual galaxy growth over time,” says co-author Simon Lilly, also of ETH Zurich. “It’s like saying that the increase in the average apartment size in a city is not due to the addition of new rooms to old buildings, but rather to the construction of new, larger apartments,” adds co-author Alvio Renzini of INAF Padua Observatory, Italy.

If eight billion years teaches us anything, it teaches us that we don’t know everything…. and sometimes the most simple of answers could be the correct one. We knew that actively star-forming galaxies were far less massive in the early Universe and that explains why they were smaller when star-formation turned off.

“COSMOS provided us with simply the best set of observations for this sort of work — it lets us study very large numbers of galaxies in exactly the same way, which hasn’t been possible before,” adds co-author Peter Capak, also of Caltech. “Our study offers a surprisingly simple and obvious explanation to this puzzle. Whenever we see simplicity in nature amidst apparent complexity, it’s very satisfying,” concludes Carollo.

Original Story Source: ESA/Hubble News Release.

Fast Working ALMA Resolves Star-Forming Galaxies

A team of astronomers has used ALMA (the Atacama Large Millimeter/submillimeter Array) to pinpoint the locations of over 100 of the most fertile star-forming galaxies in the early Universe. Credit:: ALMA (ESO/NAOJ/NRAO), J. Hodge et al., A. Weiss et al., NASA Spitzer Science Center

In a scenario where millions of years are considered a short period of time, hours are barely a blink of an eye. While it might take ten years or more to observe a group of galaxies with a modicum of detail for telescopes around the world, the Atcama Large Millimeter/submillimeter Array (ALMA) telescope was able to do the job at amazing speed. In just a matter of hours, a team of astronomers using this super-powerful telescope homed in on the location of over a hundred star-forming galaxies in the early Universe.

Once upon a time, huge amounts of star birth occurred in early galaxies which were rich in cosmic dust. Studying these galaxies is imperative to our understanding of galactic formation and evolution – but it has proved difficult in visible light because the very dust which supports star formation also cloaks the galaxies in which they are formed. However, thanks to telescopes like ALMA, we’re able to identify and observe these galaxies by focusing on longer wavelengths. Light that comes in around one millimetre is the perfect playground for such study.

“Astronomers have waited for data like this for over a decade. ALMA is so powerful that it has revolutionised the way that we can observe these galaxies, even though the telescope was not fully completed at the time of the observations,” said Jacqueline Hodge (Max-Planck-Institut für Astronomie, Germany), lead author of the paper presenting the ALMA observations.

Just how do we know where these galaxies are located? Through the use of the ESO-operated Atacama Pathfinder Experiment telescope (APEX), astronomers were able to map these dust obscured targets to a certain degree. APEX focused its capabilities on an area of sky about the size of the full Moon in the constellation of Fornax. The study – Chandra Deep Field South – has been taken on by a variety of telescopes located both here on Earth and in space. Here is where APEX has been credited with locating 126 dusty galaxies. However, these images aren’t all they could be. Star forming areas appeared as blobs and sometimes could over-ride better images made at other wavelengths. Through the use of ALMA, these observations have been augmented, furthering the resolution in the millimetre/submillimetre portion of the spectrum and assisting astronomers in knowing precisely which galaxies are forming stars.

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This video sequence starts with a broad view of the sky, including the famous constellation of Orion (The Hunter). We gradually close in on an unremarkable patch of sky called the Chandra Deep Field South that has been studied by many telescopes on the ground and in space. Credit: ALMA (ESO/NAOJ/NRAO), APEX (MPIfR/ESO/OSO), J. Hodge et al., A. Weiss et al., NASA Spitzer Science Center, Digitized Sky Survey 2, and A. Fujii. Music: Movetwo

As all backyard astronomers know, the larger the aperture – the better the resolution. To improve their observations of the early Universe, astronomers needed a bigger telescope. APEX consists of a twelve meter diameter dish-shaped antenna, but ALMA consists of many dishes spread over long distances. The signals from all of its parts are then combined and the result is the same as if it were a giant telescope which measured the same size as the entire array. A super dish!

