Astrophysicists announce discovery that could rewrite story of how galaxies die

(THIS ARTICLE IS COURTESY OF PHYSICS.ORG)

 

Astrophysicists announce discovery that could rewrite story of how galaxies die

Astrophysicist announces her discovery that could rewrite story of how galaxies die
This artist conception depicts an energetic quasar which has cleared the center of the galaxy of gas and dust, and these winds are now propagating to the outskirts. Soon, there will be no gas and dust left, and only a luminous blue quasar will remain. Credit: Michelle Vigeant

At the annual meeting of the American Astronomical Society in St. Louis, Missouri, Allison Kirkpatrick, assistant professor of physics and astronomy at the University of Kansas, will announce her discovery of “cold quasars”—galaxies featuring an abundance of cold gas that still can produce new stars despite having a quasar at the center—a breakthrough finding that overturns assumptions about the maturation of galaxies and may represent a phase of every galaxy’s lifecycle that was unknown until now.

Her news briefing, entitled “A New Population of Cold Quasars,” takes place Wednesday, June 12, on the 2nd floor of the St. Louis Union Station Hotel.

A quasar, or “quasi-stellar radio source,” is essentially a  on steroids. Gas falling toward a quasar at the center of a galaxy forms an “accretion disk” which can cast off a mind-boggling amount of electromagnetic energy, often featuring luminosity hundreds of times greater than a typical galaxy. Typically, formation of a quasar is akin to galactic retirement, and it’s long been thought to signal an end to a galaxy’s ability to produce .

“All the gas that is accreting on the black hole is being heated and giving off X-rays,” Kirkpatrick said. “The wavelength of light that you give off directly corresponds to how hot you are. For example, you and I give off infrared light. But something that’s giving off X-rays is one of the hottest things in the universe. This gas starts accreting onto the black hole and starts moving at relativistic speeds; you also have a magnetic field around this gas, and it can get twisted up. In the same way that you get solar flares, you can have jets of material go up through these magnetic field lines and be shot away from the black hole. These jets essentially choke off the gas supply of the galaxy, so no more gas can fall on to the galaxy and form new stars. After a galaxy has stopped forming stars, we say it’s a passive dead galaxy.”

But in Kirkpatrick’s survey, about 10 percent of  hosting accreting supermassive  had a supply of cold gas remaining after entering this phase, and still made new .

Astrophysicist announces her discovery that could rewrite story of how galaxies die
An optical blue quasar at a lookback time of 7 billion years (this is not a nearby galaxy). Normally, something like this would not have infrared emission. Credit: Dark Energy Camera Legacy Survey DR7/NOAO

“That in itself is surprising,” she said. “This whole population is a whole bunch of different objects. Some of the galaxies have very obvious merger signatures; some of them look a lot like the Milky Way and have very obvious spiral arms. Some of them are very compact. From this diverse population, we then have a further 10 percent that is really unique and unexpected. These are very compact, blue, luminous sources. They look exactly like you would expect a supermassive black hole to look in the end stages after it has quenched all of the star formation in a galaxy. This is evolving into a passive elliptical galaxy, yet we have found a lot of cold gas in these as well. These are the population that I’m calling ‘cold quasars.'”

The KU astrophysicist suspected the “cold quasars” in her survey represented a brief period yet to be recognized in the end-phases of a galaxy’s lifespan—in terms of a human life, the fleeting “cold quasar” phase may something akin to a galaxy’s retirement party.

“These galaxies are rare because they’re in a transition phase—we’ve caught them right before star formation in the galaxy is quenched and this transition period should be very short,” she said.

Kirkpatrick first identified the objects of interest in an area of the Sloan Digital Sky Survey, the most detailed digital map of the universe available. In an area dubbed “Stripe 82,” Kirkpatrick and her colleagues were able to visually identify quasars.

“Then we went over this area with the XMM Newton telescope and surveyed it in the X-ray,” she said. “X-rays are the key signature of growing black holes. From there, we surveyed it with the Herschel Space Telescope, a far infrared telescope, which can detect dust and gas in the host galaxy. We selected the galaxies that we could find in both the X-ray and in the infrared.”

Astrophysicist announces her discovery that could rewrite story of how galaxies die
The dust emission of the same blue-quasar galaxy. It is surprisingly bright — in fact, it’s one of the brightest objects in the field, indicating a lot of dust. Due to the resolution of the telescope, we cannot see what that dust actually looks like. Credit: Herschel/ESA

The KU researcher said her findings give scientists new understanding and detail of how the quenching of star formation in galaxies proceeds, and overturns presumptions about quasars.

“We already knew quasars go through a dust-obscured phase,” Kirkpatrick said. “We knew they go through a heavily shrouded phase where dust is surrounding the supermassive black hole. We call that the red quasar phase. But now, we’ve found this unique transition regime that we didn’t know before. Before, if you told someone you had found a luminous quasar that had a blue optical color—but it still had a lot of dust and gas in it, and a lot of star formation—people would say, ‘No, that’s not the way these things should look.'”

Next, Kirkpatrick hopes to determine if the “cold quasar” phase happens to a specific class of galaxies or every galaxy.

“We thought the way these things proceed was you have a growing black hole, it’s enshrouded by dust and gas, it begins to blow that material out,” she said. “Then it becomes a luminous blue object. We assumed when it blew out its own gas, it would blow out its host gas as well. But it seems with these objects, that’s not the case. These have blown out their own dust—so we see it as a blue object—but they haven’t yet blown out all of the dust and gas in the host galaxies. This is a transition phase, let’s say of 10 million years. In universal timescales, that’s really short—and it’s hard to catch this thing. We’re doing what we call a blind survey to find objects we weren’t looking for. And by finding these objects, yes, it could imply that this happens to every galaxy.”

