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Unified model of active galactic nucleus confirmed by VLTI – Vaughan Today

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L ‘Avalanche Black hole theory confirmations with a statement fromwho – which Who accompanies printed in the famous newspaper temper nature Which can be freely referenced in arXiv. In 2015, we celebrated Centenary of Einstein’s final discovery of his theory of general relativity In the same year, gravitational waves were discovered on Earth for the first time from another amazing prediction of his theory of relativity gravity, black holes. In 2019, the first image of a black hole taken was revealed toevent horizon telescopeThe black hole at the heart of galaxy M87.

For decades it was believed that these stars Relativity in its supermassive form, that is, it contains at least one million people masses Solar energy, sometimes several billion, is the origin of active galactic nuclei (AGN where active galactic nucleus, in English) has been particularly highlighted by radio astronomers, but also by Astronomy scientists Without AGN necessarily being sources radio. These active galactic nuclei are characterized by particularly active phenomena of one form or another, for example Jets of relativistic matter over thousands of light yearsa discovery that interests them and which is now at the fore thanks to the observations made withInterferometer the very large telescope European Southern Observatory (ESO’s VLTI).

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Active galactic nuclei (AGNs) are highly energetic sources fueled by supermassive black holes. This short video provides insight into these particular objects through the recent discovery of an active galactic nucleus in the center of the Messier 77 galaxy. European Southern Observatory (which – which)

A zoo of active galactic cores

The most exciting active galactic nuclei are quasars Which at first glance seems stars seen at telescope While they are powerful radio sources, their precise determination of the distances observed in the early 1960s led to the recognition that they were objects whose size wasthe size the solar systemable, however, to launch as many as possibleenergy of great stars galaxy It’s all like the Milky Way.

In the end, astronomers understood that AGNs can be described in three main categories, radio galaxies, de sievert galaxies and the quasars with partitions. Some are very bright both in the visible and in the radio, and others are in only one of these spectral ranges. Some have jets of Themeothers do not.

Thus, radio galaxies are rather ordinary looking galaxies elliptical galaxies giants or lenticular galaxies, but emit strongly in the radio field. The emitted radio radiation can be hundreds of times stronger than that of so-called ordinary galaxies – we know for example the state of the so-called source chicken, which is a million times brighter than our Milky Way. An important feature of radio galaxies is their presence, and sometimes thousands of themlight years From their center, from the two lobes where mostepisode radio. This is the end of very high ejection material jets Speed The ones we mentioned earlier and in which we can see an artist’s illustration in the video above.

sievert galaxies are spiral galaxies It was first observed in 1943 by Karl Seifert. We can mention galaxies NGC 1410 in constellation From Eridano and Messier 77 in the Baleine region. It is much brighter than an ordinary galaxy, not only in the radio, but also in the visible with its nucleus in particular emitting as much light as the rest of the stars of these galaxies.

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Jean-Pierre Lumenet, director of research at CNRS and Françoise Coombes, professor at Collège de France, spoke to us about black holes and especially supermassive black holes in galaxies that lie behind AGNs. © Fondation Hugot of the College of France

We ended up developing the idea, described by the so-called Unified Model of AGN, that behind all these AGNs were hiding the same type of object, but seen from different angles and at different time intervals.beingit has been said, supermassive black holes that emit a huge amount of energy after complex, and not always well understood, processesaccumulation of matter (Mainly in the form of cold bristles) and relative hydrodynamics.

Thus, in a region almost no larger than the solar system at most, there must be a hoop of dust and Gas ambient neutrals a Accumulation disk of dust, gas, and finally matter ionized by the heat emitted by the viscous friction in this disk and falling on a black hole care alternately.

Hot plasma enters the atmosphere of a black hole, that is, a regionspacetime Any falling object rotates radially, then participates in a complex mechanism, explained in part by Blandford and Znajik, in which the gravitational energy of falling matter and especially the rotational energy of a black hole is converted into intense radiation and jets of matter along the axis of rotation of the compressed star.

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Astronomers have observed different types of AGNs. Some, called blazars, are very bright and can show differences in brightness over time scales of only hours or days, while another type, called quasars, are also very bright but tend to show lower fluctuations than blazars. Severt galaxies, which come in two forms (1 and 2), are another type of active galactic nucleus, surrounded by easily detectable host galaxies. The galaxies Seyfert 1 and Sefert 2 have a bright core. However, those of the Seyfert 2 type tend to be more conservative. The unified AGN model states that despite their differences, all AGNs have the same basic structure: a supermassive black hole surrounded by a thick ring, or hoop, of dust. According to this model, any difference in appearance between AGNs results from the angle from which we observe the black hole and its massive ring from Earth. Thus, the type of active galactic nuclei we observe depends on how dark the black hole is along its line of sight, sometimes completely obscured by the ring. © European Southern Observatory (ESO), L. Calçada and M. Kornmesser

Unified model of active galactic nuclei

Today, it is therefore a teamastrophysicists, led by doctoral student Violetta Jamez-Rosas from Leiden University in the Netherlands, who has just provided new evidence of the importance of a unified AGN model by making the most accurate observations yet of the galactic center. 47 million light-years from the Milky Way in the constellation Pisces, revealing a thick disk of cosmic dust and gas hiding giant black hole.

