Tag Archives: quasar

This artist’s impression shows how the distant quasar P172+18 and its radio jets may have looked. To date (early 2021), this is the most distant quasar with radio jets ever found and it was studied with the help of ESO’s Very Large Telescope. It is so distant that light from it has travelled for about 13 billion years to reach us: we see it as it was when the Universe was only about 780 million years old. (ESO)

Astronomers have discovered the most distant radio signal ever

With assistance from the ESO’s Very Large Telescope (VLT), astronomers have discovered the most distant radio emission ever recorded. The source is a quasar so distant that its light has been travelling 13 billion years to reach us. That means that it existed when the Universe was just 780 or so million years old.

This artist’s impression shows how the distant quasar P172+18 and its radio jets may have looked. To date (early 2021), this is the most distant quasar with radio jets ever found and it was studied with the help of ESO’s Very Large Telescope. It is so distant that light from it has travelled for about 13 billion years to reach us: we see it as it was when the Universe was only about 780 million years old. (ESO)
This artist’s impression shows how the distant quasar P172+18 and its radio jets may have looked. To date (early 2021), this is the most distant quasar with radio jets ever found and it was studied with the help of ESO’s Very Large Telescope. It is so distant that light from it has travelled for about 13 billion years to reach us: we see it as it was when the Universe was only about 780 million years old. (ESO)

The object–named P172+18–is what astronomers term a ‘radio loud’ quasar, shining powerfully in the radio-frequency region of the electromagnetic spectrum, extremely bright due to the powerful jets emitted from its axis. Radio loud quasars are fairly rare with only 10% of discovered quasars fitting this description.

This makes the team’s finding even more extraordinary as even though more distant quasars have been found, it marks the first time that researchers have been able to identify the tell-tale signs of powerful radio-bright jets at such incredible cosmic distances.

Excitingly, the team at the centre of this finding believe that this is just the tip of the iceberg with regards to radio-loud quasars, with many more yet to be discovered. Possibly even some at much greater distances.

The team’s discovery is discussed in a paper published in the latest edition of The Astrophysical Journal.

Quasars: Powered By Black Holes

Quasars are objects that lie at the centre of galaxies, powered by supermassive black hole ‘engines.’ The black hole at the heart of P172+18 is a doozy. The team estimate it is around 300 million times the mass of the Sun. As impressive as that is, perhaps more staggering is the rate at which this supermassive black hole is consuming gas and dust.

VLBA image of another distant radio bright quasar P352–15. the team believe these objects could be common in the Universe and at extreme distances [Momjian, et al.; B. Saxton (NRAO/AUI/NSF)]

“The black hole is eating up matter very rapidly, growing in mass at one of the highest rates ever observed,” says Chiara Mazzucchelli, co-leader of the project and an astronomer based at ESO, Chile. “I find it very exciting to discover ‘new’ black holes for the first time, and to provide one more building block to understand the primordial Universe, where we come from, and ultimately ourselves.”

The team believes that the rapid rate of gas consumption displayed by the supermassive black hole and its burgeoning growth are both intrinsically linked to the emission of the radio bright jets they detected. The jets could be disturbing gas in an accretion disc around the black hole, causing it to fall into the central black hole at an accelerated rate.

If this proves to be the case, the study of radio-loud quasars could be of vital importance in the future investigation of the growth of black holes in the infant Universe. There is currently some confusion as to how supermassive black holes could have grown to tremendous sizes over a relatively short-period in cosmic terms, thus a mechanism that accounts for rapid growth is a boon to cosmologists fearing that models of cosmic evolution could need fundamental revision.

Very Loud and Very Far Away

P172+18 was first spotted as a radio source in data gathered by t the Magellan Telescope at Las Campanas Observatory in Chile. Mazzucchelli and team co-leader Eduardo Bañados of the Max Planck Institute for Astronomy, Germany, then assessed the data and quickly concluded that the radio source represented jets produced by a distant radio-loud quasar.

“As soon as we got the data, we inspected it by eye, and we knew immediately that we had discovered the most distant radio-loud quasar known so far,” says Bañados.

This visible-light, wide-field image of the region around the distant quasar P172+18 was created from images in the Digitized Sky Survey 2. The object itself lies very close to the centre and is not visible in this picture, but many other, much closer, galaxies are seen in this wide-field view. (ESO/ Digitized Sky Survey 2/ Davide De Martin)

Because P172+18 was only observed for a brief period, it was necessary for the duo to follow up the observations with other telescopes. They were able to do this with the use of the X-Shooter instrument associated with the VLT, based in the Atacama Desert, Chile, as well as the National Radio Astronomy Observatory’s Very Large Array (VLA) in New Mexico, and the Keck Telescope located near the summit of Mauna Kea, Hawaii.

These follow-up observations allowed the team to ascertain a wealth of details about the quasar and the supermassive black hole powering it, including its mass and the rapid rate at which it is consuming gas and surrounding matter.

P172+18 may currently hold the record for most distant radio-loud quasar, but it is not a distinction that Mazzucchelli and Bañados think it will hang on to for long. The duo believes that many more radio-loud quasars are lurking in the Universe waiting to be discovered and that undoubtedly, some of these will exist at greater distances than 13 billion light-years.

Whilst these may be a challenge to spot currently, the ESO’s forthcoming Extremely Large Telescope (ELT), currently under construction in Northern Chile, should be powerful enough to handle such observations.

“This discovery makes me optimistic and I believe — and hope — that the distance record will be broken soon,” concludes  Bañados.

Fastest-growing black hole in the universe eats the equivalent of one sun per day

This artist’s impression shows how ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun, may have looked. This quasar is the most distant yet found and is seen as it was just 770 million years after the Big Bang. This object is by far the brightest object yet discovered in the early Universe. Credit: ESO/M. Kornmesser

Astronomers have come across a monstrously large black hole with a gargantuan appetite. Each passing day, the insatiable void known as J2157 consumes gas and dust equivalent in mass to the sun, making it the fastest-growing black hole in the universe.

The sheer scale of J2157 is almost unfathomable, but we can try pinning some numbers on it nevertheless.

According to Christopher Onken, an astronomer at the Australian National University who was part of the team that originally discovered the object in 2019, J2167 is 8,000 times more massive than the supermassive black hole found at the heart of the Milky Way. That’s equivalent to 34 billion times the mass of the Sun.

In order for Sagittarius A*, the Milky Way’s supermassive black hole, to reach a similar size, it would have had to gobble two-thirds of all the stars in the galaxy.

For their new study, astronomers turned to ESO’s Very Large Telescope in Chile to get a more accurate assessment of the black hole‘s mass. The researchers already knew they were dealing with a black hole of epic proportions, but the final results surprised everyone.

“We knew we were onto a very massive black hole when we realized its fast growth rate,” said team member Dr. Fuyan Bian, a staff astronomer at ESO.

“How much black holes can swallow depends on how much mass they already have.  So, for this one to be devouring matter at such a high rate, we thought it could become a new record holder. And now we know.” 

Although black holes can’t be imaged directly because they don’t let light escape, J2157 is actually classed as a quasar, or “quasi-stellar radio source” — extremely bright objects powered by black holes at least a billion times as massive as our sun.

The bright signal of the quasar is formed by particles of dust and gas accreting around the edge of the supermassive black hole that are accelerated away at almost the speed of light. Practically, the black hole acts like an extremely powerful natural particle accelerator.

Luckily for us, the black hole is located many billions of light-years away. But this also means that astronomers are measuring J2157’s gravitational influence as it appeared in the distant past when the universe was still very young.