Black hole BOMBSHELL: NASA astronomer hints universe could be a HOLOGRAM

(THIS ARTICLE IS COURTESY OF THE UK EXPRESS NEWS)

 

Black hole BOMBSHELL: NASA astronomer hints universe could be a HOLOGRAM

BLACK holes could hold all of the secrets of the universe and prove once and for all we live in a “giant hologram”, a NASA astronomer has spectacularly claimed.

NASA claim that WATER is present on the moon’s surface

Pause

Mute

Current Time 1:12
/
Duration 1:41
Loaded: 0%

Progress: 0%

FacebookTwitterShareFullscreen

Black holes are incredible wells of gravity, where the force of attraction traps everything including light. Black holes are often found at the hearts of galaxies and up until April this year have been purely theoretical. In April, astronomers behind the Event Horizon Telescope (EHT) collaboration photographed the first ever shadow of a black hole millions of light-years from Earth. But little is still known about the exact nature of these terrifying objects and speculation is rampant.

This is why astronomer Michelle Thaller, who is the assistant director of Science Communications at , said dark holes challenge our understanding of physics.

The  experts appeared in a science video for Big Think, where she discussed the idea black holes are key to cracking the secrets of the universe.

And perhaps most shockingly, the astronomer suggested the universe in which we live is nothing more than a two-dimensional hologram.

Dr Thaller said: “Things are stopped in time as they fell into the black hole. And right at the boundary, there is almost kind of a sphere, a two-dimensional surface that somehow contains all the information about what’s inside the black hole.

READ MORE: 

Black hole shock: The universe is a hologram

Black hole SHOCK: Black holes and the universe could be a hologram in a shock twist (Image: GETTY)

“And this reminds people of something that humans invented, called a hologram.

“Now, a hologram is a two-dimensional object. You can make it out of glass or a piece of film. And you shine a light through it and all of a sudden, there seems to be three-dimensional projections.

“And the idea is that we are looking at some fundamental way the universe stores information. Around a black hole, where space and time have been crushed out of existence, could there be a shell of information, something like a hologram?”

But how does this cosmic revelation suggest the universe at large is a form of a hologram?

READ MORE: 

According to Dr Thaller, black holes could be a miniaturised representation of how the universe works on a big scale.

This all sounds incredibly strange

Dr Michelle Thaller, NASA

In this scenario, all of the information in the universe is spread out across a 2D surface and we could be part of it.

But the astronomer said this does not in any way imply intent or creative design behind the hologram.

She said: “We’re just talking about the universe may really be information contained in a two-dimensional structure, not the three dimensions that we’re aware of now. This all sounds incredibly strange.

READ MORE: 

Black hole in space: Universe is a hologram

Black holes are incredible wells of gravity peppered throughout the cosmos (Image: GETTY)

Black hole: Dr Michelle Thaller

Black hole: Dr Michelle Thaller said the universe could be two-dimensional information (Image: BIG THINK)

“I’m always a little bit afraid to talk about it. But I think that the thing to really kind of gain from this is that black holes are staring us right in the face. We’re now observing them.

“They’re right there. And we cannot really describe how the universe should work with one of these things. They don’t make sense.”

On April 10, 2019, the EHT collaboration published the world’s first ever photograph of a distant black hole at the heart of galaxy Messier 87.

The historic achievement confirmed the existence of black holes 100 years after they were theorised by Albert Einstein’s theory of relativity and by astronomer Karl Schwarzschild.

Did ‘Interstellar’ get it right about Black Holes?

(THIS ARTICLE IS COURTESY OF THE SHANGHAI CHINA’S ‘SHINE’ NEWSPAPER)

 

Did ‘Interstellar’ get it right?

 Agencies

Reuters

A supermassive black hole with millions to billions times the mass of our sun is seen in an undated NASA artist’s concept illustration.

The world will finally get to see how a black hole looks like.

The first-ever close-up of a black hole — the spaces at the center of every large galaxy — can be seen by the public at 9pm Beijing time today when six simultaneous press conferences are held in Shanghai, Taipei, Brussels, Chile’s Santiago, Tokyo and Washington.

The picture will have been captured by the Event Horizon Telescope, a network of eight radio telescopes scattered across the globe, thus creating a giant virtual telescope with a diameter equaling that of the Earth.

The EHT allows astronomers to clearly see an orange on the Moon.

The project’s researchers obtained the first data in April 2017 from the global network of telescopes.

The telescopes that collected that initial data are located in the US states of Arizona and Hawaii as well as Mexico, Chile, Spain and Antarctica. Since then, telescopes in France and Greenland have been added to the network.

The telescopes were trained on two supermassive black holes in very different corners of the universe to collect data. Sagittarius A*, in a mass of 4 million suns, is located at the center of the Milky Way, and another, unnamed, is located at the center of the neighboring Virgo A galaxy, weighing 1,500 times of Sagittarius A*.

The picture to be unveiled today is likely to zoom in on one or the other. The data collected by the far-flung telescope array still had to be collected and collated.

“The imaging algorithms we developed fill the gaps of data we are missing in order to reconstruct a picture of a black hole,” the team said on its website.

The EHT project involves more than 200 astronomers from across the world, including those from China.