ESO press release revealing this discovery, made possible by the Matisse tool (Medium Infrared Multiple Spectrophotometer) Installed on the VLTI, he presents it as a very serious confirmation of the viability of the unified model developed thirty years ago. located in desert From Atacama in Chile, this machine collects light Infrared They were collected by the four 8.2-meter telescopes that make up very large telescope (VLT) from ESO using a technology called Interferometry The optics are long base, which actually makes it possible to have a much larger telescope, powerful Precision Superior detail control like never before.

« Matisse is able to detect a wide range of wavelengths Infrared, allowing us to see dust and measure temperatures accurately. Since the VLTI consists of a very large interferometer, it provides sufficient resolution to study phenomena that occur within distant galaxies such as Messier 77. The obtained images show differences in temperature andabsorb From clouds Gas around a black hole ‘,” outlines Walter Jaffe, co-author of the study and professor at Leiden University.

« The true nature of dust clouds, their role in feeding the black hole, as well as the appearance they take on as seen from Earth, have long been fundamental questions for any researcher working on active galactic nuclei. Although no single result can answer all the questions that arise, a major step has just been taken in our understanding of how AGNs work.explains Violetta Gamez Rosas who adds, Our results should provide a better understanding of the inner workings of the AGN. It could also help us better understand the history of the Milky Way, which has a supermassive black hole at its center that may have been active in the past. »

The researchers now want to extend their observations, using ESO’s VLTI, to a larger sample of galaxies, in order to confirm the validity of the unified AGN model.

Bruno Lopez, l’un des membres de l’équipe et responsable principal de l’instrument Matisse à l’Observatoire de la Côte d’Azur, situé à Nice en France, ajoute quant à lui et toujours dans le communiqué de l’ESO that : “ Messier 77 is a true AGN prototype. His study prompts us to expand our observations program and improve Mattis in order to study a larger sample of AGNs. ».

This research program should take on a new dimension when itvery large telescope (ELT) of ESO will enter service before the end of this contract.

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« Very greedy supermassive black holes. All galaxies have a supermassive black hole at their center, the masses of which range from one million to a few billion solar masses. There is a proportional relationship between the mass of these black holes and the mass of galactic bulges, indicating that star formation and black hole feeding occur simultaneously. Somehow, galaxies and their black holes grow in a symbiosis. When gas falls toward the center of the galaxy, the black hole swallows as much of it as possible, but the mass it can absorb is limited. The fall of matter into the black hole releases a great deal of energy, in the form of radiation, and also in the form of kinetic energy. A galactic nucleus becomes active, either a sievert nucleus or a quasar. Winds and jets of plasma from the black hole attract the surrounding interstellar gas. Molecular gas flows around active cores have recently been revealed, carrying so much mass that they can have a major impact on host galaxy evolution, regulating or even halting the gas supply to star formation. Voracious black holes, by spitting out their own food, regulate star formation. We will explain in detail these phenomena, perhaps at the origin of the proportionality between the masses of black holes and LEDs. Françoise Combs is an astronomer at the Paris Observatory in the Laboratory for the Study of Radiation and Matter in Astrophysics (Lerma). His current field of research concerns the formation and evolution of galaxies. © Ecole Normale Supérieure – PSL

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Toward customizable timber, grown in a lab – EurekAlert

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image: In an effort to provide an environmentally friendly and low-waste alternative, researchers at MIT have pioneered a tunable technique to generate wood-like plant material in a lab.
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Credit: Image courtesy of Luis Fernando Velásquez-García, Ashley Beckwith, et al

Each year, the world loses about 10 million hectares of forest — an area about the size of Iceland — because of deforestation. At that rate, some scientists predict the world’s forests could disappear in 100 to 200 years.

In an effort to provide an environmentally friendly and low-waste alternative, researchers at MIT have pioneered a tunable technique to generate wood-like plant material in a lab, which could enable someone to “grow” a wooden product like a table without needing to cut down trees, process lumber, etc.

These researchers have now demonstrated that, by adjusting certain chemicals used during the growth process, they can precisely control the physical and mechanical properties of the resulting plant material, such as its stiffness and density.