“We’re seeing it at a time when the universe was only 1.2 billion years old, less than 10 percent of its current age,” Dr Onken said. 

“It’s the biggest black hole that’s been weighed in this early period of the Universe.” 

Since then, J2157 likely grew even bigger, perhaps merging with several other black holes across the eons.

“With such an enormous black hole, we’re also excited to see what we can learn about the galaxy in which it’s growing,” Dr Onken said. 

“Is this galaxy one of the behemoths of the early Universe, or did the black hole just swallow up an extraordinary amount of its surroundings? We’ll have to keep digging to figure that out.” 

The findings appeared in the Monthly Notices of the Royal Astronomical Society.

Dark matter is colder than we thought — and we know this thanks to Einsteins crosses

Clumps of dark matter can be surprisingly small — and cold.

Researchers were able to indirectly detect dark matter using these distorted images of a background quasar and its host galaxy.

Astronomers love to give weird names to things, but “dark matter” is pretty self-explanatory. It’s matter, or we think it is, because it exerts a gravitational pull. It’s also dark, cause we can’t see it (although we observe its effect) — and that’s pretty much all we know about it.

Dark matter is estimated to account for approximately 85% of the matter in the universe, and yet we don’t really know what it is. But a new study might help us in that regard.

As weird as it may sound, dark matter seems to “clump together”. Turns out, these clumps can be much smaller than we thought. This confirms a fundamental prediction about dark matter, and can help researchers make an important breakthrough in understanding this enigmatic phenomenon.

A dark hunt

Dark matter is invisible to all our instruments. It doesn’t emit light or any detectable radiation. We never imaged it in any direct way. So when studying dark matter, astrophysicists look for its effects.

The most prevalent of these effects is its gravitational effect. According to such observations, dark matters appears to be the gravitational “glue” holding galaxies together.

We don’t know what kind of particles dark matter would be made of, but it almost certainly wouldn’t be the electrons, protons, and neutrons we’re familiar with. A popular theory holds that whatever particles it may be made of, these particles wouldn’t move very fast. This would help explain why dark matter tends to clump together, and while the dark matter concentrations across the universe can vary so much.

If this were the case, this would make for “cold” dark matter. A competing theory supports the idea of “hot” dark matter, where particles are moving at relativistic speeds (close to the speed of light).

Clumps of dark matter can help solve this dilemma. “Hot” dark matter wouldn’t allow the formation of small clumps, they simply move too fast to allow small chunks to form. So if we could detect small clumps, this would lend support to the “cold” dark matter hypothesis.

But remember how we said that dark matter can’t be imaged? Yeah, that’s still a problem.

Gravitational lensing

So instead, researchers took to an old tool: gravitational lensing. But they gave it a new twist.

Gravitational lensing, as the name implies, is the technique of using gravitational attraction as a lens. Everything has a gravitational pull, but objects that are really massive can distort even light itself. While this is often a very subtle distortion, it’s still detectable.

Think of it this way: if we’re looking at a distant, bright galaxy through a telescope, and another massive object is interposed between our telescope and the galaxy, its gravitation can act as a lens, bending the light. This is what was done in this study.

Image credits: NASA, ESA, and D. Player/STScI.

As you might have guessed, this requires a very particular alignment — which means that gravitational lenses must be found — and they may not exist in the directions we want them.

But sometimes, ever so rarely, the objects involved are lined up in such a way that four distorted images are produced around the lensing object. This is called an Einstein cross. This is where things get really interesting.

You might be wondering what any of this has to do with dark matter. Well, the gravitational influence of dark matter clumps should be observable — even that of smaller clumps.

The team used the Hubble Space Telescope to study eight Einstein cross quasars — extremely luminous galactic cores powered by supermassive black holes. These quasars were gravitationally lensed by massive foreground galaxies.

“Imagine that each one of these eight galaxies is a giant magnifying glass,” said UCLA astrophysicist Daniel Gilman, one of the study authors.

“Small dark matter clumps act as small cracks on the magnifying glass, altering the brightness and position of the four quasar images compared to what you would expect to see if the glass were smooth.”

The eight quasars and galaxies were aligned so precisely that the warping effect produced four distorted images of each quasar, almost like looking at a carnival mirror. Such alignments are very rare and were fortunate for this study.

The presence of the dark matter clumps altered the apparent brightness and position of each distorted quasar image. The researchers measured how the light was warped by the lens, and then looked at the brightness and position of each of the images, comparing these against predictions of how the Einstein crosses would look without dark matter. These comparisons allowed them to calculate the mass of the dark matter clumps causing the distortion.

According to the results, small dark matter clumps could exist — and these observations support the existence of colder dark matter.

“Dark matter is colder than we knew at smaller scales,” said Anna Nierenberg of NASA’s Jet Propulsion Laboratory in Pasadena, California, leader of the Hubble survey. “Astronomers have carried out other observational tests of dark matter theories before, but ours provides the strongest evidence yet for the presence of small clumps of cold dark matter. By combining the latest theoretical predictions, statistical tools and new Hubble observations, we now have a much more robust result than was previously possible.”

This does not rule out the possibility of hotter dark matter, but lends more weight to the colder theory. To make matters even more complex, there is also a mixed dark matter model that includes both types. However, this is almost certainly not the last study of this type.

Astronomers will be able to conduct follow-up studies of dark matter using future NASA space telescopes such as the James Webb Space Telescope and the Wide Field Infrared Survey Telescope, both infrared observatories.

It’s remarkable that after decades of service, the Hubble telescope still provides extremely useful information, allowing us to understand aspects of the surrounding universe.

As for dark matter, we won’t unravel its secrets today or tomorrow. We’re still taking baby steps, but one at a time, we’re getting closer to understanding what it really is — and maybe then, it won’t be dark matter anymore.

The team will present its results at the 235th meeting of the American Astronomical Society in Honolulu.

Scientists discover 83 Quasars from the early universe

Turns out black holes at the dawn of the universe weren’t that uncommon after all.

Artistic depiction of quasars. Image credits: NASA / JPL.

Researchers from Princeton, Japan, and Taiwan have found 83 quasars powered by supermassive black holes that were formed when the universe was less than 0.7 billion years old — less than 5% of its current age. This increases the number of black holes known at that epoch considerably and reveals how common they really were early in the history of our universe.

“The quasars we discovered will be an interesting subject for further follow-up observations with current and future facilities,” said Yoshiki Matsuoka of Ehime University in Japan, who led the study. “We will also learn about the formation and early evolution of supermassive black holes, by comparing the measured number density and luminosity distribution with predictions from theoretical models.”

The Subaru Telescope of the National Astronomical Observatory of Japan in Hawaii spotted the quasars up to 13.05 billion light-years away with an average spacing between each at a billion light-years. Three telescopes were involved in the project – the Subaru, the Gemini South Telescope in Chile, and the Gran Telescopio Canarias on La Palma in the Canary Islands, Spain. The discovery appeared in a series of five papers published in The Astrophysical Journal and the Publications of the Astronomical Observatory of Japan.

Black holes are regions of spacetime which have an extreme amount of matter packed into a tiny area — think of a star 10 times more massive than the sun pressed into a sphere the size of New York City. This results in a gravitational field so strong that not even light or presidential tweets can escape (although it has been hypothesized that something called “Hawking radiation” can).

The recently discovered black holes can be millions or even billions of times more massive than the sun. A supermassive black hole becomes visible when gas accretes into it. This causes it to shine as a “quasar.” Researchers have estimated the black holes to be around 13 billion years old. By comparison, the Big Bang is said to have happened 13.3 billion years ago, with Earth being a spritely 4.5 billion years in age.