The research will put to the test a scientific pillar — physicist Albert Einstein’s theory of general relativity, according to University of Arizona astrophysicist Dimitrios Psaltis, project scientist for the EHT. That theory, put forward in 1915, was intended to explain the laws of gravity and their relation to other natural forces.

Black holes live up to their name. Basically, it is a place in space that swallows almost everything.

A black hole’s event horizon, one of the most violent places in the universe, is the point of no return beyond which anything — stars, planets, gas, dust, all forms of electromagnetic radiation including light — gets sucked in irretrievably.

For us, black holes are “dark stars.” So how do astronomers find black holes?

When black holes tear up nearby stars and swallow things in the space, they will emit great energy, generating bright light and massive radiation, through collision and friction.

That lead astronomers to the locations of black holes.

How do black holes look like?

No one knows, at least not until we discover it today.

AFP

Over the years, they have been depicted in many ways in the movies, but it is widely regarded that its image in the hit Hollywood movie “Interstellar” is the closest to the real thing.

Similar to the shape of Saturn, a star with rings, the black hole as depicted in “Interstellar” is very massive and rapidly spinning black with a glowing ring of matter encircling it.

The image was created after consultations with physicist and Nobel Laureate Kip Thorne of the California Institute of Technology.

Einstein’s theory, if correct, should allow for an extremely accurate prediction of the size and shape of a black hole.

“The shape of the shadow will be almost a perfect circle in Einstein’s theory,” Psaltis said. “If we find it to be different than what the theory predicts, then we go back to square one and we say, ‘Clearly, something is not exactly right.’”

Breakthrough observations in 2015 that earned the scientists involved a Nobel Prize used gravitational wave detectors to track two black holes smashing together.

As they merged, ripples in the curvatures of time-space created a unique, and detectable, signature.

“Einstein’s theory of general relativity says that this is exactly what should happen,” said Paul McNamara, an astrophysicist at the European Space Agency and an expert on black holes.

But those were tiny black holes — only 60 times more massive than the Sun — compared with either of the ones under the gaze of the EHT.

“Maybe the ones that are millions of times more massive are different — we just don’t know yet,” said McNamara.

How big is a black hole?

The diameter of a black hole depends on its mass but it is always double what we call the Schwarzschild radius. If the sun were to shrink to a singularity point, the Schwarzschild radius would be 3 kilometers and the diameter would be 6. For Earth, the diameter would be 18 millimeters, or about three quarters of an inch. The event horizon of the black hole at the center of the Milky Way, Sagittarius A*, measures about 24 million kilometers across.

What will the image look like?

The Event Horizon Telescope is not looking at the black hole per se, but the material it has captured. It won’t be a big disk in high resolution like in the Hollywood movie “Interstellar.” But we might see a black core with a bright ring — the accretion disk — around it. The light from behind the black hole gets bent like a lens. No matter what the orientation of the disk, you will see it as a ring because of the black hole’s strong gravity. Visually, it will look very much like an eclipse.

How is the image generated?

Rather than having one telescope that is 100 meters across, they have lots of telescopes with an effective diameter of 12,000km — the diameter of Earth. The data is recorded with very high accuracy, put onto hard disks, and shipped to a central location where the image is reconstructed digitally. This is very, very long baseline interferometry — over the entire surface of the Earth.

Dark Matter And Black Holes

(THIS ARTICLE IS COURTESY OF ‘WIRED’ NEWS)

 

WHEN IT COMES to the nature of dark matter, astronomers are still largely, well, in the dark. The existence of this mysterious substance was hypothesized more than 40 years ago to explain discrepancies between the calculations of how galaxies ought to behave, based on their mass, and what was actually observed. In short, it seemed like mass was missing. So Vera Rubin, the astronomer who first discovered this discrepancy, conjured an invisible substance that is far more abundant than “normal” matter and acts as the scaffolding for the large-scale structure of the universe. Today we call it dark matter.

Yet decades of hunting for the elusive dark matter particle still have not yielded direct evidence of its existence. Most cosmologists still believe that dark matter must exist, but some have splintered off to propose other explanations that explain away dark matter by modifying our understanding of gravity.

But two findings are now casting doubt on the modified gravity explanation. In March, a team of astronomers led by Yale professor Pieter van Dokkum and his graduate student Shany Danieli published two papers, one confirming the existence of a galaxy that appears to have almost no dark matter and the other announcing the discovery of a second galaxy of this type. The irony, the researchers say, is that the seeming lack of dark matter in these galaxies is strong evidence that it exists.

The reason they believe these galaxies have no dark matter is that their dynamics can be predicted using our traditional theories of gravity. The discrepancy of the “missing mass” that’s seen in most galaxies isn’t present here, meaning there’s no need for dark matter to explain their behavior. And it means that the modified version of gravity proposed by some cosmologists doesn’t predict these galaxies’ movements as cleanly as good old Newtonian physics.

The discovery of these dark-matter-free galaxies traces back to 2014, when van Dokkum and his colleagues finished building Dragonfly, a new kind of telescope, made of off-the-shelf telephoto camera lenses, that specializes in observing extremely faint celestial objects. Only a year after its first light, Dragonfly discovered a new galaxy characterized by an extreme lack of stars relative to its size. Known as an ultra-diffuse galaxy, this ghostly celestial object had roughly the same mass as our Milky Way, but only one hundredth of one percent of that mass could be attributed to “normal” matter like stars. In other words, van Dokkum and his colleagues had discovered a galaxy made of 99.99 percent dark matter.