With the assistance of ALMA, the astronomers then took on the galaxies from the APEX map. Even though the ALMA array is still under construction and using less than a quarter of its capabilities, the team was able to complete this beginning phase of scientific observations. Speedy ALMA was up to the task. At only two minutes per galaxy, this “Super Scope” was able to resolve each one within a minuscule area two hundred times smaller than the original APEX blobs… and with 300% more sensitivity! With a track record like that, ALMA was able to double the number of observations in a matter of hours. Now the researchers were able to clearly see which galaxies contained active star forming regions and distinguish cases where multiple star-forming galaxies had melded to appear as one in earlier studies.

“We previously thought the brightest of these galaxies were forming stars a thousand times more vigorously than our own galaxy, the Milky Way, putting them at risk of blowing themselves apart. The ALMA images revealed multiple, smaller galaxies forming stars at somewhat more reasonable rates,” said Alexander Karim (Durham University, United Kingdom), a member of the team and lead author of a companion paper on this work.

Apparently ALMA is going to be a huge success. These new observations have helped to confidently document dusty star-forming galaxies from the early Universe and help to create a more detailed catalog than ever before. These new findings will assist future astronomical observations by giving researchers a reliable base on these galaxies’ properties at different wavelengths. No longer will astronomers have to “guess” at which galaxies may have melded together in images… ALMA has made it clear. However, don’t rule out the use of other venues such as APEX. The combination of both play a powerful part in observing the early Universe.

“APEX can cover a wide area of the sky faster than ALMA, and so it’s ideal for discovering these galaxies. Once we know where to look, we can use ALMA to locate them exactly,” concluded Ian Smail (Durham University, United Kingdom), co-author of the new paper.

Original Story Source: ESO Science News Release.

Monster Black Holes Lurk at the Edge of Time

The reddish object in this infrared image is ULASJ1234+0907, located about 11 billion light-years from Earth. The red color comes from vast amounts of dust, which absorbs bluer light, and obscures the supermassive black hole from view in visible wavelengths. Credit: image created using data from UKIDSS and the Wide-field Infrared Survey Explorer (WISE) observatory.

As if staring toward the edge of the Universe weren’t fascinating enough, scientists at the University of Cambridge say they see enormous, rapidly growing supermassive black holes barely detectable near the edge of time.

Thick dust shrouds the monster black holes but they emit vast amounts of radiation through violent interactions and collisions with their host galaxies making them visible in the infrared part of the electromagnetic spectrum. The team published their results in the journal Monthly Notices of the Royal Astronomical Society.

The most remote object in the study lies at a whopping 11 billion light-years from Earth. Ancient light from the supermassive black hole, named ULASJ1234+0907 and located toward the constellation of Virgo, the Maiden, has traveled (at almost 10 trillion kilometers, or 6 million million miles, per year) across the cosmos for nearly the estimated age of the Universe. The monster black hole is more than 10 billion times the mass of our Sun and 10,000 times more massive than the black hole embedded in the Milky Way Galaxy; making it one of the most massive black holes ever seen. And it’s not alone. Researchers say that there may be as many as 400 giants black holes in the tiny sliver of the Universe that we can observe.

“These results could have a significant impact on studies of supermassive black holes” said Dr Manda Banerji, lead author of the paper, in a press release. “Most black holes of this kind are seen through the matter they drag in. As the neighbouring material spirals in towards the black holes, it heats up. Astronomers are able to see this radiation and observe these systems.”

The team from Cambridge used infrared surveys being carried out on the UK Infrared Telescope (UKIRT) to peer through the dust and locate the giant black holes for the first time.