Researchers on the project utilized data taken with a cutting-edge instrument called a “Hyper Suprime-Cam” (HSC), mounted on the Subaru Telescope. HSC has a gigantic field-of-view — 1.77 degrees across, or seven times the area of the full moon. The HSC team selected quasar candidates using the data to carry out an intensive observational campaign to obtain the spectra of the candidates using the three telescopes. Using 17 already-known quasars in the survey region, the researchers were able to find roughly one supermassive black hole per cubic giga-light-year.

“It is remarkable that such massive dense objects were able to form so soon after the Big Bang,” said Michael Strauss, a professor of astrophysical sciences at Princeton University who is one of the co-authors of the study. “Understanding how black holes can form in the early universe, and just how common they are, is a challenge for our cosmological models.”

Quasar measurements suggest the universe is expanding faster than we thought

Dark energy density seems to be increasing over time, and we’re not really sure why.

The universe is a weird place and it just got a bit weirder. Image credits: NASA / Hubble.

To infinity and beyond

Discovering that the universe is expanding was one of the biggest turning points in astronomy, and science in general. We don’t know how big the universe is, we don’t even know if it’s infinite or not, but we’re pretty certain that it’s expanding. The first evidence emerged in the 1920s, when Alexander Friedmann derived a set of equations known as the Friedmann equations, showing that the universe might expand. The theory really picked up steam a few years later, when Edwin Hubble found that some galaxies appear to be moving away from us.

Hubble also found that not only is the universe is expanding but its expansion is accelerating. This seemed stunning at the time. Not only is the universe getting bigger, but it’s getting bigger, faster. Hubble calculated a universal expansion rate of 500 km/s/Megaparsec, with one megaparsec being equivalent to 3.3 million light years. So for every 3.3 million light-years farther away, the matter where you are is moving away 500 km faster — every second. Subsequent measurements have greatly refined and reduced this value, but there is still some controversy and uncertainty. Most studies, however, agree that the universal expansion rate is around 70km/s/Megaparsec.

But it gets even weirder. Ironically, the universal expansion rate is also called Hubble constant — when it’s anything but constant. Not only do different measurements come up with slightly different values, but when you look in different parts of the universe, you’ll also find different expansion rates.

For instance, the nearby universe, as measured by telescopes like Hubble and Gaia, seems to sport a value of 73 km/s/Mpc. Meanwhile, when the Planck telescope looked towards the distant universe, it came back with a value of just under 70 km/s/Mpc. So Hubble’s constant seems to vary both in time and in space — so much for being a constant.

This is where the new study comes in — but instead of clearing things up, it adds even more mystery.

The brightest of the brightest

Artistic depiction of a distant quasar. Image credits: ESO/M. Kornmesser.

Hubble’s initial studies, like many subsequent measurements, were based on something called redshift. Essentially, as light travels from its original source to us, space is stretched, and the wavelength itself is stretched. This stretch shifts the wavelength towards the redder parts of the spectrum — hence the name “redshift”.

Now, if you want to look at something very distant, you want a very powerful light source. In the new study, researchers focused on the brightest sources of light: quasars.

In a stellar twist of fate, the brightest sources of light go hand in hand with the darkest objects in the universe: supermassive black holes. These black holes, believed to lie at the center of all galaxies, are surrounded by a gaseous accretion disk. As gas falls toward the black hole, energy is released in the form of electromagnetic radiation with incredible power. This phenomenon is called a quasar, and some quasars are thousands of times brighter than the entire Milky Way, which is exactly what you want in this type of study. Quasars are spread across the universe, making them ideal target for multiple measurements.

Astronomers from Durham University in the UK and the Universita degli Studi di Firenze in Italy used observations from 1,600 quasars to calculate the expansion rate of the Universe up to about one billion years after its birth.

When you look at something that’s one light year away, you’re essentially looking into the past and seeing that object as it was one year ago. In this case, the astronomers look around 12 billion years into the past. The strange thing was that the values they found for expansion rates 12 billion years ago were similar to expansion rates reported by previous studies looking at areas from some 8 billion years ago. In other words, two different epochs had the same expansion rate, when really they shouldn’t. There’s nothing in our current arsenal of cosmological knowledge that could convincingly explain that.

“When we combine the quasar sample, which spans almost 12 billion years of cosmic history, with the more local sample of type-Ia supernovas, covering only the past eight billion years or so, we find similar results in the overlapping epochs,” said Dr. Elisabeta Lusso of Durham University, in a statement.

“However, in the earlier phases that we can only probe with quasars, we find a discrepancy between the observed evolution of the Universe and what we would predict based on the standard cosmological model.”

Of course, this is still an early study, which will be thoroughly investigated and replicated — but if it is confirmed, then astrophysicists will have a lot of digging to do to find an explanation.

However, one possible solution, still speculative at this point. could have something to do with the elusive dark energy, a theoretical form of energy postulated to act in opposition to gravity and to occupy the entire universe. Lead author Dr Guido Risaliti, of the Università degli Studi di Firenze, concludes:

“One of the possible solutions to the expansion of the early Universe would be to invoke an evolving dark energy, with a density that increases as time goes by.

The study “Cosmological constraints from the Hubble diagram of quasars at high redshifts” was published in Nature Astronomy.

Oldest black hole found by astronomers — the gargantuan object lies 13 billion light years away from us

The supermassive black hole emerged when the universe was still in its infancy, and it took light carrying its image 13 billion years to reach us. The process which led to its formation is completely unknown.

Artist’s impression of a quasar, an active supermassive black hole with a very high luminosity. Image credits: ESO/M. Kornmesser.

The object was discovered by Eduardo Bañados, an astronomer at Carnegie, as he was looking through multiple all-sky surveys — maps of the distant universe. He was stunned. With a whopping mass, 800 times larger than that of our Sun, the black hole is almost as old as the world itself. The universe is an estimated 13.8 billion years, and this black hole appeared just 690 million years after the Big Bang. It’s the oldest and most distant object we’ve ever seen.

“This is the only object we have observed from this era,” says Robert Simcoe, the Francis L. Friedman Professor of Physics in MIT’s Kavli Institute for Astrophysics and Space Research. “It has an extremely high mass, and yet the universe is so young that this thing shouldn’t exist. The universe was just not old enough to make a black hole that big. It’s very puzzling.”

It’s not just that the black hole formed during these early times, it’s that the universe was undergoing a major shift at that point. During its early stage, the universe went through what is sometimes called the Dark Age — not a metaphor, as it is for the human period, but a truly a dark age as there was no light. The universe was opaque or “foggy” as photons were interacting with early protons and electrons. Light from that age is not visible to us.

Artist’s conceptions of the most-distant supermassive black hole ever discovered, which is part of a quasar from just 690 million years after the Big Bang. It is surrounded by neutral hydrogen, indicating that it is from the period called the epoch of reionization, when the universe’s first light sources turned on. Image: Robin Dienel (Courtesy of the Carnegie Institution for Science), via MIT.

When this black hole was formed, the universe was transitioning from this dark phase into something more similar to what we see today. More and more stars were forming, eventually generating enough radiation to flip hydrogen from neutral (in which electrons are bound to the nucleus) to ionized (in which electrons are freer to interact). This shift allowed light to pass through the cosmos, eventually reaching a tiny blue dot we call Earth and allowing us to research things far away — both in space and in time. Astronomers believe that the black hole was formed in a universe which was about half neutral and half ionized.

“What we have found is that the universe was about 50/50 — it’s a moment when the first galaxies emerged from their cocoons of neutral gas and started to shine their way out,” Simcoe says. “This is the most accurate measurement of that time, and a real indication of when the first stars turned on.”