While this galaxy was unique, its existence isn’t entirely surprising. Most cosmologists think that dense collections of dark matter act as a sort of seed for the formation of large celestial objects like galaxies. The general idea, says Anže Slosar, an astrophysicist at Brookhaven National Laboratory, is that once a collection of dark matter reaches a critical density, it collapses under its own gravity and forms a so-called “dark matter halo.” This halo, in turn, gravitationally attracts hydrogen gas to its center, where it begins to form stars and, eventually, galaxies. The mass of a dark matter halo varies from galaxy to galaxy, but it seemed like every galaxy must have at least some dark matter to keep its form. Indeed, this assumption was precisely what made Dragonfly’s next discovery so surprising.

In 2016, van Dokkum and his colleagues at Yale discovered NGC 1052-DF2, an ultra-diffuse galaxy that appeared to contain little to no dark matter at all. Last year, when the Yale astronomers published their results in the journal Nature, their peers in the cosmological community were incredulous. This was the first galaxy ever discovered that appeared to lack any dark matter, and as Carl Sagan rightly observed, “extraordinary claims require extraordinary evidence”—which is what many cosmologists thought the Yale team was missing.

University of Pennsylvania astrophysicist Robyn Sanderson says the skepticism about DF2 sprang mostly from the limited amount of data used to draw the conclusion. In this case, the Yale team was using data from just 10 star clusters observed over a period of two nights. This meant it was possible they were overlooking key details of the star clusters’ motion, which would distort their estimations of the galaxy’s mass—and undermine their claim that it lacked dark matter.

The Yale researchers recognized this possible source of error themselves when they published their paper on DF2. The only way to resolve this conundrum was to make more detailed measurements or to find another galaxy with characteristics similar to DF2. In March, the Yale team published two papers that did exactly these things.

The first paper offered more refined measurements of stellar velocities within DF2. This time, rather than just measuring the velocities of 10 star clusters, van Dokkum and Danieli used the Keck telescope in Hawaii to observe the velocities of the stars within the star clusters. This approach produced far more data that reinforced the team’s earlier conclusion that the galaxy lacked dark matter.

The other paper announced the discovery of a second galaxy, DF4, which also appears to have little, if any, dark matter. Not only does this increase the odds that the DF2 observations are accurate, it also means such ultra-diffuse galaxies might not be so rare. The fact that two were found in quick succession, Danieli says, was “really reassuring.” Nevertheless, she says “it’s still too early to say whether they are super rare or quite common.” The team will begin observing other nearby ultra-diffuse galaxies next month in an effort to answer this question.

But that won’t resolve the mystery of how these strange galaxies came to exist in the first place. Theoretical cosmologists will have to run simulations to determine how a galaxy can lose its dark matter, she says. One leading theory involves tidal interactions, which is astronomer-speak for when the gravitational forces of two neighboring galaxies pull material from each galaxy and distort them. DF2 and DF4 are both near the galaxy NGC 1052, which makes it a strong candidate for the galaxy that stole their dark matter.

However they came to be, Danieli argues that the existence of these galaxies is a blow to the modified gravityexplanation for why most galaxies don’t behave as we’d expect.

Known as modified Newtonian dynamics, or MOND, this theory recasts gravity such that it has different effects at the galactic scale. Although MOND has successfully predicted the stellar dynamics of hundreds of galaxies, most of which are relatively isolated, it must be able to predict the dynamics of all galaxies to dethrone dark matter as the going cosmological theory.

As Slosar explains it, the discovery of DF2 and DF4 strengthens the case for the existence of a dark matter particle because it means that it can be separated from normal matter. Because these galaxies behave in line with standard gravitational theory, using the equations discovered by Newton and Kepler, they present a challenge to MOND.

“If you find galaxies, some of which have a lot of dark matter and some of which have a little dark matter, you can’t explain it with the loss of gravity unless you’re willing to say that one part of the universe has a different law of gravity than another part, which is just silly,” Slosar says. “The entire point of physics is to find unified laws that are always there. This is why it is an argument for the existence of dark matter.”

So does the existence of galaxies devoid of dark matter pose an existential threat for MOND? Stacy McGaugh, an astronomer at Case Western Reserve University, doesn’t think so. “When DF2 was first discovered, it was portrayed as a huge problem for MOND,” McGaugh says. “On more careful analysis, it turned out that the prediction of MOND was spot-on what was observed.”

The analysis by McGaugh and his colleagues of DF2’s implications for MOND hinges on the galaxy’s proximity to the massive elliptical galaxy NGC1052. Under a set of “reasonable” assumptions, paired with equations from MOND, McGaugh and his colleagues found that NGC1052’s gravitational effects on DF2 would return stellar velocities similar to what van Dokkum and Danieli actually observed. Although he hasn’t had the chance to repeat this analysis for DF4, McGaugh says it also “appears to be consistent with MOND, since it is likely affected by NGC 1052.”

The existence of these galaxies poses a number of vexing problems for the theory of galactic formation, which must account for how a galaxy can come to be violently stripped of its dark matter and still retain the relative order seen, for example, in the presence of star clusters in DF2 and DF4. Will further observations of ultra-diffuse galaxies resolve the dark matter debate? Probably not, but they will, at least, shed some light on the matter.


More Great WIRED Stories

Gargantuan ‘X-ray Chimneys’ in the Center of Our Galaxy

(THIS ARTICLE IS COURTESY OF ‘EXTREME TECH)

 

Astronomers Spot Gargantuan ‘X-ray Chimneys’ in the Center of Our Galaxy

The monster black hole that anchors our galaxy is safely 28,000 light years away from Earth. That’s a good thing, too. The region around that back hole is overflowing with dangerous radiation and fragmented stars. Astronomers observing the center of the Milky Way have spotted some unusual features that drive home just how violent the area is. The galaxy sports a pair of gargantuan “X-ray chimneys” that expel the matter and energy building up around the black hole.