They also show that, using 3D bioprinting techniques, they can grow plant material in shapes, sizes, and forms that are not found in nature and that can’t be easily produced using traditional agricultural methods.

“The idea is that you can grow these plant materials in exactly the shape that you need, so you don’t need to do any subtractive manufacturing after the fact, which reduces the amount of energy and waste. There is a lot of potential to expand this and grow three-dimensional structures,” says lead author Ashley Beckwith, a recent PhD graduate.

Though still in its early days, this research demonstrates that lab-grown plant materials can be tuned to have specific characteristics, which could someday enable researchers to grow wood products with the exact features needed for a particular application, like high strength to support the walls of a house or certain thermal properties to more efficiently heat a room, explains senior author Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories.

Joining Beckwith and Velásquez-García on the paper is Jeffrey Borenstein, a biomedical engineer and group leader at the Charles Stark Draper Laboratory. The research is published today in Materials Today.

Planting cells

To begin the process of growing plant material in the lab, the researchers first isolate cells from the leaves of young Zinnia elegans plants. The cells are cultured in liquid medium for two days, then transferred to a gel-based medium, which contains nutrients and two different hormones.

Adjusting the hormone levels at this stage in the process enables researchers to tune the physical and mechanical properties of the plant cells that grow in that nutrient-rich broth.

“In the human body, you have hormones that determine how your cells develop and how certain traits emerge. In the same way, by changing the hormone concentrations in the nutrient broth, the plant cells respond differently. Just by manipulating these tiny chemical quantities, we can elicit pretty dramatic changes in terms of the physical outcomes,” Beckwith says.

In a way, these growing plant cells behave almost like stem cells — researchers can give them cues to tell them what to become, Velásquez-García adds.

They use a 3D printer to extrude the cell culture gel solution into a specific structure in a petri dish, and let it incubate in the dark for three months. Even with this incubation period, the researchers’ process is about two orders of magnitude faster than the time it takes for a tree to grow to maturity, Velásquez-García says.

Following incubation, the resulting cell-based material is dehydrated, and then the researchers evaluate its properties.

Wood-like characteristics

They found that lower hormone levels yielded plant materials with more rounded, open cells that have lower density, while higher hormone levels led to the growth of plant materials with smaller, denser cell structures. Higher hormone levels also yielded plant material that was stiffer; the researchers were able to grow plant material with a storage modulus (stiffness) similar to that of some natural woods.

Another goal of this work is to study what is known as lignification in these lab-grown plant materials. Lignin is a polymer that is deposited in the cell walls of plants which makes them rigid and woody. They found that higher hormone levels in the growth medium causes more lignification, which would lead to plant material with more wood-like properties.

The researchers also demonstrated that, using a 3D bioprinting process, the plant material can be grown in a custom shape and size. Rather than using a mold, the process involves the use of a customizable computer-aided design file that is fed to a 3D bioprinter, which deposits the cell gel culture into a specific shape. For instance, they were able to grow plant material in the shape of a tiny evergreen tree.

Research of this kind is relatively new, Borenstein says.

“This work demonstrates the power that a technology at the interface between engineering and biology can bring to bear on an environmental challenge, leveraging advances originally developed for health care applications,” he adds.

The researchers also show that the cell cultures can survive and continue to grow for months after printing, and that using a thicker gel to produce thicker plant material structures does not impact the survival rate of the lab-grown cells.

“Amenable to customization”

“I think the real opportunity here is to be optimal with what you use and how you use it. If you want to create an object that is going to serve some purpose, there are mechanical expectations to consider. This process is really amenable to customization,” Velásquez-García says.

Now that they have demonstrated the effective tunability of this technique, the researchers want to continue experimenting so they can better understand and control cellular development. They also want to explore how other chemical and genetic factors can direct the growth of the cells.

They hope to evaluate how their method could be transferred to a new species. Zinnia plants don’t produce wood, but if this method were used to make a commercially important tree species, like pine, the process would need to be tailored to that species, Velásquez-García says.  

Ultimately, he is hopeful this work can help to motivate other groups to dive into this area of research to help reduce deforestation.

“Trees and forests are an amazing tool for helping us manage climate change, so being as strategic as we can with these resources will be a societal necessity going forward,” Beckwith adds.

This research is funded, in part, by the Draper Scholars Program.

###

Written by Adam Zewe, MIT News Office

Additional background

Paper: “Physical, mechanical, and microstructural characterization of novel, 3D-printable, tunable, lab-grown plant materials generated from Zinnia elegans cell cultures”

https://www.sciencedirect.com/science/article/pii/S1369702122000451


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Crumbling comet could create meteor shower May 30 – Northern Daily News

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A crumbling comet could create a meteor shower on May 30.