It’s the first time we are able to detect something this old, and the prospect is exciting as it offers us a unique glimpse into the past. But the massive black hole also comes with a massive mystery. Black holes take on different shapes and sizes, but most often, they form when a massive star collapses onto itself. But at a time when stars were just starting to light up, they wouldn’t have had the time and mass to form such a black hole.

“If you start with a seed like a big star, and let it grow at the maximum possible rate, and start at the moment of the Big Bang, you could never make something with 800 million solar masses — it’s unrealistic,” Simcoe says. “So there must be another way that it formed. And how exactly that happens, nobody knows.”

To make things even more interesting, this appears to be a supermassive black hole — the most massive known objects in the universe, the likes of which are thought to lie at the center of all galaxies. It’s also very active, devouring material at the center of a galaxy and emitting tremendous light in the process. This classifies it as a quasar, and it’s largely what allowed astronomers to discover it.

“Quasars are among the brightest and most distant known celestial objects and are crucial to understanding the early Universe,” said co-author Bram Venemans of the Max Planck Institute for Astronomy in Germany.

The process that led to the creation of this object remains unknown and will no doubt have theorists busy for years to come.

The study was published in Nature.

Scientists discover extremely rare quadruple quasar system

A team of astronomers has discovered a unique system of quadruple quasars. The quartet, discovered at the very edge of the universe, is one of the most massive structures in the known universe.

It’s like winning the lottery – twice. Astronomers have spotted a rare cluster of four quasars—some of the brightest objects in the universe, formed from active black holes. Photograph by Hennawy and Arrigoni Battaia, MPIA.

“On average, quasars are about 100 million light-years apart,” says Joseph Hennawi lead author of a paper on the discovery published Thursday in Science. “The odds against finding four so close together are ten million to one.”

Quasars are the most energetic objects known to man, representing a class of objects called active galactic nuclei. Extremely luminous, the spectra of energy they emit is not seen in any other objects, and a single quasar can be more bright than the entire Milky Way. They’re basically the compact area around a supermassive black hole, swallowing gas and heating it up to immense temperatures.

Quasars were very controversial until the 1980s, but even though there is a general scientific consensus about them now, there are still many things we have yet to discover about them – and extreme occurrences like this one can help astronomers find out more about them. Quite possibly, that our theories are wrong.

“If you find something theory says is very unlikely, “you either have to conclude you got incredibly lucky, or that the theory is flawed,” says Hennawi, of the Max Planck Institute for Astronomy in Heidelberg, Germany.

Seeing two quasars together is very rare, three is even rarer, while four is basically unheard off – it’s a 1 in 10,000,000 chance. To make things even stranger, the four quasars are surrounded by a giant nebula of cool dense hydrogen gas, which also reflects light from the quasars. In addition, both the quartet and the surrounding nebula are found in one of the farthest areas in the known universe, which hosts a surprising amount of matter.

If you put all of these things together, you end up with an extremely unlikely picture.

“The authors found it by investigating the environment of just 29 bright quasars,” says Michele Trenti, a senior lecturer at the University of Melbourne’s School of Physics. “So at face value it seems like winning the lottery with a handful of tickets.”

So like Hennawi said, either “the stars aligned” for this lucky observation to be possible, or something is wrong with our theory of cosmology. If the theory would start to break down, then you’d expect it to break down at extreme objects, like black holes or quasars. Hopefully, future studies will shed light on this issue.

Journal Reference: Joseph F. Hennawi, J. Xavier Prochaska, Sebastiano Cantalupo, Fabrizio Arrigoni-Battaia. Quasar quartet embedded in giant nebula reveals rare massive structure in distant universe. DOI: 10.1126/science.aaa5397

Hubble Discovers Huge Halo Around Andromeda Galaxy

In an article published in the Astrophysical Journal last week, astronomers described a massive halo around the Andromeda Galaxy, extending up close to Earth. The team spotted the halo through NASA’s Hubble Space Telescope and consider it one of the galaxy’s most important features.

The Andromeda Galaxy seen in infrared by the Spitzer Space Telescope, one of NASA’s four Great Space Observatories. Image via Wikipedia.

“Halos are the gaseous atmospheres of galaxies,” Lehner said in a statement released by Notre Dame News. “The properties of these gaseous halos control the rate at which stars form in galaxies.”

The Andromeda Galaxy is located about 2.5 million light years from our own, and it is the nearest galaxy to the Milky Way. It’s the largest galaxy in the Local Group. The halo itself is huge, extending one million light years from the galaxy, containing about as much mass as half the stars in Andromeda.

So how is it that we didn’t discover something as huge as this until now? Well, as the team explains, the gas in the halo is invisible, so they had to rely on an indirect method to view it, using light from 18 different quasars. Quasars are a class of amazing objects – compact regions in the center of a massive galaxy surrounding a central supermassive black hole. They rotate at high speeds and emit electromagnetic radiation which can be detected when they are faced towards the Earth. Imagine a rotating lighthouse – you can see its light when it’s facing you.

“As the light from the quasars travels toward Hubble, the halo’s gas will absorb some of that light and make the quasar appear a little darker in just a very small wavelength range,” the study’s co-author J. Christopher Howk said.

Halos have been observed before, but never before has one so big been imaged. We don’t know if the Milky Way also has a halo; if it does, then the two halos might merge sooner than the two galaxies, and the consequences are still not yet understood.

If you’re worried about the collision of the two galaxies, then you should know that’s only going to happen about 4 billion years from now.

This is an artist's impression of a quasar with a supermassive black hole in the distant universe. Credit: Zhaoyu Li/NASA/JPL-Caltech/Misti Mountain Observatory

Newly discovered ancient Black hole is monstrously big for its age

Astronomers have discovered a humongous supermassive black hole that’s 12 billion times as massive as the Sun. What’s peculiar about it isn’t necessarily its mass – some even bigger black holes have been found – but rather its age. Observations suggest that the black hole 12.8 billion light-years away, which means what scientists are reading and observing what the black hole looked like 12.8 billion years ago. But that’s only 875 million years after the Big Bang, making it the most massive black hole in the early universe – by far!

A cosmic fat kid

This is an artist's impression of a quasar with a supermassive black hole in the distant universe. Credit: Zhaoyu Li/NASA/JPL-Caltech/Misti Mountain Observatory

This is an artist’s impression of a quasar with a supermassive black hole in the distant universe. Credit: Zhaoyu Li/NASA/JPL-Caltech/Misti Mountain Observatory

Black holes, of course, can’t be imaged directly since they like to gobble up anything that comes in their line of gravity. Past a certain threshold, called the event horizon, nothing escapes its grasps – not even light. What the astronomers have imaged, however, is the quasar that surrounds the supermassive black hole. Quasars are some of the brightest and most distant objects we can see. These ultra-bright objects are likely the centers of active galaxies where supermassive black holes reside. As material spirals into the black holes, a large part of the mass is converted to energy. It is this energy that we see. And though smaller than our solar system, a single quasar can outshine an entire galaxy of a hundred billion stars. This specific quasar is 40,000 times as luminous as the entire Milky Way.

The newly discovered quasar SDSS J0100+2802 is the one with the most massive black hole and the highest luminosity among all known distant quasars. The background photo, provided by Yunnan Observatory, shows the dome of the 2.4meter telescope and the sky above it. Credit: Zhaoyu Li/Shanghai Observatory

The newly discovered quasar SDSS J0100+2802 is the one with the most massive black hole and the highest luminosity among all known distant quasars. The background photo, provided by Yunnan Observatory, shows the dome of the 2.4meter telescope and the sky above it. Credit: Zhaoyu Li/Shanghai Observatory

“Before this discovery the most massive black hole known within 1 billion years after the Big Bang was around 5 billion solar mass, less than half the mass of the new detection,” Bram Venemans, research staff scientist with Max Planck Institute for Astronomy in Germany, said for Discovery News.