UCLA professor of astronomy and astrophysics Mark Morris, who contributed to the research, likens the features to exhaust vents, bleeding off energy from the galaxy in the form of X-rays. The international team looked to the black hole, known as Sagittarius A* (pronounced “Sagittarius A Star”) in an effort to learn more about star formation in the Milky Way. All galaxies foster the development of stars, but the rate of new star formation can vary wildly. The fate of the matter and energy spiraling toward a galaxy’s central black hole can be a significant factor in star formation.

To track the material blasted out around Sagittarius A*, the researchers turned to the European Space Agency’s XMM-Newton satellite. This X-ray observatory launched almost 20 years ago, but it’s still going strong. The team used data from 2012, as well as 2016 to 2018 to see what the black hole was doing with all the stars getting smashed to bits in its general vicinity.

According to the researchers, Sagittarius A* produces “chimneys” of X-ray that extend north and south from the disk of the galaxy. The structures are more appropriately known as Fermi bubbles, massive cavities carved out of the gas cloud surrounding the galaxy. The north and south chimney both start within 160 light years of the black hole, extending outward about 25,000 light years. That’s almost the distance from Sagittarius A* to Earth.

The black hole in our galaxy is about 4 million times the size of the sun, but other galaxies have central black holes that are much larger. We can study the Milky Way close up, which could provide insights into how these more energetic galaxies work. Understanding how energy moves through the chimneys and into surrounding space could help explain why some regions become rich in star formation, and others are relatively barren.

Astronomers Have Detected 83 Black Holes in The Early Universe

(THIS ARTICLE IS COURTESY OF SCIENCEALERT.COM)

 

Astronomers Have Detected 83 Black Holes in The Early Universe, Challenging Cosmology

MICHELLE STARR
19 MAR 2019

Astronomers have just found 83 quasars, powered by supermassive black holes and dating back to the infancy of the Universe, when it was less than 10 percent of its current age.

This discovery reveals that such objects were more common at the dawn of time than we thought, and challenges our entire cosmological model.

Quasars are among the brightest objects in the Universe, extremely luminous galactic cores powered by actively feeding supermassive black holes. As material swirls around the black hole, its friction generates such intense radiation that it can be seen, even from billions of light-years away.

There’s just one big problem. We think we know how black holes form – they are the collapsed cores of massive stars. And supermassive black holes can have up to billions of times the mass of the Sun.

This takes time, and requires copious amounts of matter. So how the heck did all these quasars pop up so early in the Universe’s history?

“It is remarkable that such massive dense objects were able to form so soon after the Big Bang,” said astrophysicist Michael Strauss of Princeton University.

“Understanding how black holes can form in the early Universe, and just how common they are, is a challenge for our cosmological models.”

old quasarA quasar 13.05 billion light-years away. (National Astronomical Observatory of Japan)

We’ve known there were quasars hanging out back then. The oldest one we’ve seen dates back to around 690 million years after the Big Bang, when the Universe was around five percent of its current age – and a few others have been spotted too.

But these – although still a puzzle – were thought to be relatively rare. So astronomers from Japan, Taiwan and the US broadened the search, using data from the Hyper Suprime-Cam mounted on the Subaru Telescope in Hawaii.

With this instrument, they could look for much fainter quasars than ones discovered previously. The oldest quasar they found was a massive 13.05 billion light-years away, tying for the second-most distant quasar ever found.

The Universe is thought to be about 13.8 billion years old, and the first stars – we think – didn’t appear until around 500 million years after the Big Bang, after the neutral hydrogen of the early-early Universe was reionised. That just leaves a couple of hundred million years for the quasars to form.

The team’s survey suggests that these objects were actually fairly abundant back then. They identified candidate quasars in the HSC data, then conducted a dedicated survey using multiple telescopes to obtain light signatures, or spectra, from these objects.

smbh quasars(National Astronomical Observatory of Japan)

These spectra turned up the 83 new quasars, over the last few years. Together with 17 previously known quasars in the survey region, the team calculated that there’s roughly one quasar for every cubic giga-light-year; that is, cube of space with a billion light-years per side.

While that’s more than previously thought, it’s not quite enough for another hypothesis.

Just after the Big Bang, the Universe was a sort of dark, hot “primordial soup” on a cosmic scale, rapidly expanding.

As it expanded, it cooled, causing protons and neutrons to start to combine into ionised hydrogen atoms; around 240,000-300,000 years after the Big Bang, these hydrogen atoms attracted electrons, coalescing into neutral hydrogen.

But it wasn’t until gravity started to pull together the first stars and galaxies in this murky, hydrogen-filled void that starlight appeared… and not long after that, according to current theories, the neutral hydrogen was excited by the ultraviolet light of these newborn stars, galaxies, as-yet undetected quasars, or a combination of all three.

This is called the Epoch of Reionisation, and we just don’t know how it happened. But now we know – based on this research – there weren’t enough quasars to be solely responsible for this process.

The new quasar population data will help us learn more about the formation of supermassive black holes in the early Universe – and the team is going to continue the search to see if they can find quasars that are even older. This could help researchers to figure out when the first black holes were born.

“The quasars we discovered will be an interesting subject for further follow-up observations with current and future facilities,” said astronomer Yoshiki Matsuoka of Ehime University in Japan.

“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 discoveries have been detailed in five papers, which can be found herehereherehere and here.