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The ‘tau Herculids’ meteor display might be one of the most dramatic observed in over two decades, according to Space.com.

Meteor showers occur when dust or particles from asteroids or comets enter Earth’s atmosphere at a very high speed, the U.K. Sun explained.

This one is expected to be the product of a comet named 73P/Schwassmann-Wachmann, also known as SW3.

SW3 was first discovered in 1930 but did not reappear again until the 1970s, Republic World reported.

In 1995, astronomers noticed that the comet’s nucleus split into four smaller chunks, according to CNET.

It has continued to disintegrate more in the ensuing years.

The display is expected to be very visible in the Northern Hemisphere as it is occurring on a Moon-less night.

A consensus of experts predicts that the shower will be visible starting from 1 a.m. EST on May 31.

It is suggested viewers will want to be outside at least an hour before this so your eyes have a chance to adjust to the dark.

“The southwestern USA and Mexico are favored locations as the radiant, the area of the sky where these meteors come from, will be located highest in a dark sky,” Robert Lunsford wrote for AMS.

“The outburst may be seen from southeastern Canada and the remainder of the (eastern) USA, but at a lower altitude.”

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Boeing capsule lands back on Earth after space shakedown – Phys.org

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Boeing’s CST-100 Starliner spacecraft lands at White Sands Missile Range’s Space Harbor, Wednesday, May 25, 2022, in New Mexico. Credit: Bill Ingalls/NASA via AP

Boeing’s crew taxi returned to Earth from the International Space Station on Wednesday, completing a repeat test flight before NASA astronauts climb aboard.

It was a quick trip back: The Starliner capsule parachuted into the New Mexico desert just four hours after leaving the orbiting lab, with airbags attached to cushion the landing. Only a mannequin was buckled in.

Aside from thruster failures and cooling system snags, Starliner appeared to clinch its high-stakes shakedown cruise, 2 1/2 years after its botched first try. Flight controllers in Houston applauded and cheered the bull’s-eye touchdown.

“It’s great to have this incredible test flight behind us,” said Steve Stich, director of NASA’s commercial crew program. He described the demo as “extremely successful,” with all objectives met.

Added Boeing’s Mark Nappi, a : “On a scale of one to 10, I think I’d give it a 15.”

Based on these early results, NASA astronauts will strap in next for a trip to the , perhaps by year’s end. The has long wanted two competing U.S. companies ferrying astronauts, for added insurance as it drastically reduced its reliance on Russia for rides to and from the space station.

Boeing capsule lands back on Earth after space shakedown
Boeing’s CST-100 Starliner spacecraft lands at White Sands Missile Range’s Space Harbor, Wednesday, May 25, 2022, in New Mexico. Credit: Bill Ingalls/NASA via AP

Elon Musk’s SpaceX is already the established leader, launching astronauts since 2020 and even tourists. Its crew capsules splash down off the Florida coast, Boeing’s Starliner returns to the Army’s expansive and desolate White Sands Missile Range in New Mexico.

Boeing scrapped its first attempt to reach the space station in 2019, after software errors left the capsule in the wrong orbit and nearly doomed it. The company fixed the flaws and tried again last summer, but corroded valves halted the countdown. Following more repairs, Starliner finally lifted off from Cape Canaveral last Thursday and docked to the space station Friday.

Station astronauts tested Starliner’s communication and computer systems during its five days at the space station. They also unloaded hundreds of pounds (kilograms) of groceries and other supplies that flew up in the Boeing capsule, then filled it with empty air tanks and other discarded gear.

  • Boeing capsule lands back on Earth after space shakedown
    In this infrared image from video made available by NASA, the Boeing Starliner capsule uses parachutes as it descends to land at the White Sands Missile Range in New Mexico on Wednesday, May 25, 2022. Credit: NASA via AP
  • Boeing capsule lands back on Earth after space shakedown
    In this image from video made available by NASA, the Boeing Starliner capsule, upper center, leaves the International Space Station on Wedndesday, May 25, 2022. At bottom foreground is a SpaceX Dragon capsule, still docked to the station. Credit: NASA via AP

A folded U.S. flag sent up by Boeing stayed behind, to be retrieved by the first Starliner crew.

“We’re a little sad to see her go,” station astronaut Bob Hines radioed as the capsule flew away.

Along for the ride was Starliner’s test dummy—Rosie the Rocketeer, a takeoff on World War II’s Rosie the Riveter.

The repairs and do-over cost Boeing nearly $600 million.


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Boeing docks crew capsule to space station in test do-over


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