“These results are particularly exciting because they show that our new infrared surveys are finding super massive black holes that are invisible in optical surveys,” says Richard McMahon, co-author of the study. “These new quasars are important because we may be catching them as they are being fed through collisions with other galaxies. Observations with the new Atacama Large Millimeter Array (ALMA) telescope in Chile will allow us to directly test this picture by detecting the microwave frequency radiation emitted by the vast amounts of gas in the colliding galaxies.”

Huge black holes are known to reside at the centers of all galaxies. Astronomers predict the most massive of these cosmic phenomena grow through violent collisions with other galaxies. Galactic interactions trigger star formation which provides more fuel for black holes to devour. And it’s during this process that thick layers of dust hide the munching black holes.

“Although these black holes have been studied for some time,” says Banergi, “the new results indicate that some of the most massive ones may have so far been hidden from our view. The newly discovered black holes, devouring the equivalent of several hundred Suns every year, will shed light on the physical processes governing the growth of all supermassive black holes.”

Astronomers compare the extreme case of ULASJ1234+0907 with the relatively nearby and well-studied Markarian 231. Markarian 231, found just 600 million light-years away, appears to have recently undergone a violent collision with another galaxy producing an example of a dusty, growing black hole in the local Universe. By contrast, the more extreme example of ULASJ1234+0907, shows scientists that conditions in the early Universe were more turbulent and inhospitable than today.

Source: Royal Astronomical Society

Image Credit: Markarian 231, an example of a galaxy with a dusty rapidly growing supermassive black hole located 600 million light years from Earth. The bright source at the center of the galaxy marks the black hole while rings of gas and dust can be seen around it as well as “tidal tails” left over from a recent impact with another galaxy. Courtesy of NASA/ESA Hubble Space Telescope.

Oldest Spiral Galaxy in the Universe Discovered

An artist’s rendering of galaxy BX442 and its companion dwarf galaxy (upper left)

Caption: An artist’s rendering of galaxy BX442 and its companion dwarf galaxy (upper left). Credit: Dunlap Institute for Astronomy & Astrophysics/Joe Bergeron

Ancient starlight traveling for 10.7 billion years has brought a surprise – evidence of a spiral galaxy long before other spiral galaxies are known to have formed.

“As you go back in time to the early universe, galaxies look really strange, clumpy and irregular, not symmetric,” said Alice Shapley, a UCLA associate professor of physics and astronomy, and co-author of a study reported in today’s journal Nature. “The vast majority of old galaxies look like train wrecks. Our first thought was, why is this one so different, and so beautiful?”

Galaxies today come in a variety of unique shapes and sizes. Some, like our Milky Way Galaxy, are rotating disks of stars and gas called spiral galaxies. Other galaxies, called elliptical galaxies, resemble giant orbs of older reddish stars moving in random directions. Then there are a host of smaller irregular shaped galaxies bound together by gravity but lacking in any visible structure. A great, diverse population of these types of irregular galaxies dominated the early Universe, says Shapely.

Light from this incredibly distant spiral galaxy, traveling at nearly six trillion miles per year, took 10.7 billion years to reach Earth; just 3 billion years after the Universe was created in an event called the Big Bang.

According to a press release from UCLA, astronomers used the sharp eyes of the Hubble Space Telescope to spy on 300 very distant galaxies in the early Universe. The scientists originally thought their galaxy, one of the most massive in their survey going by the unglamorous name of BX442, was an illusion, perhaps two galaxies superimposed on each other.

“The fact that this galaxy exists is astounding,” said David Law, lead author of the study and Dunlap Institute postdoctoral fellow at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics. “Current wisdom holds that such ‘grand-design’ spiral galaxies simply didn’t exist at such an early time in the history of the universe.” A ‘grand design’ galaxy has prominent, well-formed spiral arms.