Magnetic fields may be the key to black hole activity

(THIS ARTICLE IS COURTESY OF PHYS.ORG AND NASA)

 

Magnetic fields may be the key to black hole activity

October 17, 2018, NASA
Magnetic fields may be the key to black hole activity
Artist’s conception of the core of Cygnus A, including the dusty donut-shaped surroundings, called a torus, and jets launching from its center. Magnetic fields are illustrated trapping the dust in the torus. These magnetic fields could be …more

Collimated jets provide astronomers with some of the most powerful evidence that a supermassive black hole lurks in the heart of most galaxies. Some of these black holes appear to be active, gobbling up material from their surroundings and launching jets at ultra-high speeds, while others are quiescent, even dormant. Why are some black holes feasting and others starving? Recent observations from the Stratospheric Observatory for Infrared Astronomy, or SOFIA, are shedding light on this question.

SOFIA data indicate that magnetic fields are trapping and confining dust near the center of the active galaxy, Cygnus A, and feeding material onto the supermassive black hole at its center.

The , which attempts to explain the different properties of active galaxies, states that the core is surrounded by a donut-shaped dust cloud, called a torus. How this obscuring structure is created and sustained has never been clear, but these new results from SOFIA indicate that magnetic fields may be responsible for keeping the dust close enough to be devoured by the hungry black hole. In fact, one of the fundamental differences between active galaxies like Cygnus A and their less active cousins, like our own Milky Way, may be the presence or absence of a  around the black hole.

Although celestial magnetic fields are notoriously difficult to observe, astronomers have used polarized light—optical light from scattering and radio light from accelerating electrons—to study magnetic fields in galaxies. But optical wavelengths are too short and the radio wavelengths are too long to observe the torus directly. The infrared wavelengths observed by SOFIA are just right, allowing scientists, for the first time, to target and isolate the dusty torus.

Magnetic fields may be the key to black hole activity
Two images of Cygnus A layered over each other to show the galaxy’s jets glowing with radio radiation (shown in red). Quiescent galaxies, like our own Milky Way, do not have jets like this, which may be related to magnetic fields. The …more

SOFIA’s new instrument, the High-resolution Airborne Wideband Camera-plus (HAWC+), is especially sensitive to the infrared emission from aligned dust grains. This has proven to be a powerful technique to study magnetic fields and test a fundamental prediction of the unified model: the role of the dusty torus in the active-galaxy phenomena.

“It’s always exciting to discover something completely new,” noted Enrique Lopez-Rodriguez, a scientist at the SOFIA Science Center, and the lead author on the report of this new discovery. “These observations from HAWC+ are unique. They show us how infrared polarization can contribute to the study of galaxies.”

Recent observations of the heart of Cygnus A made with HAWC+ show infrared radiation dominated by a well-aligned dusty structure. Combining these results with archival data from the Herschel Space Observatory, the Hubble Space Telescope and the Gran Telescopio Canarias, the research team found that this powerful active galaxy, with its iconic large-scale jets, is able to confine the obscuring torus that feeds the supermassive black hole using a strong .

The results of this study were published in the July 10th issue of The Astrophysical Journal Letters.

Cygnus A is in the perfect location to learn about the role magnetic fields play in confining the dusty torus and channeling material onto the supermassive black hole because it is the closest and most powerful active galaxy. More observations of different types of galaxies are necessary to get the full picture of how magnetic fields affect the evolution of the environment surrounding . If, for example, HAWC+ reveals highly polarized  from the centers of active galaxies but not from quiescent , it would support the idea that magnetic fields regulate black hole feeding and reinforce astronomers’ confidence in the unified model of .

 Explore further: Black holes play hide-and-seek in low-luminosity radio galaxies

More information: Enrique Lopez-Rodriguez et al. The Highly Polarized Dusty Emission Core of Cygnus A, The Astrophysical Journal (2018). DOI: 10.3847/2041-8213/aacff5

Read more at: https://phys.org/news/2018-10-magnetic-fields-key-black-hole.html#jCp

New Evidence That Supermassive Black Holes Eventually Suck the Life out of Big Galaxies

(THIS ARTICLE IS COURTESY OF GIZOMDO)

 

New Evidence That Supermassive Black Holes Eventually Suck the Life out of Big Galaxies

The Centaurus A galaxy, showing the characteristic jets of gas thrown off by a supermassive black hole. (Image: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray))

At the core of each large galaxy lies a supermassive black hole with the mass of 1 million suns. New research shows that these celestial vacuum cleaners do more than just devour nearby objects—they also grow to a size that eventually suppresses a galaxy’s ability to churn out new stars, effectively rendering them sterile.

Young galaxies are absolutely bursting with bright, newly formed stars. As time passes, however, star formation eventually grinds to a halt. A new study published in Nature shows that supermassive black holes play a critical role in determining when large galaxies stop producing new stars, a process known as “quenching.”

Stars form out of cold gas, so when a galaxy runs out of cold gas it’s effectively quenched. One possible way this could happen—at least for galaxies with supermassive black holes—is that the gas that pours onto a supermassive black hole triggers the production of high-energy jets. The energy released by these jets can expel cold gas out of the galaxy, causing star formation to shut down.

At least that’s the theory. This idea has been around for quite some time, but no observational evidence existed to support the alleged correlation between supermassive black holes and star formation. The new study, led by Ignacio Martín-Navarro from the University of California Santa Cruz, now fills this gap in our knowledge.

