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Study Reveals Six Galaxies Undergoing Sudden, Dramatic Transitions

Galaxies come in a wide variety of shapes, sizes and brightnesses, ranging from humdrum ordinary galaxies to luminous active galaxies. While an ordinary galaxy is visible mainly because of the light from its stars, an active galaxy shines brightest at its center, or nucleus, where a supermassive black hole emits a steady blast of bright light as it voraciously consumes nearby gas and dust.

Sitting somewhere on the spectrum between ordinary and active galaxies is another class, known as low-ionization nuclear emission-line region (LINER) galaxies. While LINERs are relatively common, accounting for roughly one-third of all nearby galaxies, astronomers have fiercely debated the main source of light emission from LINERs. Some argue that weakly active galactic nuclei are responsible, while others maintain that star-forming regions outside the galactic nucleus produce the most light.

A team of astronomers observed six mild-mannered LINER galaxies suddenly and surprisingly transforming into ravenous quasars–home to the brightest of all active galactic nuclei. The team reported their observations, which could help demystify the nature of both LINERs and quasars while answering some burning questions about galactic evolution, in the Astrophysical Journal on September 18, 2019. Based on their analysis, the researchers suggest they have discovered an entirely new type of black hole activity at the centers of these six LINER galaxies.

“For one of the six objects, we first thought we had observed a tidal disruption event, which happens when a star passes too close to a supermassive black hole and gets shredded,” said Sara Frederick, a graduate student in the University of Maryland Department of Astronomy and the lead author of the research paper. “But we later found it was a previously dormant black hole undergoing a transition that astronomers call a ‘changing look,’ resulting in a bright quasar. Observing six of these transitions, all in relatively quiet LINER galaxies, suggests that we’ve identified a totally new class of active galactic nucleus.”

All six of the surprising transitions were observed during the first nine months of the Zwicky Transient Facility (ZTF), an automated sky survey project based at Caltech’s Palomar Observatory near San Diego, California, which began observations in March 2018. UMD is a partner in the ZTF effort, facilitated by the Joint Space-Science Institute (JSI), a partnership between UMD and NASA’s Goddard Space Flight Center.

Changing look transitions have been documented in other galaxies–most commonly in a class of active galaxies known as Seyfert galaxies. By definition, Seyfert galaxies all have a bright, active galactic nucleus, but Type 1 and Type 2 Seyfert galaxies differ in the amount of light they emit at specific wavelengths. According to Frederick, many astronomers suspect that the difference results from the angle at which astronomers view the galaxies.

Type 1 Seyfert galaxies are thought to face Earth head-on, giving an unobstructed view of their nuclei, while Type 2 Seyfert galaxies are tilted at an oblique angle, such that their nuclei are partially obscured by a donut-shaped ring of dense, dusty gas clouds. Thus, changing look transitions between these two classes present a puzzle for astronomers, since a galaxy’s orientation towards Earth is not expected to change.

Frederick and her colleagues’ new observations may call these assumptions into question.

© R. Buta (University of Alabama/Image enhancement: Jean-Baptiste Faur Spiral Seyfert Galaxy NGC 3081: Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.

© R. Buta (University of Alabama/Image enhancement: Jean-Baptiste Faur
Spiral Seyfert Galaxy NGC 3081: Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.

“We started out trying to understand changing look transformations in Seyfert galaxies. But instead, we found a whole new class of active galactic nucleus capable of transforming a wimpy galaxy to a luminous quasar,” said Suvi Gezari, an associate professor of astronomy at UMD, a co-director of JSI and a co-author of the research paper. “Theory suggests that a quasar should take thousands of years to turn on, but these observations suggest that it can happen very quickly. It tells us that the theory is all wrong. We thought that Seyfert transformation was the major puzzle. But now we have a bigger issue to solve.”

Frederick and her colleagues want to understand how a previously quiet galaxy with a calm nucleus can suddenly transition to a bright beacon of galactic radiation. To learn more, they performed follow-up observations on the objects with the Discovery Channel Telescope, which is operated by the Lowell Observatory in partnership with UMD, Boston University, the University of Toledo and Northern Arizona University. These observations helped to clarify aspects of the transitions, including how the rapidly transforming galactic nuclei interacted with their host galaxies.

“Our findings confirm that LINERs can, in fact, host active supermassive black holes at their centers,” Frederick said. “But these six transitions were so sudden and dramatic, it tells us that there is something altogether different going on in these galaxies. We want to know how such massive amounts of gas and dust can suddenly start falling into a black hole. Because we caught these transitions in the act, it opens up a lot of opportunities to compare what the nuclei looked like before and after the transformation.”

Unlike most quasars, which light up the surrounding clouds of gas and dust far beyond the galactic nucleus, the researchers found that only the gas and dust closest to the nucleus had been turned on. Frederick, Gezari and their collaborators suspect that this activity gradually spreads from the galactic nucleus–and may provide the opportunity to map the development of a newborn quasar.

“It’s surprising that any galaxy can change its look on human time scales. These changes are taking place much more quickly than we can explain with current quasar theory,” Frederick said. “It will take some work to understand what can disrupt a galaxy’s accretion structure and cause these changes on such short order. The forces at play must be very extreme and very dramatic.”

In addition to Frederick and Gezari, UMD-affiliated co-authors of the research paper include Adjunct Associate Professor of Astronomy Bradley Cenko, former Neil Gehrels Prize Postdoctoral Fellow Erin Kara and astronomy graduate student Charlotte Ward.

More information: Sara Frederick et al, A New Class of Changing-look LINERs, The Astrophysical Journal (2019). DOI: 10.3847/1538-4357/ab3a38

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Headline Image: © (Left; infrared & visible light imagery): ESA/Hubble, NASA and S. Smartt (Queen’s University Belfast); (Right; artist’s concept): NASA/JPL-Caltech

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Dinosaurs came from across the galaxy, NASA demonstrates with incredible video

NASA, through a very well explained video, shows us that the dinosaurs originated from the other side of galaxy.

Dinosaurs lived on the other side of the galaxy, NASA demonstrates
Did you know that dinosaurs lived on the other side of the galaxy?

NASA is the largest space studies and research entity in the world. Yes it is. They are not the only ones who study everything related to outer space. That’s why when NASA talks about space dinosaurs, we all pay attention, especially when there’s a video.

NASA takes seriously the fact that dinosaurs may have originated elsewhere in the galaxy. This sounds crazy, so you have to watch a video where everything is explained.

The video was posted by Dr. Jessie Christiansen in her Twitter account. She is a NASA researcher and the publication is as you will see below.

She says:

I was always interested in galactic archeology, but I don’t think that’s what they meant.

The sun takes about 200 million years to orbit the center of the galaxy, which means that the last time we were there occurred at the beginning of the Jurassic period. The dinosaurs walked the land and the sea.

The Jurassic period lasted 55 million years.

The Cretaceous period ranged from 145 to 66 million ago. The middle Cretaceous occurred on the other side of the galaxy.

65 million years ago, extinction occurred.

The rise of mammals has lasted 65 million years to the present.

The sun takes about 200 million years to orbit the center of the galaxy.

What will Earth look like on the next galactic anniversary? While not as exciting as seeing invading dinosaurs, at least it leaves us with a good question. And perhaps until then, the human is not even a memory on the surface of the earth.

Christiansen said it took her about four hours to make the film using timed animations in PowerPoint. She also noted a couple of minor corrections to the text in her video: Plesiosaurs are not dinosaurs, and we complete a galactic orbit every 250 million years, not 200 million years.

‘A spiral through space’

But galactic movement is more complicated than the video shows. The other stars and planetary systems in the galaxy are also moving, at different speeds and in different orbits. The inner portions spin faster than the outer regions.

What’s more, the galaxy itself is moving through space, slowly approaching the nearby Andromeda galaxy.

“The animation kind of makes it seem like we’ve come back to the same spot, but in reality the whole galaxy has moved a very long way,” Christiansen said. “It’s more like we’re doing a spiral through space. As the whole galaxy’s moving and we’re rotating around the center, it kind of creates this spiral.”

milky way galaxy center spitzer infrared
The center of our Milky Way galaxy, imaged by the Spitzer Space Telescope’s infrared cameras. 
NASA, JPL-Caltech, Susan Stolovy (SSC/Caltech) et al.

So in the solar system’s rotation around the galactic center, we’re not returning to a fixed point. The neighborhood is different from the last time we were here.

Earth, however, is not drastically different; it still supports complex life. That’s partially thanks to the path of our sun’s galactic orbit.

“Our solar system doesn’t travel to the center of the galaxy and then back again,” Christiansen said. “We always stay about this distance away.”

In other words, even as our solar system travels through the Milky Way, it doesn’t approach the inhospitable center, where life probably wouldn’t survive.

“There’s a lot of stars, it’s dynamically unstable, there’s a lot of radiation,” Christiansen said. “Our solar system certainly doesn’t pass through that.”

That’s a huge part of why dinosaurs, mammals, or any other form of life can exist on Earth.

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NASA Supercomputer Creates Millions of Virtual ‘Universes’ to Reveal Mystery of Cosmos

Astronomers have historically turned to two disparate methods to understand the Universe. Telescopes have traditionally been used to observe galaxies, while scientists have recently attempted to simulate them on large computers. Now a theoretical astrophysicist has revealed the early results of “a third way” – a novel method offering new insights into galaxy formation and the role dark matter plays in it.

Professor Peter Behroozi of Arizona University is leading a team harnessing NASA’s Pleiades supercomputer to generate millions of Universe simulations, each following a different theory of galaxy formation.

He told Express.co.uk: “Telescopes can see lots of galaxies in exquisite detail but they are only tiny snapshots of their histories.

“Galaxies take hundreds of millions of years to evolve and of course, during a human lifetime, we can’t even see a tiny fraction of that, so can’t tell how does they evolved with observations alone.

“Simulators are inputting all the physics they knew into very big computers still experience issues, because even computers for the next few hundred years will be insufficient to simulate a galaxy down to its individual components.”

Instruments like NASA’s Hubble Space Telescope can see both galaxies as they were many billions of years ago and nearby galaxies, obtaining exquisite images of how they look today.

The scientist uses the metaphor of having pictures of people at all different time points in the history of their lives.

The problem scientists face is piecing together how galaxies grow through time.

He said:

“We put a guess into a computer for how quickly galaxies grow over time and how many mergers they have and we generate an entire Universe full of galaxies, going from the very first time points right after the Big Bang until the present day.

“And then still inside the computer, we pretend we’re astronomers, and we observe this universe exactly as people have done here on earth.

“And we ask, do the observations in the computer resemble the observations of the real universe, or do they differ in some way?

“Things that we look at, for instance, include how many galaxies we see at different points in the history of the universe?

“How large are they? How clustered are they?

“And by asking the question ‘does the universe that we generated on the computer resemble the real universe?’ we can then get a sense of how close we are to the real answer.

“So it’s like a game of almost how to call you’re getting warmer or cooler, in terms of how close you are to what the real universe is doing.”

The Arizona University team’s simulations have already achieved some “surprising” results, showing how star formation may have been more efficient in the early Universe.

For context, most of stars in the Universe are in galaxies that stop forming new stars.

Professor Behroozi said:

“This has been a puzzle for a very long time, because if we observe these galaxies that have stopped forming stars, we find there’s a lot of material and lot of fuel available to form stars, but the galaxies are not using up this fuel to form new stars.

“What we found with the universe machine is the most common explanation, that is it was hard for the fuel to cool and condense to small enough regions to form stars, we found that was very less likely to be correct, because it gave a different prediction for how galaxies grew, than what came out of our measurements.”

The NASA universe machine – the size of entire floor of the building – took required around 5 million Central Processing Units (CPU) hours, meaning it would take a laptop 5 million hours to complete.

To convert that into something more familiar like years, that would be about half a millennium.

The resulting incredible simulations, as seen in the video above, are only the start, Professor Behroozi revealed.

He said:
“What we’ve done so far with galaxies, we want you to eventually include every part of the universe.

“In other words, to make a full, complete movie of the entire universe, with galaxies, black holes, supernova explosions, with everything we can observe in the real universe, to add to this virtual universe, to understand really what’s causing every piece that we see.”

Tom Fish
Express UK

Headline image: NASA, ESA and the HST Frontier Fields team (STScI), Acknowledgement: Judy Schmidt

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SpaceX’s Starship May Fly for Just $2 Million Per Mission, Elon Musk Says

The big spaceship-rocket duo will use just $900,000 of fuel per launch.

SAN FRANCISCO — Each flight of SpaceX’s big Mars-colonizing spacecraft will have a very small price tag, if all goes according to plan.

The Starship system, which consists of a reusable 100-passenger spaceship stacked atop a huge reusable rocket known as Super Heavy, will use just $900,000 worth of propellant to get off Earth and into orbit, Elon Musk said here today (Nov. 5) at the first U.S. Air Force Space Pitch Day.

“If you consider operational costs, maybe it’ll be like $2 million” out of SpaceX’s pocket each time, Musk said during a conversation with Lt. Gen. John Thompson, commander of the Space and Missile Systems Center, Air Force Space Command, at Los Angeles Air Force Base.

“This is much less than even a tiny rocket,” Musk added. “So, it’s something that needs to be made.”

An aerial view of SpaceX’s Starship Mk1 prototype, seen during Elon Musk’s Starship update in South Texas on Sept. 28, 2019.
(Image: © SpaceX)

During Space Pitch Day (which should be called Space Pitch Days, since it runs through tomorrow), companies try to sell Air Force brass on their space-related ideas. In keeping with this focus, Thompson mostly asked Musk about business stuff — how to spur innovation, how management and leadership styles shift as a company grows, and so on.

This may sound relatively dry to space geeks, but Musk injected some fun nuggets into the conversation. For example, the billionaire entrepreneur said he does “zero market research whatsoever,” striving instead to create the Platonic ideal of a rocket or car. (Musk is also CEO of electric-vehicle maker Tesla.)

If he pulls that off, then “people will want to buy it,” Musk said.

The Starship MK1 assembled at SpaceX’s build and launch facility in Texas.
(Image credit: SpaceX)

He also hyped Tesla’s new pickup truck, saying that “it looks like an armored personnel carrier from the future,” and announced that he had just finished watching the 1996 movie “Space Jam” (serially, during 15- to 20-minute morning workout stints on the treadmill).

Musk demurred when Thompson asked about his leadership qualities, saying he doesn’t consider himself an expert on leadership. Thompson urged Musk not to “sell himself short” in this regard, teeing up a self-deprecating joke that the billionaire jumped on.

“That’s true. There’s plenty of others doing that,” Musk said, referring to investors who are betting on the stock price of his companies (particularly Tesla) to fall.

Toward the end of the 40-minute conversation, Thompson gave Musk the floor to say anything he wanted to the audience of investors, engineers, entrepreneurs and military officials. The SpaceX founder and CEO took the opportunity to talk about something near and dear to his heart: the importance of fully and rapidly reusable orbital rockets.

This is the technological advance that will slash the cost of spaceflight by orders of magnitude, allowing humanity to become a truly spacefaring species, Musk has said repeatedly over the years.

“It’s absolutely profound to have a reusable rocket,” he said here today. “This is the holy grail.”

SpaceX founder and CEO Elon Musk chats with Lt. Gen. John Thompson, commander of the Air Force Space Command’s Space and Missile Systems Center, which is based at Los Angeles Air Force Base. The conversation took place in San Francisco on Nov. 5, 2019, at the U.S. Air Force’s first Space Pitch Day.
(Image credit: MIke Wall/Space.com)

SpaceX has been working to make this vision a reality, and the company has made considerable progress. SpaceX now routinely lands and reflies the first stages of its workhorse Falcon 9 rocket, and it’s doing the same with the heavy-lift Falcon Heavy, which has three launches under its belt. The company is now also starting to recover and refly payload fairings, the protective nose cones that surround satellites during launch. (There is still work to do, however; for example, the second stage of the Falcon 9 and Falcon Heavy is still single-use hardware.)

Starship and Super Heavy fit well into this grand vision. Both vehicles (the spaceship, like the overall architecture, is known as Starship) will be fully reusable, and each individual craft will fly many times before it’s retired, Musk has said.

These missions will be quite varied. Starship and Super Heavy are designed primarily to help humanity settle Mars, the moon and other deep-space destinations, but SpaceX wants the duo to take over all of the company’s needs eventually. So, if all goes according to plan, Starship will also launch satellites (perhaps starting as early as 2021) and maybe even clean up space junk and ferry people on point-to-point trips around Earth, Musk has said.

Being able to do all of this for $2 million a pop would be revolutionary. That would be the cost of each mission for SpaceX, to be clear; we don’t yet know how much the company will charge customers for a Starship mission (or “is charging,” for Japanese billionaire Yusaku Maezawa has already booked a round-the-moon flight on the vehicle, with a target launch date of 2023).

But, for some perspective, SpaceX currently sells Falcon 9 and Falcon Heavy launches for $62 million and $90 million, respectively. And those prices are considerably lower than similar services offered by SpaceX’s competitors.

Source www.space.com

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