To understand their image further, astronomers used a unique, state-of-the-art instrument called the OSIRIS spectrograph at the W.M. Keck Observatory atop Hawaii’s dormant Mauna Kea volcano. The instrument, built by UCLA professor James Larkin, allowed them to study light from about 3,600 locations in and around BX442. This spectra gave them the clues they needed to show they were indeed looking at a single, rotating spiral galaxy.

While spiral galaxies are abundant throughout the current cosmos, that wasn’t always the case. Spiral galaxies in the early Universe were rare because of frequent interactions. “BX442 looks like a nearby galaxy, but in the early universe, galaxies were colliding together much more frequently,” says Shapely. “Gas was raining in from the intergalactic medium and feeding stars that were being formed at a much more rapid rate than they are today; black holes grew at a much more rapid rate as well. The universe today is boring compared to this early time.”

Shapely and Law think the gravitational tug-of-war between a dwarf galaxy companion and BX442 may be responsible for its futuristic look. The companion appears as just a small blob in their image. Computer simulations conducted by Charlotte Christensen, a postdoctoral student at the University of Arizona and co-author of the paper, lends evidence to this idea. Eventually, BX442 and the smaller galaxy likely will merge.

Shapley said BX442 represents a link between early galaxies that are much more turbulent and the rotating spiral galaxies that we see around us. “Indeed, this galaxy may highlight the importance of merger interactions at any cosmic epoch in creating grand design spiral structure,” she said.

Studying BX442 is likely to help astronomers understand how spiral galaxies like the Milky Way form, she added.

Caption 2: HST/Keck false color composite image of galaxy BX442. Credit: David Law/Dunlap Institute for Astronomy & Astrophysics

Early Black Holes were Grazers Rather than Glutonous Eaters

Faint quasars powered by black holes. Image credit NASA/ESA/Yale

Black holes powering distant quasars in the early Universe grazed on patches of gas or passing galaxies rather than glutting themselves in dramatic collisions according to new observations from NASA’s Spitzer and Hubble space telescopes.

A black hole doesn’t need much gas to satisfy its hunger and turn into a quasar, says study leader Kevin Schawinski of Yale “There’s more than enough gas within a few light-years from the center of our Milky Way to turn it into a quasar,” Schawinski explained. “It just doesn’t happen. But it could happen if one of those small clouds of gas ran into the black hole. Random motions and stirrings inside the galaxy would channel gas into the black hole. Ten billion years ago, those random motions were more common and there was more gas to go around. Small galaxies also were more abundant and were swallowed up by larger galaxies.”

Quasars are distant and brilliant galactic powerhouses. These far-off objects are powered by black holes that glut themselves on captured material; this in turn heats the matter to millions of degrees making it super luminous. The brightest quasars reside in galaxies pushed and pulled by mergers and interactions with other galaxies leaving a lot of material to be gobbled up by the super-massive black holes residing in the galactic cores.

Schawinski and his team studied 30 quasars with NASA’s orbiting telescopes Hubble and Spitzer. These quasars, glowing extremely bright in the infrared images (a telltale sign that resident black holes are actively scooping up gas and dust into their gravitational whirlpool) formed during a time of peak black-hole growth between eight and twelve billion years ago. They found 26 of the host galaxies, all about the size of our own Milky Way Galaxy, showed no signs of collisions, such as smashed arms, distorted shapes or long tidal tails. Only one galaxy in the study showed evidence of an interaction. This finding supports evidence that the creation of the most massive black holes in the early Universe was fueled not by dramatic bursts of major mergers but by smaller, long-term events.

“Quasars that are products of galaxy collisions are very bright,” Schawinski said. “The objects we looked at in this study are the more typical quasars. They’re a lot less luminous. The brilliant quasars born of galaxy mergers get all the attention because they are so bright and their host galaxies are so messed up. But the typical bread-and-butter quasars are actually where most of the black-hole growth is happening. They are the norm, and they don’t need the drama of a collision to shine.

“I think it’s a combination of processes, such as random stirring of gas, supernovae blasts, swallowing of small bodies, and streams of gas and stars feeding material into the nucleus,” Schawinski said.

Unfortunately, the process powering the quasars and their black holes lies below the detection of Hubble making them prime targets for the upcoming James Webb Space Telescope, a large infrared orbiting observatory scheduled for launch in 2018.

You can learn more about the images here.

Image caption: These galaxies have so much dust enshrouding them that the brilliant light from their quasars cannot be seen in these images from the NASA/ESA Hubble Space Telescope.

Hubble Captures Giant Lensed Galaxy Arc

Thanks to the presence of a natural "zoom lens" in space, this is a close-up look at the brightest distant "magnified" galaxy in the universe known to date. Credit: NASA, ESA, J. Rigby (NASA Goddard Space Flight Center), K. Sharon (Kavli Institute for Cosmological Physics, University of Chicago), and M. Gladders and E. Wuyts (University of Chicago)


Less than a year ago, the Hubble Space Telescope’s Wide Field Camera 3 captured an amazing image – a giant lensed galaxy arc. Gravitational lensing produces a natural “zoom” to observations and this is a look at one of the brightest distant galaxies so far known. Located some 10 billion light years away, the galaxy has been magnified as a nearly 90-degree arc of light against the galaxy cluster RCS2 032727-132623 – which is only half the distance. In this unusual case, the background galaxy is over three times brighter than typically lensed galaxies… and a unique look back in time as to what a powerful star-forming galaxy looked like when the Universe was only about one third its present age.

A team of astronomers led by Jane Rigby of NASA’s Goddard Space Flight Center in Greenbelt, Maryland are the parties responsible for this incredible look back into time. It is one of the most detailed looks at an incredibly distant object to date and their results have been accepted for publication in The Astrophysical Journal, in a paper led by Keren Sharon of the Kavli Institute for Cosmological Physics at the University of Chicago. Professor Michael Gladders and graduate student Eva Wuyts of the University of Chicago were also key team members.

“The presence of the lens helps show how galaxies evolved from 10 billion years ago to today. While nearby galaxies are fully mature and are at the tail end of their star-formation histories, distant galaxies tell us about the universe’s formative years. The light from those early events is just now arriving at Earth.” says the team. “Very distant galaxies are not only faint but also appear small on the sky. Astronomers would like to see how star formation progressed deep within these galaxies. Such details would be beyond the reach of Hubble’s vision were it not for the magnification made possible by gravity in the intervening lens region.”

This graphic shows a reconstruction (at lower left) of the brightest galaxy whose image has been distorted by the gravity of a distant galaxy cluster. The small rectangle in the center shows the location of the background galaxy on the sky if the intervening galaxy cluster were not there. The rounded outlines show distinct, distorted images of the background galaxy resulting from lensing by the mass in the cluster. The image at lower left is a reconstruction of what the lensed galaxy would look like in the absence of the cluster, based on a model of the cluster's mass distribution derived from studying the distorted galaxy images. Illustration Credit: NASA, ESA, and Z. Levay (STScI) Science Credit: NASA, ESA, J. Rigby (NASA Goddard Space Flight Center), K. Sharon (Kavli Institute for Cosmological Physics, University of Chicago), and M. Gladders and E. Wuyts (University of Chicago)

But the Hubble isn’t the only eye on the sky examining this phenomenon. A little over 10 years ago a team of astronomers using the Very Large Telescope in Chile also measured and examined the arc and reported the distant galaxy seems to be more than three times brighter than those previously discovered. However, there’s more to the picture than meets the eye. Original images show the magnified galaxy as hugely distorted and it shows itself more than once in the foreground lensing cluster. The challenge was to create a image that was “true to life” and thanks to Hubble’s resolution capabilities, the team was able to remove the distortions from the equation. In this image they found several incredibly bright star-forming regions and through the use of spectroscopy, they hope to better understand them.

Original Story Source: Hubble News Release.