Using data collected by the Hobby-Eberly Telescope Massive Galaxy Survey, Martín-Navarro’s team analyzed the spectra of light coming from distant galaxies. This allowed them to separate and measure the varying wavelengths of light coming from these distant objects. The scientists used this data to create a historical snapshot of a galaxy’s star formation history. They then compared this history with black holes of different masses, which resulted in some striking differences—differences that correlated with black hole mass, but not the shape, size, or other properties of black holes.

“The subsequent quenching of star formation takes place earlier and more efficiently in galaxies that host higher-mass central black holes,” wrote the researchers. “The observed relation between black-hole mass and star formation efficiency applies to all generations of stars formed throughout the life of a galaxy, revealing a continuous interplay between black-hole activity and… cooling.”

As Martín-Navarro clarified in an accompanying statement, for galaxies with the same mass of stars, but with a different black hole mass in the center, “those galaxies with bigger black holes were quenched earlier and faster than those with smaller black holes.” This means that star formation will last longer in galaxies with smaller central black holes. “[…Accretion onto more massive black holes leads to more energetic feedback from active galactic nuclei, which would quench star formation faster,” he said.

It’s an exciting result, but there’s still lots of work to do. While the researchers managed to produce observational evidence showing that black hole mass can be connected to the quenching of star formation, they’re still unclear about the exact mechanical processes involved. As study co-author Aaron Romanowsky explained, “There are different ways a black hole can put energy out into the galaxy, and theorists have all kinds of ideas about how quenching happens, but there’s more work to be done to fit these new observations into the models.”

Our galaxy, the Milky Way, features its own super massive black hole and is not immune to this process. It is currently transitioning from star-forming mode to a passive, sterile existence. Eventually, a few billion years from now, all the stars in the Milky Way will be extinguished, and the super massive black hole at center will evaporate into nothing. It’s a grim prospect, but such is the way of the indifferent cosmos.

Eight planets found orbiting distant star, NASA says

(THIS ARTICLE IS COURTESY OF CNN AND NASA)

 

Eight planets found orbiting distant star, NASA says

The galaxy explained

Story highlights

  • For the first time, eight planets have been found orbiting Kepler-90
  • It is tied with our solar system for a star hosting the most known planets

(CNN) For the first time, eight planets have been found orbiting a distant star, Kepler-90, 2,545 light-years from Earth in the Draco constellation, NASA announced Thursday. It is the first star known to support as many planets as are orbiting our own sun, and researchers believe that this is the first of many to come.

Researchers had known that seven planets were orbiting the star. But Google Artificial Intelligence — which enables computers to “learn” — looked at archival data obtained by NASA’s planet-hunting Kepler telescope and uncovered the eighth planet.
With the idea of eventually differentiating among exoplanets, Christopher Shallue, senior software engineer at Google AI in California, and Andrew Vanderburg, astronomer and NASA Sagan postdoctoral fellow at the University of Texas, Austin, trained a computer how to differentiate between images of cats and dogs.
They refined their approach to identify exoplanets in Kepler data based on the change in light when a planet passed in front of its star. The neural network learned to identify these by using signals that had been vetted and confirmed in Kepler’s planet catalog. Ninety-six percent of the time, it was accurate.
Since launching in 2009, Kepler has watched more than 150,000 stars in one part of the sky to determine exoplanet candidates, based on the slight dimming of stars as potential planets pass across them. Kepler gathered a dataset of 35,000 possible signals indicating planets. In order to help find weaker signals of potential planets that researchers had missed, the neural network was trained to look for weak signals in star systems that were known to support multiple planets.
close dialog
Tell us where to send you Five Things
Morning briefings of all the news & buzz people will be talking about
Activate Five Things
By subscribing you agree to our
privacy policy.
“Machine learning really shines in situations where there is so much data that humans can’t search it for themselves,” Shallue said.
The new planet has been dubbed Kepler-90i. It’s not a hospitable environment. It’s small, “sizzling” hot and rocky, whirling around its star every 14.4 days. In our solar system, the closest planet to the sun, Mercury, has an orbit of 88 days.
“The Kepler-90 star system is like a mini version of our solar system. You have small planets inside and big planets outside, but everything is scrunched in much closer,” Vanderburg said.
Although Kepler-90 is a sun-like star, the planets are all bunched together in tight orbits around it — the same distance that Earth is from the sun.

“Just as we expected, there are exciting discoveries lurking in our archived Kepler data, waiting for the right tool or technology to unearth them,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington. “This finding shows that our data will be a treasure trove available to innovative researchers for years to come.”
Researchers also announced that they had uncovered a sixth planet in the Kepler-80 system, Kepler-80g, which is similar in size to Earth. It also has an orbit of 14.4 days. The star is cooler and redder than our sun, and all of the planets orbit very tightly around it. Five of the six planets form a resonant chain, in which they are locked in orbit by mutual gravity. The Kepler-80 system is stable, as the previously discovered seven-planet TRAPPIST-1 system has proven to be.
To date, Kepler has observed 2,525 confirmed exoplanets.
“These results demonstrate the enduring value of Kepler’s mission,” said Jessie Dotson, Kepler’s project scientist at NASA’s Ames Research Center in California. “New ways of looking at the data — such as this early-stage research to apply machine learning algorithms — promises to continue to yield significant advances in our understanding of planetary systems around other stars. I’m sure there are more firsts in the data waiting for people to find them.”
Missions launching in 2018, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will enable further and closer study of planet candidates identified by Kepler.
Compared with Kepler, TESS will use a similar transit method for observing planets when they pass in front of their parent stars. Though Kepler looked at one portion of the sky for stars that were farther away for a longer time, TESS will observe the entire sky and focus on the brightest and closest stars, each for 30 days.
The James Webb Space Telescope is capable of observing large exoplanets and detecting starlight filtered through their atmospheres, which will enable scientists to determine the atmospheric composition and analyze them for gases that can create a biological ecosystem.
The K2 mission, which launched in 2014, is extending Kepler’s legacy to new parts of the sky and new fields of study, adding to NASA’s “arc of discovery.” It has enough fuel to keep identifying candidates until summer 2018. It’s helping bridge the gap between Kepler and TESS as far as identifying targets for the James Webb Space Telescope to observe.
  