It’s believed that young block holes from the early universe started off  between 100 and 100,000 times the mass of the sun, then grew by steadily eating more matter or by colliding/merging with other black holes. Neither explanations seemingly account for such a massive black hole at its age.

“How can a quasar so luminous, and a black hole so massive, form so early in the history of the universe, at an era soon after the earliest stars and galaxies have just emerged?” said Xiaohui Fan, Regents’ Professor of Astronomy at the UA’s Steward Observatory. “And what is the relationship between this monster black hole and its surrounding environment, including its host galaxy?

“This ultraluminous quasar with its supermassive black hole provides a unique laboratory to the study of the mass assembly and galaxy formation around the most massive black holes in the early universe.”

What the findings reported in Nature seem to suggest is that the co-evolution of galaxies and their central black holes aren’t necessarily linked together. Not in this case at least.

Distant Black Hole Spins at Half the Speed of Light

Credits: X-RAY: NASA/CXC/UNIV OF MICHIGAN/R.C.REIS ET AL; OPTICAL: NASA/STSCI

About half of the Universe’s lifetime ago, it was feasting time for supermassive black holes – they were eating galaxies left and right, a new study might suggest. Taking advantage of a galaxy which acts like a natural zoom lens in space, astronomers have analyzed a black hole powering a quasar about 6 billion light years from Earth.

“The ‘lens’ galaxy acts like a natural telescope, magnifying the light from the faraway quasar,” University of Michigan astronomer Rubens Reis explains in a paper published in this week’s Nature.

Quasars and black holes

Quasars are amazing things! They are the most energetic and distant members of a class of objects called active galactic nuclei (AGN). The general consensus now (while there is still some debate) is that quasars are compact regions surrounding the supermassive black holes at the center of some galaxies. More than 200,000 quasars are known.

Analyzing four magnified images created by the lens galaxy, astronomers found that the quasar’s black hole is spinning at half the speed of light.

When it comes to black holes spinning, it’s all about the “feeding”. Black holes of course are so massive that they attract and “devour” anything – even light can’t escape from them, that’s why they’re black. The thing is, the more they eat, the faster they spin – so a black hole that’s been destroying lots of stuff would be spinning really fast. How fast? Let’s say half the speed of light fast.

“If the mass accretion was more messy it would suggest that the black hole would have a lower spin,” astronomer Mark Reynolds, also with University of Michigan, explained.” What we found in this system is that it’s spinning very rapidly,” Reynolds said, consuming mass equivalent to about one sun per year.

Just so you can get a sens of the scale we’re discussing here, we’re not talking about eating a planet or two – we’re talking about eating an entire galaxy, or perhaps even more. Astronomers believe that the black hole probably accumulated two galaxies colliding with each other, conveniently funneling the resulting gas and matter.

“This is the first time that we’ve been able to push out to this type of distance by using the gravitational lensing effect. We hope … to carry out similar studies on other (more distant) galaxies. Then we can begin to really start relating the black hole to the actual galaxy it’s in, how many mergers happened and things like that,” Reynolds said.

It’s still not clear if this kind of thing is common, or if researchers stumbled upon an exception.

“Different theories of galaxy evolution predict a different rate of mergers, and a different process of gas inflow into the center of galaxies,” Guido Risaliti, with the INAF Arcetri Astrophysical Observatory in Florence, Italy, wrote in an email to Discovery News. “These processes, in turn, determine the final black hole spin. So knowing the distribution of supermassive black hole spins is a way to constrain the way they were formed, and so, ultimately, the way their host galaxies formed and evolved,” Risaliti wrote.

Black hole bonanza discovered in neighboring galaxy

Astronomers have discovered 26 likely black holes in the Andromea Galaxy – the biggest number of black holes ever found in a galaxy except for our own.

andromeda galaxy

Black holes are pretty difficult to detect, because they emit no light of their own – they are only observed by light given off by material which falls into them. Just as a sidenote, supermassive black holes, the gravitational monsters which lie at the centers of most galaxies are very easy to detect, due to their very bright nearby surroundings; this doesn’t apply for smaller ones, however.

We always tend to think of black holes as some very distant bodies, lying many light years away from us – but we tend to forget that there’s plenty of then in our very own galaxy – and we’ve just started finding more.

“While we are excited to find so many black holes in Andromeda, we think it’s just the tip of the iceberg,” Robin Barnard, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., said in a statement. “Most black holes won’t have close companions and will be invisible to us.”

Most of these newfound black holes are fairly small, with about 5-10 times more mass than the sun (compared to the one at the center of the Milky Way, which has about 4.1 million more). Out of these new findings, seven of them lay very close to the center of the Andromeda Galaxy – more than the number we have detected near the center of the Milky Way.

“We are particularly excited to see so many black hole candidates this close to the center, because we expected to see them and have been searching for years,” Barnard said.

As exciting as it is, this was no surprise for astrophysicists, who were expecting Andromeda to have more black holes, considering how its bulge, the big massed up star cluster near its center is larger than our galaxy’s.

“When it comes to finding black holes in the central region of a galaxy, it is indeed the case where bigger is better,” co-author Stephen Murray of Johns Hopkins University and the Center for Astrophysics said in a statement. “In the case of Andromeda, we have a bigger bulge and a bigger supermassive black hole than in the Milky Way, so we expect more smaller black holes are made there as well.”

The new black holes were discovered using NASA’s Chandra X-ray Observatory. Researchers used over 100 separate observations over the course of 13 years to make the detection.

Obese black holes outshone stars in earliest galaxies

 

early galaxyEarly galaxies were very different from those we see today – it was overgrown black holes, and not stars that lit them up, claims a new study; in it, it is suggested that these obese black holes were numerous and bright enough that we should be able to detect them now, billions of years after they shone.

Born fat?

But if we’re dealing with this kind of black holes, one can only wonder – were they born fat, or did it just happen gradually? They could have been born obese, from massive clouds of atomic hydrogen, up to a hundred million times as massive as the Sun, which collapsed into themselves.

Now Bhaskar Agarwal at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, and colleagues say we should be able to see if this was indeed the case – galaxies with few stars, each dominated by a giant black hole lit up by the same mechanism that illuminates quasars.

Wait, what’s a quasar?

That’s a big question. Most if not all galaxies have supermassive black holes at their centers. A quasar is the extremely luminous and very energetic area that surrounds this central supermassive black hole.

Could the same mechanism which powers up quasars light the early black holes? Through a combination of computer simulations and mathematical analysis, Agarwal and his collaborators suggest that there may have been many such obese black hole galaxies just a few hundred million years after the big bang.

Source

An infrared image of the triple quasar system made using the 3.5-m aperture telescope of the Calar Alto Observatory. The three quasars are labelled A, B and C. (Credit: Emanuele Paolo Farina)

Rare and elusive triple quasar system discovered

An infrared image of the triple quasar system made using the 3.5-m aperture telescope of the Calar Alto Observatory. The three quasars are labelled A, B and C. (Credit: Emanuele Paolo Farina)

An infrared image of the triple quasar system made using the 3.5-m aperture telescope of the Calar Alto Observatory. The three quasars are labelled A, B and C. (Credit: Emanuele Paolo Farina)

This is only the second time ever that astronomers have managed to identify a triple quasar system – a highly elusive and very difficult to observe phenomenon. The international team of researchers identified and described the triple quasar system named QQQ J1519+0627 in a paper published in the Oxford University Press journal Monthly Notices of the Royal Astronomical Society. 

Quasars are some of the most energetic and brightest objects in the Universe, residing at the center of galaxies around a black hole. Sometimes quasars can form a system, held together by gravity, and are believed to be product of galaxies colliding. Since they’re so energetic, however, observing binary, even triple quasar systems is a very difficult astronomical feat since instruments have a hard time distinguishing individual bodies from one another. Moreover, such phenomena are presumed to be extremely rare.

It’s no wonder then that this triple quasar system, located at a whooping 9 billion-light years away (meaning the light was emitted when the Universe was only a third of its current age), is only the second one found. In order to confirm that indeed three distinct quasar bodies form the system, the team of astronomers led by Emanuele Farina of the University of Insubria in Como, Italy, combined telescope observations advanced modelling.

Furthermore, it was found that two of the three members are closer to each other than the third, hinting that the system was likely formed by the interaction between the two adjacent quasars, but was probably not triggered by interaction with the more-distant third quasar. What’s rather peculiar, however, is the lack of ultra-luminous infrared emissions that typically spur from a certain type of galaxies quasars like to call home. This has prompted the researchers to believe this triplet quasar system is part of some larger structure that is still undergoing formation.

“Honing our observational and modelling skills and finding this rare phenomenon will help us understand how cosmic structures assemble in our universe and the basic processes by which massive galaxies form,” Fumagalli said.

“Further study will help us figure out exactly how these quasars came to be and how rare their formation is,” Farina added.

 

quasar-largest

Largest known structure in the Universe discovered by scientists

quasar-largest

Astronomers from Britain’s University of Central Lancashire have recently published a landmark paper that describes the largest known structure in the Universe, a group of quasars so large it spans 4 billion light-years across at its longest end. The study holds broader consequences, not just because of the encountered astronomical milestone,  since it challenges  Albert Einstein’s Cosmological Principle, the assumption that the universe looks the same from every point of view, and which has stood in place for almost a century.

Quasars are the brightest objects in the Universe. They’re actually supermassive black holes surrounded by an accretion disk. When matter absorbed by the black hole located at the center of the galaxy reaches a critical level, a gigantic collision of matter occurs resulting  in a gigantic explosive output of radiation energy and light. Quasars are very distant objects, from much earlier in the Universe’s history.

Since a few decades ago scientists have known that quasars tend to group with another in structures of surprising size called  large quasar groups or LQGs. The recent quasar group discovered by the British astronomers is simply gigantic even by cosmological standards with a typical dimension of 1.7 billion light-years. However, because the structure is elongated it measures at its longest section a whooping 4 billion light-years. For a bit of perspective, the LGC is about 1,600 times as big as our galaxy, the Milky Way, which houses between 200 and 400 billion stars.

“While it is difficult to fathom the scale of this LQG, we can say quite definitely it is the largest structure ever seen in the entire universe,” Roger Clowes, leader of the research team, said in a statement. “This is hugely exciting – not least because it runs counter to our current understanding of the scale of the universe.”

Here’s lies the predicament, though. The current modern theory of cosmology suggests that astrophysicists shouldn’t be able to find a structure larger than 1.2 billion light years. The theory states that on very large scales the universe looks the same no matter where you observe it from.

“Our team has been looking at similar cases which add further weight to this challenge and we will be continuing to investigate these fascinating phenomena,” continued Clowes.

The findings were detailed in the journal of the Royal Astronomical Society.

source

An artist’s rendering of the quasar 3C 279 (credit: European Southern Observatory)

First stars formed 750 million years after the Big Bang

An artist’s rendering of the quasar 3C 279 (credit: European Southern Observatory)

An artist’s rendering of the quasar 3C 279 (credit: European Southern Observatory)

Determining when stars first started to form through out the early Universe is a matter of great importance for astronomers and astrophysicists looking to understand how the cosmos evolved from its incipient point of origin. Recently, researchers at MIT who have been studying the most distant quasar observed so far found  no discernible trace of heavy elements, such as carbon and oxygen. Their findings suggest that stars had yet to be born 750 million years after the Big Bang.

The elements are only formed by stars –  essentially we all come from stars. If these basic building blocks aren’t visible then  the quasar dates to an era nearing that of the universe’s first stars.

After the Big Bang massive amounts of matter and energy were flung, leading to the expansion of the early Universe. In the minutes following the explosion, protons and neutrons collided in nuclear fusion reactions to form hydrogen and helium. Once the Universe cooled, fusion ceased along with the generation of  these primordial elements. It would be until the first stars appeared that heavy elements such as oxygen or carbon could be synthesized.

Lack of these elements in observations suggests that stars hadn’t been formed during that phase of the Universe. So far, the farthest astronomers have gone to study the light of distant objects was 11 billion years – the Universe is 13.7 billion years old, and each time heavy elements were found. Last year scientists discovered  the earliest quasar found so far, which provided a snapshot of our universe during its infancy, a mere 750 million years after the initial explosion that created the universe.

“The first stars will form in different spots in the universe … it’s not like they flashed on at the same time,” says Robert Simcoe, an associate professor of physics at MIT. “But this is the time that it starts getting interesting.”

“[The astrophysics community] sort of hit this wall,” says Simcoe, an astrophysicist at MIT’s Kavli Institute for Astrophysics and Space Research. “When this [quasar] was discovered, we could sort of leapfrog further back in time and make a measurement that was substantially earlier.”

Before stars shone bright

An artist’s rendering of how the most distant quasar found to date would have appeared just 770 million years after the Big Bang (credit: European Southern Observatory/M. Kornmesser)

An artist’s rendering of how the most distant quasar found to date would have appeared just 770 million years after the Big Bang (credit: European Southern Observatory/M. Kornmesser)

Recently MIT astronomers pointed the Magellan Telescope, a massive ground-based telescope in Chile, which they fitted with a carefully designed spectrometer, towards the quasar to study its light spectrum. Each element gives of a pattern, based on how it characteristically absorbs light. Based on this, the scientists found evidence of hydrogen, but no oxygen, silicon, iron or magnesium in the light data.

“[The birth of the first stars] is one of these important moments in the history of the universe,” Simcoe says. “It went from looking like the early universe, which was just gas and dark matter, to looking like it does today, where there are stars and galaxies … it’s the point when the universe started to resemble what it looks like today. And it’s sort of amazing how early that happens. It didn’t take long.”

Other scientists, like John O’Meara, an associate professor of physics at St. Michael’s College in Vermont, believe that more observations of distant quasars is needed in order to confirm the findings.

“Prior to this result, we have not seen regions of the universe this old and devoid of heavy elements, so there was a missing link in our understanding of how the elemental content of the universe has evolved with time,” O’Meara adds. “[This] discovery possibly provides such a rare environment where the universe had yet to form stars.”

Results were published in the journal Nature.

source: MIT

Artist's impression shows the material ejected from the region around the supermassive black hole in the quasar SDSS J1106+1939. (c) ESO

Most powerful quasar outflow detected is two trillion times more energetic than the sun

Astronomers using ESO‘s Very Large Telescope (VLT) have discovered the most powerful quasar outflow discovered to date – five times more energetic than the previous record holder.

Dubbed SDSS J1106+1939, the quasar outflow is at least equivalent to two million million times the power output of the Sun or 100 times higher than the total power output of the Milky Way galaxy. The newly discovered outflow lies about a thousand light-years away from the supermassive black hole at the heart of the quasar. This is a beast, make no mistake!

Artist's impression shows the material ejected from the region around the supermassive black hole in the quasar SDSS J1106+1939. (c) ESO

Artist’s impression shows the material ejected from the region around the supermassive black hole in the quasar SDSS J1106+1939. (c) ESO

Quasars are the most energetic cosmic objects in the Universe, and are powerful by black holes at the center of galaxies. Gravitational stresses and intense friction outside of the event horizon of black holes causes accretion of material around them, which in term power quasars that shovels massive amounts of escaping energy into cosmos.

According to Hubble’s law the redshift shows that quasars are very distant and, because of their distance, much older than our universe.

“I’ve been looking for something like this for a decade,” says team leader Nahum Arav from Virginia Tech, “so it’s thrilling to finally find one of the monster outflows that have been predicted!”

It is believed quasars and their outflows play a vital role in the formation of galaxies. Quasars may influence how the mass of a galaxy is linked to its central black hole mass, and why there are so few large galaxies in the Universe. Still, these issues and many more, are yet to be resolved. Our understanding of quasars has come a long way in the past few decades, and it is through milestone discoveries such as that of J1106+1939 that we will further expand our knowledge.

Findings were detailed in the The Astrophysical Journal.

Universe Expansion Dark Energy

Dark energy influence on the Universe like a roller coster ride

Universe Expansion Dark Energy

(c) NASA

Scientists with the  Sloan Digital Sky Survey (SDSS-II) have used a novel technique to peer through the nature of dark energy as far as ten billion years ago and measure the  three-dimensional structure of the distant Universe. Tracing this 3-D map scientists were able to assess the influence of dark energy over time, which might help unravel the mysteries of this repulsive force.

For the past five billion years, the Universe expansion rate has been speeding up, a phenomenon attributed to dark energy by astronomers. In the early phase of the Universe, however, a few billion years after the Big Bang, this mysterious force did not have a dominant role as  gravity actually held sway, decelerating cosmic expansion.

“We know very little about dark energy but one of our ideas is that it is a property of space itself – when you have more space, you have more energy,” explained Dr Matthew Pieri, a BOSS team-member.

“So, dark energy is something that increases with time. As the Universe expands, it gives us more space and therefore more energy, and at some point dark energy takes over from gravity to end the deceleration and drive an acceleration,” the Portsmouth University, UK, researcher said.

The new measurement is based on data from the Baryon Oscillation Spectroscopic Survey (BOSS), one of the four surveys that make up SDSS-III, gathered using a novel technique called  “baryon acoustic oscillations” (BAO).  This technique uses small variations in matter left over from the early Universe as a “standard ruler” to compare the size of the Universe at various points in its history.

In order for this technique to work, scientists had to study very distant objects. However, very distant objects, like ancient, far away galaxies are faint and difficult to survey, so the astronomers decided to look after quasars, one of the most energetic objects in the Universe, to map the spread of hydrogen gas clouds in space.

Before the quasars’ electromagnetic radiation emissions reach Earth, they encounter clouds of hydrogen. Part of the light becomes thus absorbed, and the pattern of absorption betrays how the density of gas varies with distance along the line of sight to the telescope.

Measuring this absorption – a phenomenon known as the Lyman-alpha Forest – yields a detailed picture of the gas between us and the quasar.

“It’s a cool technique, because we’re essentially measuring the shadows cast by gas along a single line billions of light-years long,” says Anze Slosar of Brookhaven National Laboratory.

“The tricky part is combining all those one-dimensional maps into a three-dimensional map. It’s like trying to see a picture that’s been painted on the quills of a porcupine.”

Last year, the team of astronomers used data from 10,000 quasars gathered by the SDSS-III’s Baryon Oscillation Spectroscopic Survey (BOSS) to make the first large-scale map of the structure of the faraway “Lyman-alpha forest” gas. However, the resolution wasn’t high enough to detect the subtle variation of baryon acoustic oscillations. Now in their latest survey, the scientists build a map of 50,000 quasars that shows the distribution of hydrogen gas clouds reaching 11 billion light-years away  – just two billion years after the Big Bang itself.

Universe expansion is like a roller coaster ride

“If we think of the Universe as a roller coaster, then today we are rushing downhill, gaining speed as we go,” says Nicolas Busca of the Laboratoire Astroparticule et Cosmologie of the French Centre National de la Recherche Scientifique (CNRS), one of the lead authors of the study.

“Our new measurement tells us about the time when the Universe was climbing the hill – still being slowed by gravity.”

Equipped with this high detail map of BAOs, the scientists were able to paint a picture of how the Universe evolved through out history. For the first time, we see how dark energy worked at a time before the Universe’s current acceleration started.

The BOSS findings show that the expansion of the Universe slowed down some 11 billion years ago as a tug of war ensued  between the attractive gravitational forces of galaxies. As the Universe continued to expand,  the constant repulsive force of dark energy began to dominate as matter was diluted by the expansion of space. This is consistent with current Universe expansion theories.

“No technique has ever been able to probe this ancient era before,” says BOSS principal investigator David Schlegel of the Lawrence Berkeley National Laboratory.

“Back then, the expansion of the Universe was slowing down; today, it’s speeding up. How dark energy caused the transition from deceleration to acceleration is one of the most challenging questions in cosmology.

More than eighty years since Edwin Hubble and Georges Lemaitre first measured the expansion rate of the nearby Universe, the SDSS-III has made the same measurement of the expansion rate of the Universe 11 billion years ago. Currently, the BOSS project is only completed by a third. In the few years, scientists plan to map the locations of a million-and-a-half galaxies and more than 160,000 quasars. By the time SDSS-III is complete, it will have helped transform the Lyman-alpha forest technique from a risky idea into a standard method by which astronomers explore the nature of the faraway Universe, the authors involved in the study claim .

Findings were published in the journal Astronomy and Astrophysics.

This is a still image from a video fly-through of the SDSS-III galaxies mapped in Data Release 9. (c) SDSS

Largest 3-D map of the universe released by the SDSS [VIDEO]

This is a still image from a video fly-through of the SDSS-III galaxies mapped in Data Release 9. (c) SDSS

This is a still image from a video fly-through of the SDSS-III galaxies mapped in Data Release 9. (c) SDSS

Previously, we shared the largest and, respectively, most detailed 3-D maps of the Universe released by the Sloan Digital Sky Survey. Now the survey has released a new, massive update to the map, again, making it the largest 3-D map of the Universe, which pinpoints the locations and distances of over a million galaxies. Were you to envision this 3-D map as a cube, its side would be four billion light-years in distance – yes, this is massive data!

Time capsules? Well, with data from the SDSS one can take a trip down memory lane billion of years back with ease. And by making this data freely available to the public, the survey hopes that astronomers from all around the world can now contribute with distinct findings of their own. In fact, considering the sheer volume of stellar information available, it should keep them busy enough for quite some time.

Improvements to the previously released version include:

  • More than 800,000 new galaxy, quasar and stellar spectra
  • Improved stellar parameters for SEGUE and SDSS-I/II stars
  • Improved astrometric calibration
  • Several small changes to catalog data from DR7 and DR8

It’s worth considering, though, that the data released thus far has been amounted during a mere two years of study, out of the whole six years of the project. Expect an even refined and detailed version to pop-up regularly. The project is called the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), which will measure the positions of massive galaxies up to six billion light-years away, as well as quasars – giant black holes actively feeding on stars and gas – up to 12 billion light-years from Earth.

“What really makes me proud of this survey is our commitment to creating a legacy for the future,” says Michael Blanton, a New York University physics professor who led the team that produced the map. “Our goal is to create a map of the universe that will be used long after we are done, by future generations of astronomers, physicists, and the general public.”

Though barely mentioned, the survey’s goal is most likely that of estimating how much of the Universe is made of “dark matter” and “dark energy,” the even more mysterious force that drives the accelerating expansion of the universe.

“Dark matter and dark energy are two of the greatest mysteries of our time,” said David Schlegel of Lawrence Berkeley National Laboratory, the principal investigator of BOSS. “We hope that our new map of the universe can help someone solve the mystery.”


“This YouTube video shows the positions of the 900,000 luminous galaxies used in these studies. Each green dot represents one galaxy. The image covers a redshift range from 0.25 to 0.75, reaching to six billion years ago. The rotation of the image provides a view that shows what the distribution would look like from all sides. Click on the movie to start or stop playing the movie.”

To view patches of the map, you need to follow instructions here, which include downloading a software and getting adjusted with the rather intuitive package.

This deep image shows the region of the sky around the quasar HE0109-3518. The quasar is labelled with a red circle near the centre of the image. The energetic radiation of the quasar makes dark galaxies glow, helping astronomers to understand the obscure early stages of galaxy formation. The faint images of the glow from 12 dark galaxies are labelled with blue circles Click for ZOOM. (C) ESO

First evidence of dark galaxies from the early Universe spotted

An international team of astronomers may have come across the first sound evidence testifying the existence of dark galaxies – cosmic bodies from the early Universe long theorized by scientists in the past, but never before confirmed until now.

Dark galaxies are small, gas-rich galaxies that are very inefficient at forming stars themselves. Their name comes from the fact that they’re void of stars, thus no light is emitted, making them theoretically invisible. Scientists consider dark galaxies to have played a major role in star-rich galaxy formation during the early Universe expansion, feeding neighboring galaxies with precious gas required to birth stars.

Since dark galaxies don’t emit any light, confirming their existence has been always extremely difficult for scientists attempting such a feat. Previous studies of small absorption dips in the spectra of background light sources were thought to have hinted at dark galaxies, but this newly presented research is the first to provide rather tantalizing proof.

Using the European Southern Observatory’s Very Large Telescope (VLT) in northern Chile, the researchers saw the extremely faint fluorescent glow of the dark galaxies.

“Our approach to the problem of detecting a dark galaxy was simply to shine a bright light on it,” says Simon Lilly of ETH Zurich.

“We searched for the fluorescent glow of the gas in dark galaxies when they are illuminated by the ultraviolet light from a nearby and very bright quasar. The light from the quasar makes the dark galaxies light up in a process similar to how white clothes are illuminated by ultraviolet lamps in a night club.”

This deep image shows the region of the sky around the quasar HE0109-3518. The quasar is labelled with a red circle near the centre of the image. The energetic radiation of the quasar makes dark galaxies glow, helping astronomers to understand the obscure early stages of galaxy formation. The faint images of the glow from 12 dark galaxies are labelled with blue circles  Click for ZOOM. (C) ESO

This deep image shows the region of the sky around the quasar HE0109-3518. The quasar is labelled with a red circle near the centre of the image. The energetic radiation of the quasar makes dark galaxies glow, helping astronomers to understand the obscure early stages of galaxy formation. The faint images of the glow from 12 dark galaxies are labelled with blue circles Click for ZOOM. (C) ESO

The telescope was directed towards a patch of the sky, around the bright quasar HE 0109-3518, where it mapped the region and looked for ultraviolet light released by hydrogen gas when subjected to radiation. Quasars are the brightest and most energetic objects in the Universe. The exposure time was enormous, but in the end it paid out for the astronomers.

“After several years of attempts to detect fluorescent emission from dark galaxies, our results demonstrate the potential of our method to discover and study these fascinating and previously invisible objects,” study lead author Sebastiano Cantalupo, from the University of California, Santa Cruz, said in a statement.

Their initial round of data returned 100 possible gaseous objects which lie within a few million light-years of the quasar. Eliminating objects where the emission might have been powered by internal star-formation in neighborliness galaxies, the team of researchers narrowed the list down to 12.

Also, the researchers were able to determine some of the dark galaxies’ properties. They speculate the mass of the gas in dark galaxies is about one billion times that of the sun, and that they’re 100 times less efficient at forming stars than most galaxies of the time. Their exact composition hasn’t been determined yet, since there’s no conclusive way of determining it. However, theoretically they’re composed of hydrogen, dust and dark matter.

“Our observations with the VLT have provided evidence for the existence of compact and isolated dark clouds,” Cantalupo said. “With this study, we’ve made a crucial step towards revealing and understanding the obscure early stages of galaxy formation and how galaxies acquired their gas.”

This research was presented in a paper entitled “Detection of dark galaxies and circum-galactic filaments fluorescently illuminated by a quasar at z=2.4”, by Cantalupo et al. to appear in Monthly Notices of the Royal Astronomical Society.

source: ESO

Quasar Faint Light

Quasars “snack” regularly, instead of “feasting in one gulp”

Artist's rendering of ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun. (c) ESO/M. Kornmesser

Artist's rendering of ULAS J1120+0641, a very distant quasar powered by a black hole with a mass two billion times that of the Sun. (c) ESO/M. Kornmesser

Quasars are some of the brightest objects in the Universe. Their formed after black holes devour captured material, like  gas dust and stars that come too close, and release bright light that can be seen across the universe. Most of the popular astronomy today is orientated towards the particularly extremely bright quasars; those formed in a singular event consisting of the merger of a black holes with other galaxies that drive huge streams of gas and dust into their centers.

A new NASA survey however has found that more often than not, there are fainter quasars that thrive in normal-looking spiral galaxies, making the bulk of the Universe’s quasar population. A census of 30 quasar host galaxies was conducted by  Hubble and Spitzer. Of these, 26 of the host galaxies show no particular sign of a cosmic collision with neighbors, an event usually signaled by distorted shapes. Of the rest,  only one galaxy in the sample shows evidence of an interaction with another galaxy.

“The brilliant quasars born of galaxy mergers get all the attention because they are so bright and their host galaxies are so messed up,” Yale University astronomer Kevin Schawinski said in a statement. “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.”

Quasar Faint Light

Four photos merged together taken by the Hubble Space Telescope, each depicting galaxies kept at bay by quasars at their center. Three of these galaxies (top right, bottom left, and bottom right) are normal and show no signs of past collisions, while the top left galaxy's irregular shape suggests it collided with a neighbor. (c) NASA, ESA

The quasars were observed in infrared light, which can pierce through the dust that often shrouds galaxies in optical light. They’re estimated to have existed roughly 8 billion to 12 billion years ago, a time when black hole growth was at a peak.

Black holes are slow eaters, not excited gobblers. No word on table manners, though

What makes this discovery really important is the fact that it now offers substantial proof, backing the claim that the growth of most massive black holes in the early universe was fueled by small, long-term events rather than dramatic short-term major mergers. What does it take to make a quasar, though? According to the NASA researchers, typically a black hole doesn’t need too much gas to unleash a quasar.

“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.”

Not very much is known about quasar, particularly because they’re so difficult to observe and study. This might change once with the launch of the James Webb Telescope, a massive, cutting-edge space telescope designed to orbit 1 million miles from Earth, where it would observe the mid-infrared portion of the electromagnetic spectrum.

To get to the heart of what kinds of events are powering the quasars in these galaxies, we need the Webb telescope. Hubble and Spitzer have been the trailblazers for finding them.”

Findings were published in the journal Monthly Notices of the Royal Astronomical Society.

via space.com