Astronomers just discovered a super massive black hole from the dawn of the universe

(THIS ARTICLE IS COURTESY OF POPULAR SCIENCE)

 

Astronomers just discovered a supermassive black hole from the dawn of the universe

And it’s much bigger than we expected.

black hole and quasar

An artist’s image of a black hole with an accretion disk and a quasar shooting away from it.

Robin Dienel, courtesy of the Carnegie Institution for Science

There was a bang. A big one. It was the beginning of everything, but for several hundred million years, all was darkness. Then, lights started flickering to life, stars and gases and galaxies all coming online.

One of the brightest lights during that dawn had a dark and hungry hole at its heart. More massive than 800 million suns, the black hole existed just 690 million years after the Big Bang, when the universe was still an infant.


Article Continues Below:

How Does A Dyson Swarm Work?

By the year 3100, Earth’s skyrocketing population will need a lot of… 

Researchers, including Eduardo Bañados, reported the existence of the black hole and its accompanying bright quasar in a paper in Nature this week. The astronomers were looking for evidence of black holes in these early days of the universe, but they were still surprised at the sheer size of this one, named J1342+0928.

Black holes are points in the universe where gravity is so intense that nothing can escape. Not rocks, not gas, not even light. Near large black holes, surrounding material swirls around to form something called an accretion disk. Material in the disk spins at thousands of miles per second, heating up as it moves and slams into other bits of dusts and gas, all riding the same frantic carousel toward doom.

The material itself spins down into the black hole, never to be seen again, but its jostling releases energy that heads out into the universe in the form of immensely bright heat and light. That light made the quasar that Bañados and his co-authors were able to detect, which they used to estimate J1342+0928’s surprising mass.

Bañados says that a typical black hole, forming as a star collapses, might have the mass of 50 to 100 suns. “If you make it grow, feed it material like gas from its surroundings and let it grow for 690 million years, you wouldn’t be able to reach the size of this supermassive black hole,” Bañados says.

To figure out how this black hole could have gotten so large so quickly, observational astronomers like Bañados must team up with theoretical astronomers and astrophysicists. In the process, they’re also looking into ever-so-slightly broader questions, like the evolution of everything. “This object is so distant and so luminous that it provides a laboratory to study the early universe,” Bañados says.

Bañados has discovered about half of the most distant quasars on record, but this one—while not the most massive—is the furthest of them all. Because light takes time to travel, the more distant an object is, the earlier back in history we’re peering when we look at it. So this object comes from earlier in the universe’s lifespan than any of the others scientists have observed.

“This record is nice, but we’re not doing this for the record,” Bañados says. “This is so mature that I would be very surprised if this is the first quasar ever formed. I hope we or someone else will break this record soon.”

This particular quasar is so bright that it outshines the galaxy where it’s located—it’s 1000 times more luminous. And it’s not like that galaxy is a slouch either, even though the quasar at its heart drowns it out in both the optical and ultraviolet wavelengths of light. Fortunately, if you look at the galaxy in longer wavelengths, you can start to see some details. Bañados is a co-author on another paper that came out this week in The Astrophysical Journal Letters that focuses on the galaxy around the black hole. They the galaxy was positively choked with interstellar dust, producing somewhere around 100 new solar masses (the mass of our star) per year. Our galaxy only makes about one solar mass per year.

They were also able to detect something about the neighborhood of space around the black hole, finding that about half of the area had un-ionized hydrogen (which would have blocked out light, leading to those first few hundreds of millions of years of darkness in the universe) and half had ionized hydrogen, indicating that this black hole could have existed at the time when the universe switched from being dominated by the former to the latter.

“How this happened and when this happened have fundamental implications for the evolution of the universe later on,” Bañados says. “But we need to find and keep searching for more objects even further away and try to repeat that experiment.”

Luckily, there are now more opportunities to look into those universal origins. In 2018, Bañados and other researchers around the world will use a variety of telescopes to explore this object more thoroughly and look for others in the night sky.

“We’re a very fortunate generation,” Bañados says. “We’re the first human beings to have the technology to study and characterize in detail some of the first galaxies and black holes that formed in the universe. If that’s not fascinating, I don’t know what is.”

MYMonkey MIND

Your Brain is a Radio that Does What its Told

THE WORLD BEYOND YOU (TWBY)

ALWAYS CURIOUS AND AHEAD

Inspire Art

“The purpose of art is washing the dust of daily life off our souls” - Pablo Picasso

Scuba Hank NYC

Scuba Diving Around The World

Everything about underwater and sky

underwater, diving, flying, drone, photo, umi, sora, 海, 空

Extra Life

Independent opinions on video games and films

IVCFilterLitigation.info

HAVE YOU SUFFERED A SERIOUS INJURY FROM AN IVC FILTER?

Mimis Organic

Be Natural, Organic and beautiful

Wellness & Beauty Marketing

Isagenix and Avon blog - USA

%d bloggers like this: