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  • richardmitnick 11:37 pm on December 21, 2020 Permalink | Reply
    Tags: "Euclid's optical and infrared instruments integrated in spacecraft", Astronomy, , , , Dark energy and dark matter in space, ,   

    From European Space Agency – United Space in Europe (EU): “Euclid’s optical and infrared instruments integrated in spacecraft” 

    ESA Space For Europe Banner

    From European Space Agency – United Space in Europe (EU)

    21 December 2020

    Giuseppe Racca
    ​​​​​​​Euclid Project Manager
    ​​​​​​​Directorate of Science
    ​​​​​​​European Space Agency
    Email: giuseppe.racca@esa.int

    René Laureijs
    ​​​​​​​Euclid Project Scientist
    ​​​​​​​Directorate of Science
    ​​​​​​​European Space Agency
    ​​​​​​​Email: rene.laureijs@esa.int

    ESA/Euclid spacecraft depiction.

    The optical and infrared instruments of Euclid, ESA’s mission to study dark energy and dark matter in space, have passed their qualification and acceptance reviews and are now fully integrated into the spacecraft’s payload module. This marks an important step forward in the assembly of the Euclid space telescope, which is scheduled for launch in 2022.

    1
    The Euclid payload module. Credit: Airbus Defence and Space – Toulouse.

    The two Euclid instruments, the visible imager (VIS) and the near infrared spectrometer and photometer (NISP), were integrated onto the payload module of the spacecraft by Airbus Defence and Space in Toulouse, France. This module is built up from a silicon baseplate, containing the two instruments on one side, and the main mirror of the telescope on the other.

    “It has been a complicated process to design and build the module,” explains Giuseppe Racca, ESA’s Euclid project manager. “Because the large baseplate is fully made out of silicon carbide, a ceramic material had to be moulded to accommodate the instruments at an extreme precision. Due to its large size it consists of four pieces that were combined as one. We are very happy that assembling and alignment of the optics and instruments have now been finalised.”

    2
    CAD model of Euclid payload module. Credit: Airbus Defence and Space – Toulouse.

    The visible and infrared instruments are crucial to measure both the shapes and redshift of distant galaxies and clusters of galaxies. This will enable scientists to reconstruct the past 10 billion years of the Universe’s expansion history, and investigate the mysterious dark matter and dark energy that are thought to dominate the Universe.

    After the successful integration of both instruments and the telescope, the so-called ‘cold units’, the payload module will be shipped to Centre Spatial de Liège, Belgium in April 2021. There, the instruments will be tested for optical compatibility and performance at the operating temperatures in space (ranging from -193°C to +17°C).

    “We want to make sure that the instruments perform as predicted. Therefore, we will perform tests in a thermal vacuum chamber that can simulate the conditions of space as well as possible on Earth,” says René Laureijs, ESA’s project scientist for Euclid.

    3
    Euclid payload with the visual instrument exposed. Credit: Airbus Defence and Space – Toulouse.

    Also present at the testing site in Belgium will be the service module panel containing the so-called ‘warm units’ such as computers and power supplies.

    Once compatibility and performance tests show that everything is working as expected, the payload module and warm units panel will be shipped to Thales Alenia Space in Torino, Italy, where they will be integrated to form the final, finished spacecraft. Then, another round of tests will ensure that everything is working together properly. At that point, the spacecraft is essentially finished, and ready for launch.

    Launch is currently scheduled for the second half of 2022 from Europe’s spaceport, Kourou, French Guiana. Euclid will be orbiting the second Sun-Earth Lagrangian Point (L2), which is located 1.5 million kilometres directly ‘behind’ the Earth as viewed from the Sun.

    About the Euclid instruments

    Within ESA’s overall coordination, the Euclid instruments were designed and built by the Euclid Consortium, a collaboration of nationally funded institutes responsible for the definition of the scientific mission and the provision of the scientific instruments and data processing. The VIS instrument was built by a consortium of nationally funded institutes led by Mullard Space Science Laboratory (MSSL), University College London, UK. The NISP instrument was built by a consortium of nationally funded institutes led by the Laboratoire d’Astrophysique de Marseille (LAM) in France; its detectors are provided by NASA.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The European Space Agency (ESA) (EU), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 11:23 pm on December 21, 2020 Permalink | Reply
    Tags: "Astrophysics- How nearby galaxies form their stars", Astronomy, , , , University of Zürich [Universität Zürich](CH)   

    From University of Zürich [Universität Zürich](CH): “Astrophysics- How nearby galaxies form their stars” 

    From University of Zürich [Universität Zürich](CH)

    11 Dec 2020 [Just now in social media]
    Universität Zürich
    Institute for Computational Science
    Center for Theoretical Astrophysics and Cosmology
    Prof. Robert Feldmann
    feldmann@physik.uzh.ch

    1
    How stars form in galaxies remains a major open question. Robert Feldmann sheds new light on this topic with the help of a data-driven re-analysis of observational measurements.

    Stars are born in dense clouds of molecular hydrogen gas that permeates interstellar space of most galaxies. While the physics of star formation is complex, recent years have seen substantial progress towards understanding how stars form in a galactic environment. What ultimately determines the level of star formation in galaxies, however, remains an open question.

    In principle, two main factors influence the star formation activity: the amount of molecular gas that is present in galaxies and the timescale over which the gas reservoir is depleted by converting it into stars. While the gas mass of galaxies is regulated by a competition between gas inflows, outflows, and gas consumption, the physics of the gas-to-star conversion is currently not well understood. Given its potentially critical role, many efforts have been undertaken to determine the gas depletion timescale observationally. However, these efforts resulted in conflicting findings partly because of the challenge in measuring gas masses reliably given current detection limits.

    2
    Figure 1 Visualization of gas in and around a Milky-Way-like galaxy (center) in today’s Universe as predicted by a cosmological simulation run by the author. Dense, atomic and molecular hydrogen typically forms an extended disk, here seen in bluish-purple at the center of the image. Stars (white) form throughout the gas disk. Additional star formation may take place in satellite galaxies, here seen at the top right and bottom left positions. Hot, low density gas (green and red hues) can be found at large distances, out to the edge of the dark matter halo surrounding the main galaxy (white circle). The image also shows a large number of dark matter substructures (purple) most of which are devoid of gas and stars.

    The present study uses a new statistical method based on Bayesian modeling to properly account for galaxies with undetected amounts of molecular or atomic hydrogen to minimize observational bias. This new analysis reveals that, in typical, star forming galaxies, molecular and atomic hydrogen are converted into stars over approximately constant timescales of 1 and 10 billion years, respectively. However, extremely active galaxies (`starbursts’) are found to have much shorter gas depletion timescales. These findings suggest that star formation in typical galaxies is indeed directly linked to the overall gas reservoir and thus set by the rate at which gas enters or leaves a galaxy. In contrast, the dramatically higher star formation activity of starbursts has likely a different physical origin, such as galaxy interactions or instabilities in galactic disks.

    This analysis is based on observational data of nearby galaxies. Observations with the Atacama Large Millimeter/submillimeter Array, the Square Kilometer Array, and other observatories promise to probe the gas content of large numbers of galaxies across cosmic history.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres.

    Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

    It will be paramount to continue the development of statistical and data science methods to accurately extract the physical content from these new observations and to fully uncover the mysteries of star formation in galaxies.

    Science paper:
    The link between star formation and gas in nearby galaxies
    Communication Physics

    See the full article here .

    Please help promote STEM in your local schools.


    Stem Education Coalition

    The University of Zürich (CH)(Universität Zürich), located in the city of Zürich, is the largest university in Switzerland, with over 26,000 students. It was founded in 1833 from the existing colleges of theology, law, medicine and a new faculty of philosophy.

    Currently, the university has seven faculties: Philosophy, Human Medicine, Economic Sciences, Law, Mathematics and Natural Sciences, Theology and Veterinary Medicine. The university offers the widest range of subjects and courses of any Swiss higher education institutions.

     
  • richardmitnick 6:10 pm on December 21, 2020 Permalink | Reply
    Tags: "This May Be the First Complete Observation of a Nanoflare", Astronomy, , , , ,   

    From NASA Goddard Space Flight Center: “This May Be the First Complete Observation of a Nanoflare” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Dec. 21, 2020
    Miles Hatfield
    miles.s.hatfield@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1

    Researchers may have found the long-sought “nanoflares” thought to heat the solar corona to its incredible temperatures.

    A new study published in Nature Astronomy marks the first time researchers have captured the full lifecycle of a putative nanoflare – from bright origins to blistering demise.

    Mini flares for a major puzzle

    Nanoflares are tiny eruptions on the Sun, one-billionth the size of normal solar flares. Eugene Parker – of Parker Solar Probe fame – first predicted them in 1972 to solve a major puzzle: the coronal heating problem.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker.

    That’s the mystery of how the Sun’s outer atmosphere, or corona, gets so incredibly hot. Despite being much farther away from the solar core, it’s millions of degrees hotter than the layers beneath it.

    Nearly 50 years later the coronal heating problem still hasn’t been solved. It has been hard to confirm any of a handful of different theories, in part because no one has ever actually seen a nanoflare.

    2
    The coronal heating problem is one of several mind-melting facts about the Sun.
    Credit: NASA/Miles Hatfield/Mary Pat Hrybyk-Keith.

    “They’re extremely difficult to observe,” said Shah Bahauddin, Research Faculty at the Laboratory of Atmospheric and Space Physics at the University of Colorado, Boulder, and lead author of the study.

    Tiny and brief, our best telescopes have only recently become powerful enough to resolve them. And seeing a tiny flash isn’t enough – it takes a lot be considered a true nanoflare sighting. “We know from theory what we should look for – what fingerprint a nanoflare would leave,” Bahauddin said.

    A nanoflare by any other name

    To say you’ve observed a corona-heating nanoflare, you have to check at least two major boxes.

    First, like regular flares, a nanoflare is set alight by magnetic reconnection. If the eruption you’re seeing is heated by some other process, it’s not a nanoflare.

    Magnetic reconnection is triggered when magnetic field lines explosively realign. Unlike other mechanisms that heat things up gradually, it can take relatively cool plasma and make it super-hot in an instant.

    “It’s like putting two ice cubes together and suddenly the temperature rises to 1000 degrees Fahrenheit,” Bahauddin said.

    One way to spot heating via magnetic reconnection is to observe intense heat amidst far cooler surroundings.

    Second, the nanoflare has to heat the corona, which might lie thousands of miles above where they erupt. That’s not trivial – many other solar eruptions only heat their immediate surroundings.

    “You have to examine if the energy from a nanoflare can be dissipated in the corona,” Bahauddin said. “If the energy goes somewhere else, that doesn’t solve the coronal heating problem.”

    A counterintuitive finding becomes a key puzzle piece

    When Bahauddin started this research as a PhD student, he wasn’t thinking about nanoflares at all. Looking for a project, he decided to investigate some tiny bright loops – at about 60 miles across, they are tiny on Sun scales – that he’d noticed flickering in the layer just below the super-hot corona.

    “I thought maybe the loops made the surrounding atmosphere a bit hotter,” he said. “I never thought that it would make so much energy that it might actually propel hot plasma to the corona and heat it up.”

    3
    A close-up of one of the loop brightenings studied in the article. Each inset frame zooms in to the selected region in the frame to its left. The frame on the far right is the most zoomed in, showing the putative nanoflare.
    Credit: NASA/SDO/IRIS/Shah Bahauddin.

    But as Bahauddin zoomed in on images taken by NASA’s Interface Region Imaging Spectrograph, or IRIS satellite, he uncovered two surprises.

    NASA IRIS Interface Region Imaging Spectrograph

    First, these loops were incredibly hot – millions of degrees hotter than their surroundings.

    But even stranger, this heat was distributed in an unusual way – differently than in most other physical systems.

    While the Sun is made mostly of hydrogen and helium, it also contains smaller amounts of every other element. In these loops, somehow the heavier elements – such as silicon, which has 14 protons in its nucleus – were much hotter and more energetic than lighter elements, such as oxygen, which has only eight.

    “If you push a ball that is very light across the floor, it should roll farther than a heavy ball,” said Bahauddin. “Yet, in our case, the heavier elements were shooting out at about 60 miles per second, while the lighter ones were almost at zero. That was completely counterintuitive.”

    This strange observation told them that something very specific must be happening in these bright loops.

    “That was a big clue,” said Amy Winebarger, solar physicist at NASA’s Marshall Space Flight Center in Huntsville, Alabama, and coauthor of the study. “You really had to start thinking about what kind of heating could impact the oxygen atom differently than the silicon atom.”

    Bahauddin spent the following years running computer simulations, testing out different heating mechanisms. He needed to find one that could match their observations, including heating the heavier elements more than the lighter ones.

    In the end, only one heating mechanism could produce the effect. The heat had to come from a magnetic reconnection event – the same driving force behind solar flares.

    The key was in the aftermath. As magnetic field lines twist and re-align, they create a brief electric current that accelerates the newly-freed ions. Bahauddin likens it to a panicked crowd.

    “It’s like everyone in a room is trying to run at the same time. They start to collide with each other, and there’s a big mess,” Bahauddin said.

    Critically, the longer an ion can keep moving in an electric field, the more energy it gains. This is where heavier ions, like silicon, have an advantage. “Since they have more momentum, they can plow through the crowd and steal all the available energy,” Bahauddin said.

    In other words, the more massive silicon ions bulldozed their way through the chaos, soaking up the energy from the electric field. The lighter oxygen ions couldn’t do that – they were stopped dead in their tracks after each collision.

    This mechanism could explain their results, but still, it was a longshot. The simulations showed that this process only happened under quite specific conditions.

    “To make this happen you needed a specific temperature, and you needed the right proportion of silicon to oxygen,” Bahauddin said. “So we looked back at the measurements, and saw that the numbers exactly matched.” Remarkably, the conditions on the Sun mirrored his simulations.

    Heating the corona

    So far, these bright loops appeared to be tiny flares – but did their heat actually reach the corona?

    Bahauddin looked to NASA’s Solar Dynamics Observatory, which carries telescopes tuned to see the extremely hot plasma only found in the corona. Bahauddin located the regions right above the brightenings shortly after they appeared.

    NASA/SDO.

    “And there it was, just a 20-second delay,” Bahauddin said. “We saw the brightening, and then we suddenly saw the corona got super-heated to multi-million degree temperatures,” Bahauddin said. “SDO gave us this important information: Yes, this is indeed increasing the temperature, transferring energy to the corona.”

    Bahauddin documented 10 instances of bright loops with similar effects on the corona. Still, he hesitates to call them nanoflares. “Nobody actually knows because nobody has seen it before,” Bahauddin said. “It’s an educated guess, let’s say.”

    From the perspective of the theory that says nanoflares heat the corona, the only thing left to do is to show that these brightenings occur often enough, all over the Sun, to account for the corona’s extreme heat. That’s still work in progress. But observing these tiny bursts as they heat solar atmosphere is a compelling start.

    “We have shown how a cool, low-lying structure can actually supply super-hot plasma to the corona,” Bahauddin said. “That, to me, was the most beautiful thing.”

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


    NASA/Goddard Campus

     
  • richardmitnick 2:01 pm on December 20, 2020 Permalink | Reply
    Tags: "The Universe Is Expanding Faster Than Expected", Astronomy, , , , , ESA/GAIA DR 3,   

    From WIRED: “The Universe Is Expanding Faster Than Expected” 


    From WIRED

    12.20.2020
    Natalie Wolchover

    1
    The Gaia telescope gauges the distances to stars by measuring their parallax, or apparent shift over the course of a year. Closer stars have a larger parallax. Credit: Samuel Velasco/Quanta Magazine.

    On December 3, humanity suddenly had information at its fingertips that people have wanted for, well, forever: the precise distances to the stars.

    “You type in the name of a star or its position, and in less than a second you will have the answer,” Barry Madore, a cosmologist at the University of Chicago and Carnegie Observatories, said on a Zoom call last week. “I mean …” He trailed off.

    “We’re drinking from a firehose right now,” said Wendy Freedman, also a cosmologist at Chicago and Carnegie and Madore’s wife and collaborator.

    “I can’t overstate how excited I am,” Adam Riess of Johns Hopkins University, who won the 2011 Nobel Prize in Physics for co-discovering dark energy, said in a phone call. “Can I show you visually what I’m so excited about?” We switched to Zoom so he could screen-share pretty plots of the new star data.

    Gaia EDR3 StarTrails 600.

    4
    Gaia EDR3. https://cds.unistra.fr/GaiaEDR3News

    The data comes from the European Space Agency’s Gaia spacecraft, which has spent the past six years stargazing from a perch 1 million miles high.

    ESA (EU)/GAIA satellite .

    The telescope has measured the “parallaxes” of 1.3 billion stars—tiny shifts in the stars’ apparent positions in the sky that reveal their distances. “The Gaia parallaxes are by far the most accurate and precise distance determinations ever,” said Jo Bovy, an astrophysicist at the University of Toronto.

    Best of all for cosmologists, Gaia’s new catalogue includes the special stars whose distances serve as yardsticks for measuring all farther cosmological distances. Because of this, the new data has swiftly sharpened the biggest conundrum in modern cosmology: the unexpectedly fast expansion of the universe, known as the Hubble tension.

    The tension is this: The cosmos’s known ingredients and governing equations predict that it should currently be expanding at a rate of 67 kilometers per second per megaparsec—meaning we should see galaxies flying away from us 67 kilometers per second faster for each additional megaparsec of distance. Yet actual measurements consistently overshoot the mark. Galaxies are receding too quickly. The discrepancy thrillingly suggests that some unknown quickening agent may be afoot in the cosmos.

    “It would be incredibly exciting if there was new physics,” Freedman said. “I have a secret in my heart that I hope there is, that there’s a discovery to be made there. But we want to make sure we’re right. There’s work to do before we can say so unequivocally.”

    That work involves reducing possible sources of error in measurements of the cosmic expansion rate. One of the biggest sources of that uncertainty has been the distances to nearby stars—distances that the new parallax data appears to all but nail down.

    In a paper posted online December 15 and submitted to The Astrophysical Journal [“Cosmic Distances Calibrated to 1% Precision with Gaia EDR3 Parallaxes and Hubble Space Telescope Photometry of 75 Milky Way Cepheids Confirm Tension with LambdaCDM”], Riess’s team has used the new data to peg the expansion rate at 73.2 kilometers per second per megaparsec, in line with their previous value, but now with a margin of error of just 1.8 percent. That seemingly cements the discrepancy with the far lower predicted rate of 67.

    Freedman and Madore expect to publish their group’s new and improved measurement of the cosmic expansion rate in January. They too expect the new data to firm up, rather than shift, their measurement, which has tended to land lower than Riess’s and those of other groups but still higher than the prediction.

    Since Gaia launched in December 2013, it has released two other massive data sets that have revolutionized our understanding of our cosmic neighborhood. Yet Gaia’s earlier parallax measurements were a disappointment. “When we looked at the first data release” in 2016, Freedman said, “we wanted to cry.”

    An Unforeseen Problem

    If parallaxes were easier to measure, the Copernican revolution might have happened sooner.

    Copernicus proposed in the 16th century that the Earth revolves around the sun. But even at the time, astronomers knew about parallax. If Earth moved, as Copernicus held, then they expected to see nearby stars shifting in the sky as it did so, just as a lamppost appears to shift relative to the background hills as you cross the street. The astronomer Tycho Brahe didn’t detect any such stellar parallax and thereby concluded that Earth does not move.

    And yet it does, and the stars do shift—albeit barely, because they’re so far away.

    It took until 1838 for a German astronomer named Friedrich Bessel to detect stellar parallax. By measuring the angular shift of the star system 61 Cygni relative to the surrounding stars, Bessel concluded that it was 10.3 light-years away. His measurement differed from the true value by only 10 percent—Gaia’s new measurements place the two stars in the system at 11.4030 and 11.4026 light-years away, give or take one or two thousandths of a light-year.

    The 61 Cygni system is exceptionally close. More typical Milky Way stars shift by mere ten-thousandths of an arcsecond—just hundredths of a pixel in a modern telescope camera. Detecting the motion requires specialized, ultra-stable instruments. Gaia was designed for the purpose, but when it switched on, the telescope had an unforeseen problem.

    The telescope works by looking in two directions at once and tracking the angular differences between stars in its two fields of view, explained Lennart Lindegren, who co-proposed the Gaia mission in 1993 and led the analysis of its new parallax data [Astronomy and Astrophysics “Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position”]. Accurate parallax estimates require the angle between the two fields of view to stay fixed. But early in the Gaia mission, scientists discovered that it does not. The telescope flexes slightly as it rotates with respect to the sun, introducing a wobble into its measurements that mimics parallax. Worse, this parallax “offset” depends in complicated ways on objects’ positions, colors and brightness.

    However, as data has accrued, the Gaia scientists have found it easier to separate the fake parallax from the real. Lindegren and colleagues managed to remove much of the telescope’s wobble from the newly released parallax data, while also devising a formula that researchers can use to correct the final parallax measurements depending on a star’s position, color and brightness.

    Climbing the Ladder

    With the new data in hand, Riess, Freedman and Madore and their teams have been able to recalculate the universe’s expansion rate. In broad strokes, the way to gauge cosmic expansion is to figure out how far away distant galaxies are and how fast they’re receding from us. The speed measurements are straightforward; distances are hard.

    The most precise measurements rely on intricate “cosmic distance ladders.” The first rung consists of “standard candle” stars in and around our own galaxy that have well-defined luminosities, and which are close enough to exhibit parallax—the only sure way to tell how far away things are without traveling there. Astronomers then compare the brightness of these standard candles with that of fainter ones in nearby galaxies to deduce their distances. That’s the second rung of the ladder. Knowing the distances of these galaxies, which are chosen because they contain rare, bright stellar explosions called Type 1a supernovas, allows cosmologists to gauge the relative distances of farther-away galaxies that contain fainter Type 1a supernovas. The ratio of these faraway galaxies’ speeds to their distances gives the cosmic expansion rate.

    Parallaxes are thus crucial to the whole construction. “You change the first step—the parallaxes—then everything that follows changes as well,” said Riess, who is one of the leaders of the distance ladder approach. “If you change the precision of the first step, then the precision of everything else changes.”

    Riess’s team has used Gaia’s new parallaxes of 75 Cepheids—pulsating stars that are their preferred standard candles—to recalibrate their measurement of the cosmic expansion rate.

    Freedman and Madore, Riess’s chief rivals at the top of the distance ladder game, have argued in recent years that Cepheids foster possible missteps on higher rungs of the ladder. So rather than lean too heavily on them, their team is combining measurements based on multiple kinds of standard-candle stars from the Gaia data set, including Cepheids, RR Lyrae stars, tip-of-the-red-giant-branch stars and so-called carbon stars.

    “Gaia’s [new data release] is providing us with a secure foundation,” said Madore. Although a series of papers by Madore and Freedman’s team aren’t expected for a few weeks, they noted that the new parallax data and correction formula appear to work well. When used with various methods of plotting and dissecting the measurements, data points representing Cepheids and other special stars fall neatly along straight lines, with very little of the “scatter” that would indicate random error.

    “It’s telling us we’re really looking at the real stuff,” Madore said.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 11:51 am on December 19, 2020 Permalink | Reply
    Tags: "A Signal from Proxima Centauri?", Astronomers with the Breakthrough Listen Project have detected radio emissions from the direction of Proxima Centauri., Astronomy, , , , , , The Breakthrough Listen folk are careful not to indulge in any chest beating until the signal is subjected to additional observations., The signal was picked up by the Australian Parkes 210-foot radio telescope., Well it might be aliens. Then again in the tradition of Pogo it might just be us- led astray by our own technology.   

    From SETI Institute: “A Signal from Proxima Centauri?” 



    From SETI Institute

    Dec 19, 2020
    By Seth Shostak, Senior Astronomer

    1
    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia, 414.80m above sea level.

    Well, it might be aliens. Then again, in the tradition of Pogo it might just be us, led astray by our own technology.

    A story in Britain’s Guardian newspaper today (December 18) reports that astronomers with the Breakthrough Listen Project – the comprehensive radio SETI search being run out of the University of California at Berkeley – has detected radio emissions from the direction of Proxima Centauri.

    ____________________________________________________________________________________________________
    Breakthrough Listen Project

    1

    UC Observatories Lick Autmated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA




    GBO radio telescope, Green Bank, West Virginia, USA


    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia


    SKA SARAO Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA.


    Newly added

    CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four Čerenkov Telescopes for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory,Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)


    ____________________________________________________________________________________________________

    That’s the closest star system to us, a mere 4.2 light-years away, and it’s known to be accompanied by at least two planets.

    The signal was picked up by the Parkes 210-foot radio telescope in sheep country about 190 miles inland from Sydney, Australia. Because Proxima Centauri is only visible in the southern sky, you need a “down under” telescope to observe it.

    But does this mean that SETI researchers have finally stumbled upon their holy grail, a radio emission that could only come from a deliberately constructed transmitter on another world? It’s possible, of course. But the Breakthrough Listen folk are careful not to indulge in any chest beating until the signal is subjected to additional observations.

    So, what are the possible implications of this finding? Let us count the ways:

    To begin, the signal apparently varies slightly in frequency, wobbling up and down the radio dial. So it’s not coming from an antenna bolted to the ground here on Earth. That immediately makes it non-terrestrial by definition, but still doesn’t certify it as alien.

    Indeed, it just might be a telemetry signal from an orbiting satellite. The orbital motion of these satellites cause their transmissions to rise and fall in frequency, after all. And while you might think that the chances of accidentally tuning in a satellite are not great, you should think again. There are more than 2,700 functioning satellites buzzing our planet, providing information on the weather, imagery for Google Earth, GPS signals for navigation, and high-resolution photos for the military, just to name a few. This flood of information from hardware a few hundred miles above our heads is obviously important for a high-tech lifestyle, but it jams a lot of the radio spectrum. SETI scientists are trying to find a needle in a pile of pins.

    But if it’s not a satellite signal, what else might it be? It’s possible that the signal is actually coming from something behind Proxima Centauri that just happens to line up with it. There’s an example of this coming your way next week, when Jupiter will seem to be intruding upon Saturn’s personal space as the two planets get close in the evening sky. On December 21, their separation will be only 6 arcmin, or about the width of a dime held at 20 feet. But of course Jupiter and Saturn won’t actually be close. You’d find 500 million miles of uninteresting space behind Jupiter before you encountered the ring thing. They just appear to line up.

    So maybe that’s what’s going on: the signal’s not coming from Proxima Centauri, but from something else far beyond it. Maybe, but that would still be extremely interesting, as natural radio signals – the type produced by quasars, pulsars, and many other members of the cosmic bestiary – are not narrow-band. They’re not confined to a small range of frequencies, and this signal might be.

    Of course, there’s always the possibility that the signal is really, really local. A microwave oven in the break room of the Parkes radio telescope caused considerable consternation five years ago when it produced signals that, at first, suggested that something remarkable was happening in the distant cosmos. In fact, it was just someone heating up lunch.

    So, given even this short laundry list, we see that there are several possible explanations for the signal that are, regrettably, rather prosaic. Yes, as long as we still don’t know, we should continue to consider the alien hypothesis viable. After all, any SETI detection is going to be dicey when we first make it … there will be plenty of calls for restraint intended to pacify the all-too-eager. But it’s reasonable to expect that someday one of these suspicious signals will, indeed, be the sought-after proof of intelligence on another world.

    Caution is often a good idea, but one must be careful not to toss the baby with the bathwater. After all, this baby could change our concept of the cosmos.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    SETI Institute


    About the SETI Institute
    What is life? How does it begin? Are we alone? These are some of the questions we ask in our quest to learn about and share the wonders of the universe. At the SETI Institute we have a passion for discovery and for passing knowledge along as scientific ambassadors.

    The SETI Institute is a 501 (c)(3) nonprofit scientific research institute headquartered in Mountain View, California. We are a key research contractor to NASA and the National Science Foundation (NSF), and we collaborate with industry partners throughout Silicon Valley and beyond.

    Founded in 1984, the SETI Institute employs more than 130 scientists, educators, and administrative staff. Work at the SETI Institute is anchored by three centers: the Carl Sagan Center for the Study of Life in the Universe (research), the Center for Education and the Center for Outreach.

    The SETI Institute welcomes philanthropic support from individuals, private foundations, corporations and other groups to support our education and outreach initiatives, as well as unfunded scientific research and fieldwork.

    A Special Thank You to SETI Institute Partners and Collaborators
    • Campoalto, Chile, NASA Ames Research Center, NASA Headquarters, National Science Foundation, Aerojet Rocketdyne,SRI International

    Frontier Development Lab Partners
    • Breakthrough Prize Foundation, European Space Agency, Google Cloud, IBM, Intel, KBRwyle. Kx Lockheed Martin, NASA Ames Research Center, Nvidia, SpaceResources Luxembourg, XPrize

    In-kind Service Providers
    • Gunderson Dettmer – General legal services, Hello Pilgrim – Website Design and Development Steptoe & Johnson – IP legal services, Danielle Futselaar

    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)

    SETI Institute – 189 Bernardo Ave., Suite 100
    Mountain View, CA 94043
    Phone 650.961.6633 – Fax 650-961-7099
    Privacy PolicyQuestions and Comments

    Also in the hunt, but not a part of the SETI Institute

    SETI@home, a BOINC [Berkeley Open Infrastructure for Network Computing] project originated in the Space Science Lab at UC Berkeley.


    BOINCLarge

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

     
  • richardmitnick 11:14 pm on December 18, 2020 Permalink | Reply
    Tags: "New Exoplanet Research Method Could Uncover Thousands of Habitable Worlds", Astronomy, , , , , , PIE-planetary infrared excess technique   

    From JHU Applied Physics Lab: “New Exoplanet Research Method Could Uncover Thousands of Habitable Worlds” 

    JHUAPL

    Johns Hopkins Applied Physics Lab bloc

    From JHU Applied Physics Lab

    December 18, 2020
    Jeremy Rehm
    240-592-3997
    Jeremy.Rehm@jhuapl.edu

    1
    Artist’s illustration of two Earth-sized planets passing in front of their parent red dwarf star. Transiting planets such as these are one of two typical ways scientists study the atmospheres of exoplanets. Credit: NASA/ESA/STScI/J. de Wit (MIT).

    2
    Graphic of the planetary infrared excess technique, based on a star and non-transiting planet. Starlight is typically brightest at shorter wavelengths in the visible or ultraviolet regions and dimmer in the longer infrared region (0.75–1,000 micrometers), whereas planets are always brightest in the infrared. Scientists can use the shorter-wavelength region as a reference to fit a model of the star by itself and then extrapolate that model to the longer infrared wavelengths. Any light in the infrared region that’s above that expected from the star alone can then be attributed to a non-transiting planet, allowing scientists to deduce characteristics about the planet’s atmosphere and habitability. Because the planet’s light is much dimmer than the star’s, its brightness in this model-based graphic had to be multiplied by 1,000 to make the lines distinguishable. Credit: Johns Hopkins APL.

    How do you find and study the atmosphere of an exoplanet — a planet in another solar system — that, by all current methods, is undetectable?

    The question kept gnawing at Kevin Stevenson, an astrophysicist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. And he wasn’t alone. Many exoplanet researchers, trying to study these distant worlds’ atmospheres, have run into the same question because planetary atmospheres can reveal a lot about a planet, perhaps most importantly about its habitability and whether it’s inhabited. But current methods are limited.

    Studying an exoplanet’s atmosphere requires light, and right now it can be studied only if the planet is large, young and hot enough to produce light that can be directly imaged, or if it passes in front of its star (a transit) or behind its star (a secondary eclipse). Either way allows scientists to distinguish light that’s from the planet and light that’s from its star.

    But large, young and hot planets are usually Jupiter- or Neptune-sized gas giants — not ideal when looking for life. And, from Earth’s vantage, a majority of planets never pass in front of or behind their stars. In fact, for planets around red dwarf stars — which make up 75% of stars in our corner of the Milky Way galaxy — only 2% of potentially habitable exoplanets transit their star, Stevenson said. What if you could see the other 98%?

    Stevenson mulled over the problem for months, spitballing ideas with colleagues at conferences, until slowly, surely, he figured out a way. He dubbed it the planetary infrared excess technique, or PIE, which he wrote about in The Astrophysical Journal Letters earlier this year. And it could be a revolutionary fix-up for exoplanet research.

    “This method would reveal a huge swath of exoplanets that have previously been inaccessible in terms of atmospheric characterization,” Stevenson said, possibly multiplying the number of exoplanets that can be studied by 50 times.

    Rather than depending on a secondary eclipse to determine what light comes from the planet and what comes from the star, PIE relies on two points in wavelength space: one where the planet emits light because of heat and one where it does not. The method takes advantage of the fact that, at wavelengths of light where the planet is relatively bright, the star tends to be dimmer. And at wavelengths where the star is bright, the planet is dimmer.

    Take the Sun and Earth, for example. Although the Sun emits almost every wavelength of light, it most strongly gives off visible light, with a peak around 0.5 micrometers at blue-green light. At longer red and infrared wavelengths, however, the Sun’s emission tapers. But much cooler bodies, like planets, often peak in this region, including Earth, which peaks at 10 micrometers.

    Stevenson’s idea is to simultaneously collect wavelengths of light in a sweet spot from 1 to 20 micrometers, where scientists know all planets will emit light. Then they can model the star’s and the planet’s spectra for comparison.

    “We can use the shorter, bluer wavelength range as our reference point, which is where we could fit models to the star,” Stevenson said. “Then we could extrapolate those models to the longer, redder wavelengths. Any excess infrared light in that range we would attribute to the planet. That’s how, in theory, we could measure the brightness temperature of a planet that’s not transiting.”

    PIE will be the primary observational focus of an international team of scientists Stevenson will lead for the next three years, as they further develop the idea through NASA’s new Interdisciplinary Consortia for Astrobiology Research (ICAR), announced last month.

    The concept of infrared excess is used elsewhere in astrophysics research, such as distinguishing two stars in a binary star system. When the stars have different temperatures, their peak wavelengths differ, allowing each star to be distinguished by measuring the light it emits.

    “This method pushes that idea to an extreme,” Stevenson said.

    That extremity creates a few drawbacks. Because planets don’t emit much light, a planet’s peak signal will be very small relative to the star.

    As a result, Stevenson plans to look for planets around M-dwarf stars, such as TRAPPIST-1, where seven planets (including three potentially habitable worlds) were discovered in 2017.

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA.

    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile, at an altitude of 2400 metres.

    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    M-dwarf stars are relatively small, weighing from 7.5% to 50% the mass of the Sun. That makes them thousands of degrees cooler and much dimmer, so the light of a planet won’t be washed out.

    People have talked about searching for life around M-dwarf stars because of this advantage, Stevenson said. “You just have more signal to work with from the planet.”

    The ICAR team Stevenson will lead plans to hone the PIE technique and test it on these M-dwarf stars by leveraging the infrared light-detecting capabilities of future space telescopes, particularly NASA’s James Webb Space Telescope (JWST) and the conceptual Origins Space Telescope (OST).

    NASA James Webb Space Telescope annotated.

    3
    Origins Space Telescope (OST). https://spie.org/news/origins-space-telescope-wants-to-answer-the-big-questions

    Using models to simulate JWST’s capability to detect near-infrared wavelengths (0.8–2.5 micrometers), the team can determine the validity of the PIE technique and establish the wavelength range, power and precision necessary for its successful implementation.

    Stevenson expects JWST’s narrow reach into the infrared will limit it to studying non-transiting warm Neptunes and hot Jupiters, an ideal starting place to test the idea, he said. From there, they can model OST’s capability to look into the mid-infrared (1.3–3.0 micrometers), which could look at cooler, more Earth-like planets where life might be found.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    JHUAPL campus.

    Founded on March 10, 1942—just three months after the United States entered World War II— the JHU Applied Physics Lab -was created as part of a federal government effort to mobilize scientific resources to address wartime challenges.

    APL was assigned the task of finding a more effective way for ships to defend themselves against enemy air attacks. The Laboratory designed, built, and tested a radar proximity fuze (known as the VT fuze) that significantly increased the effectiveness of anti-aircraft shells in the Pacific—and, later, ground artillery during the invasion of Europe. The product of the Laboratory’s intense development effort was later judged to be, along with the atomic bomb and radar, one of the three most valuable technology developments of the war.

    On the basis of that successful collaboration, the government, The Johns Hopkins University, and APL made a commitment to continue their strategic relationship. The Laboratory rapidly became a major contributor to advances in guided missiles and submarine technologies. Today, more than seven decades later, the Laboratory’s numerous and diverse achievements continue to strengthen our nation.

    APL continues to relentlessly pursue the mission it has followed since its first day: to make critical contributions to critical challenges for our nation.

    Johns Hopkins Unversity campus.

    Johns Hopkins University opened in 1876, with the inauguration of its first president, Daniel Coit Gilman. “What are we aiming at?” Gilman asked in his installation address. “The encouragement of research … and the advancement of individual scholars, who by their excellence will advance the sciences they pursue, and the society where they dwell.”

    The mission laid out by Gilman remains the university’s mission today, summed up in a simple but powerful restatement of Gilman’s own words: “Knowledge for the world.”

    What Gilman created was a research university, dedicated to advancing both students’ knowledge and the state of human knowledge through research and scholarship. Gilman believed that teaching and research are interdependent, that success in one depends on success in the other. A modern university, he believed, must do both well. The realization of Gilman’s philosophy at Johns Hopkins, and at other institutions that later attracted Johns Hopkins-trained scholars, revolutionized higher education in America, leading to the research university system as it exists today.

     
  • richardmitnick 10:32 pm on December 18, 2020 Permalink | Reply
    Tags: "Study Confirms Dark Coating Can Reduce Satellite Reflectivity", , Astronomy, , , , National Astronomical Observatory of Japan [国立天文台; kokuritsu tenmondai](JP)   

    From National Astronomical Observatory of Japan [国立天文台; kokuritsu tenmondai](JP): “Study Confirms Dark Coating Can Reduce Satellite Reflectivity” 

    From National Astronomical Observatory of Japan [国立天文; kokuritsu tenmondai] (JP)

    December 8, 2020

    1
    The trail of a Starlink satellite (the line from upper right to lower left) captured by the Murikabushi Telescope on April 10, 2020. Credit: NAOJ.

    Observations conducted by the Murikabushi Telescope of Ishigakijima Astronomical Observatory confirmed that dark coating can reduce satellite reflectivity by half.

    2
    Murikabushi Telescope of Ishigakijima Astronomical Observatory (JP)

    There are concerns that numerous artificial satellites in orbit could impair astronomical observations, but these findings may help alleviate such conditions.

    Today’s growing demand for space-based services has spawned a wave of satellite constellation projects which operate numerous artificial satellites in orbit. Since these satellites can shine by reflecting sunlight, the astronomy community has raised concerns about their potential impact on astronomical observations. In January 2020, SpaceX launched “DarkSat,” an experimental satellite with an anti-reflective coating, and asked astronomers to assess how much this coating can reduce the satellite reflectivity. Brightness measurements of artificial satellites have already been conducted, but until now, there was no verification that a dark coating actually achieves the expected reflectivity reduction.

    The Murikabushi Telescope of Ishigakijima Astronomical Observatory can observe celestial objects simultaneously in three different wavelengths (colors). Comparing multicolor data obtained under the same conditions provides more accurate insight into how much the coating can reduce the satellite brightness. Observations conducted from April to June 2020 revealed for the first time in the world that artificial satellites, whether coated or not, are more visible at longer wavelengths, and that the black coating can halve the level of surface reflectivity of satellites. Such surface treatment is expected to reduce the negative impacts on astronomical observations. Further measures will continue to be implemented to pave the way for peaceful coexistence between space industries and astronomy.

    These results appeared in The Astrophysical Journal on December 7, 2020.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The National Astronomical Observatory of Japan (NAOJ)[国立天文台, kokuritsu tenmondai] (JP) is an astronomical research organisation comprising several facilities in Japan, as well as an observatory in Hawaii. It was established in 1988 as an amalgamation of three existing research organizations – the Tokyo Astronomical Observatory of the University of Tokyo, International Latitude Observatory of Mizusawa, and a part of Research Institute of Atmospherics of Nagoya University.

    In the 2004 reform of national research organizations, NAOJ became a division of the National Institutes of Natural Sciences.

    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA,4,207 m (13,802 ft) above sea level


    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array
    sft
    Solar Flare Telescope

    Nobeyama Millimeter Array Radioheliograph, located near Minamimaki, Nagano at an elevation of 1350m

    Mizusawa VERA Observatory

    Okayama Astrophysical Observatory

    NAOJ Kyoto U 3.8m SEMEI Telescope

     
  • richardmitnick 10:01 pm on December 18, 2020 Permalink | Reply
    Tags: "Abell 2261- On the Hunt for a Missing Giant Black Hole", Astronomy, , , , ,   

    From NASA Chandra: “Abell 2261- On the Hunt for a Missing Giant Black Hole” 

    NASA Chandra Banner

    NASA Chandra X-ray Space Telescope

    From NASA Chandra

    December 17, 2020

    1
    Composite

    2
    X-ray

    3
    Optical/Infrared

    Credit X-ray: NASA/CXC/Univ of Michigan/K. Gültekin; Optical: NASA/STScI and NAOJ/Subaru; Infrared: NSF/NOAO/KPNO.

    Astronomers are searching for signs of a supermassive black hole in the galaxy cluster Abell 2261.

    Nearly all large galaxies contain central black holes, and the galaxy in the middle of Abell 2261 is expected to contain a particularly massive one.

    Scientists think this galaxy underwent a merger with another galaxy in the past, which could have caused a newly formed larger black hole to be ejected.

    Despite careful searches with Chandra and other telescopes, astronomers do not yet know what happened to this giant black hole.

    The mystery surrounding the whereabouts of a supermassive black hole has deepened.

    Despite searching with NASA’s Chandra X-ray Observatory and Hubble Space Telescope, astronomers have no evidence that a distant black hole estimated to weigh between 3 billion and 100 billion times the mass of the Sun is anywhere to be found.

    This missing black hole should be in the enormous galaxy in the center of the galaxy cluster Abell 2261, which is located about 2.7 billion light years from Earth. This composite image of Abell 2261 contains optical data from Hubble and the Subaru Telescope showing galaxies in the cluster and in the background, and Chandra X-ray data showing hot gas (colored pink) pervading the cluster. The middle of the image shows the large elliptical galaxy in the center of the cluster.

    Nearly every large galaxy in the Universe contains a supermassive black hole in their center, with a mass that is millions or billions of times that of the Sun. Since the mass of a central black hole usually tracks with the mass of the galaxy itself, astronomers expect the galaxy in the center of Abell 2261 to contain a supermassive black hole that rivals the heft of some of the largest known black holes in the Universe.

    Using Chandra data obtained in 1999 and 2004 astronomers had already searched the center of Abell 2261’s large central galaxy for signs of a supermassive black hole. They looked for material that has been superheated as it fell towards the black hole and produced X-rays, but did not detect such a source.

    Now, with new, longer Chandra observations obtained in 2018, a team led by Kayhan Gultekin from the University of Michigan in Ann Arbor conducted a deeper search for the black hole in the center of the galaxy. They also considered an alternative explanation, in which the black hole was ejected from the host galaxy’s center. This violent event may have resulted from two galaxies merging to form the observed galaxy, accompanied by the central black hole in each galaxy merging to form one enormous black hole.

    When black holes merge, they produce ripples in spacetime called gravitational waves. If the huge amount of gravitational waves generated by such an event were stronger in one direction than another, the theory predicts that the new, even more massive black hole would have been sent careening away from the center of the galaxy in the opposite direction. This is called a recoiling black hole.

    Astronomers have not found definitive evidence for recoiling black holes and it is not known whether supermassive black holes even get close enough to each other to produce gravitational waves and merge; so far, astronomers have only verified the mergers of much smaller black holes. The detection of recoiling supermassive black holes would embolden scientists using and developing observatories to look for gravitational waves from merging supermassive black holes.

    The galaxy at the center of Abell 2261 is an excellent cluster to search for a recoiling black hole because there are two indirect signs that a merger between two massive black holes might have taken place. First, data from the Hubble and Subaru optical observations reveal a galactic core — the central region where the number of stars in the galaxy in a given patch of the galaxy is at or close to the maximum value — that is much larger than expected for a galaxy of its size. The second sign is that the densest concentration of stars in the galaxy is over 2,000 light years away from the center of the galaxy, which is strikingly distant.

    These features were first identified by Marc Postman from Space Telescope Science Institute (STScI) and collaborators in their earlier Hubble and Subaru images, and led them to suggest the idea of a merged black hole in Abell 2261.

    NASA/ESA Hubble Telescope.

    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA,4,207 m (13,802 ft) above sea level.

    During a merger, the supermassive black hole in each galaxy sinks toward the center of the newly coalesced galaxy.

    Artist’s iconic conception of two merging black holes similar to those detected by LIGO Credit LIGO-Caltech/MIT/Sonoma State /Aurore Simonnet.

    If they become bound to each other by gravity and their orbit begins to shrink, the black holes are expected to interact with surrounding stars and eject them from the center of the galaxy. This would explain Abell 2261’s large core. The off-center concentration of stars may also have been caused by a violent event such as the merger of two supermassive black holes and subsequent recoil of single, larger black hole that results.

    Even though there are clues that a black hole merger took place, neither Chandra nor Hubble data showed evidence for the black hole itself. Gultekin and most of his co-authors, led by Sarah Burke-Spolaor from West Virginia University, had previously used Hubble to look for a clump of stars that might have been carried off by a recoiling black hole. They studied three clumps near the center of the galaxy, and examined whether the motions of stars in these clumps are high enough to suggest they contain a ten billion solar mass black hole. No clear evidence for a black hole was found in two of the clumps and the stars in the other one were too faint to produce useful conclusions.

    They also previously studied observations of Abell 2261 with the NSF’s Karl G. Jansky Very Large Array.

    NRAO Karl G Jansky Very Large Array, located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~50 miles (80 km) west of Socorro. The VLA comprises twenty-eight 25-meter radio telescopes.

    Radio emission detected near the center of the galaxy showed evidence that supermassive black hole activity had occurred there 50 million years ago, but does not indicate that the center of the galaxy currently contains such a black hole.

    4
    Credit: NASA/CXC, NASA/STScI, NAOJ/Subaru, NSF/NRAO/VLA

    They then turned to Chandra to look for material that had been superheated and produced X-rays as it fell towards the black hole. While the Chandra data did reveal that the densest hot gas was not in the center of the galaxy, they did not reveal any possible X-ray signatures of a growing supermassive black hole — no X-ray source was found in the center of the cluster, or in any of the clumps of stars, or at the site of the radio emission.

    The authors concluded that either there is no black hole at any of these locations, or that it is pulling material in too slowly to produce a detectable X-ray signal.

    The mystery of this gigantic black hole’s location therefore continues. Although the search was unsuccessful, hope remains for astronomers looking for this supermassive black hole in the future. Once launched, the James Webb Space Telescope may be able to reveal the presence of a supermassive black hole in the center of the galaxy or one of the clumps of stars. If Webb is unable to find the black hole, then the best explanation is that the black hole has recoiled well out of the center of the galaxy.

    A paper describing these results has been accepted for publication in a journal of the American Astronomical Society, and is also available online at https://arxiv.org/abs/2010.13980 [Chandra Observations of Abell 2261 Brightest Cluster Galaxy, a Candidate Host to a Recoiling Black Hole]. Gultekin’s co-authors are Sarah Burke-Spolaor; Tod R. Lauer (National Optical Infrared Astronomy Research Laboratory, Tucson, Arizona); T. Joseph W. Lazio and Leonidas A. Moustakas (Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California); and Patrick Ogle and Marc Postman (Space Telescope Science Institute, Baltimore, Maryland).


    Quick Look: On the Hunt for a Missing Giant Black Hole.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

     
  • richardmitnick 4:10 pm on December 18, 2020 Permalink | Reply
    Tags: "A Rosetta Stone for Planet Formation", Astronomy, , , , , The scientists for the first time in a transition disk mapped the gas density and the gas-to-dust ratio finding that it was less than expected.,   

    From Harvard-Smithsonian Center for Astrophysics: “A Rosetta Stone for Planet Formation” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    1
    This image shows the disc around the young star AB Aurigae in polarized near-infrared light as seen with the European Very Large Telescope’s SPHERE instrument. Measurements of the molecular components of the disk at millimeter wavelengths reveal several unexpected properties including a warmer temperature, more dust, and a deficiency of sulfur. Credit: ESO/Boccaletti et al.

    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT UT3, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.

    Planets are formed from the disk of gas and dust around a star, but the mechanisms for doing so are imperfectly understood. Gas is the key driver in the dynamical evolution of planets, for example, because it is the dominant component of the disk (by mass). The timescale over which the gas dissipates sets the timescale for planet formation, yet its distribution in disks is just starting to be carefully measured. Similarly, the chemical composition of the gas determines the composition of the future planets and their atmospheres, but even after decades of studying protoplanetary disks, their chemical compositions are poorly constrained; even the gas-to-dust ratios are largely unknown.

    The detailed characterizations of individual sources provide insights into the physical and chemical nature of protoplanetary disks. The star AB Aurigae is a widely studied system hosting a young transitional disk, a disk with gaps suggestive of clearing by newly forming planets. Located 536 light-years (plus-or-minus 1%) from the Sun, it is close enough to be an excellent candidate in which to study the spatial distribution of gas and dust in detail. CfA astronomer Romane Le Gal was a member of a team that used the NOrthern Extended Millimeter Array (NOEMA) to observe the AB Aur gas disk at high spatial resolution in the emission lines of CO, H2CO, HCN, and SO; combined with archival results, their dataset includes a total of seventeen different spectral features.

    IRAM NOEMA in the French Alps on the wide and isolated Plateau de Bure at an elevation of 2550 meters, the telescope currently consists of ten antennas, each 15 meters in diameter.interferometer, Located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters.

    The scientists, for the first time in a transition disk, mapped the gas density and the gas-to-dust ratio, finding that it was less than expected – half of the interstellar medium value or even in some places as much as four times smaller. Different molecules were seen tracing different regions of the disk, for instance the envelope or the surface. The team measured the average disk temperature to be about 39K, warmer than estimated in other disks. Not least, their chemical analysis determined the relative abundances of the chemicals and found (depending on some assumptions) that sulfur is strongly depleted compared to the solar system value. The new paper’s primary conclusion, that the planet-forming disk around this massive young star is significantly different from expectations, highlights the importance of making such detailed observations of disks around massive stars.

    Science paper:
    AB Aur, a Rosetta Stone for Studies of Planet Formation I. Chemical study of a planet-forming disk
    Astronomy & Astrophysics

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 3:45 pm on December 18, 2020 Permalink | Reply
    Tags: Astronomy, , , Bright millisecond pulsar J0437−4715, , Instituto Argentino de Radioastronomía (IAR)(AR), , , Scientists from RIT and IAR just completed a yearlong pulsar timing study using two upgraded radio telescopes in Argentina that previously lay unused for 15 years.   

    From Rochester Institute of Technology: “Scientists complete yearlong pulsar timing study after reviving long-dormant radio telescopes” 

    From Rochester Institute of Technology

    December 16, 2020
    Luke Auburn
    luke.auburn@rit.edu

    RIT and IAR scientists outline the findings in a new paper in The Astrophysical Journal

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    Scientists from RIT and IAR just completed a yearlong pulsar timing study using two upgraded radio telescopes in Argentina that previously lay unused for 15 years.

    The Argentine Institute of Radio astronomy (IAR) is equipped with two single-dish 30 m radio antennas capable of performing daily observations of pulsars and radio transients in the southern hemisphere at 1.4 GHz.

    While the scientific community grapples with the loss of the Arecibo radio telescope, astronomers who recently revived a long-dormant radio telescope array in Argentina hope it can help modestly compensate for the work Arecibo did in pulsar timing. Last year, scientists at Rochester Institute of Technology and the Instituto Argentino de Radioastronomía (IAR)(AR) began a pulsar timing study using two upgraded radio telescopes in Argentina that previously lay unused for 15 years.

    The scientists are releasing observations from the first year in a new study to be published in The Astrophysical Journal. Over the course of the year, they studied the bright millisecond pulsar J0437−4715. Pulsars are rapidly rotating neutron stars with intense magnetic fields that regularly emit radio waves, which scientists study to look for gravitational waves caused by the mergers of supermassive black holes.

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    Women in STEM – Dame Susan Jocelyn Bell Burnell Discovered pulsars.

    Dame Susan Jocelyn Bell Burnell discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Dame Susan Jocelyn Bell Burnell at work on first plusar chart 1967 pictured working at the Four Acre Array in 1967. Image courtesy of Mullard Radio Astronomy Observatory.


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    Professor Carlos Lousto, a member of RIT’s School of Mathematical Sciences and the Center for Computational Relativity and Gravitation (CCRG), said the first year of observations proved to be very accurate and provided some bounds to gravitational waves, which can help increase the sensitivity of existing pulsar timing arrays. He said that over the course of the next year they plan to study a younger, less stable pulsar that is more prone to glitches. He hopes to leverage machine learning and artificial intelligence to better understand the individual pulses emitted by pulsars and predict when glitches occur.

    “Every second of observation has 11 pulses and we have thousands of hours of observation, so it is a lot of data,” said Lousto. “What we hope to accomplish is analogous to monitoring the heartbeat one by one to learn to predict when someone is going to have a heart attack.”

    Lousto said Ph.D. students from RIT’s programs in astrophysical sciences and technology, mathematical modeling, and computer science are at the forefront of the analysis. RIT has a remote station called the Pulsar Monitoring in Argentina Data Enabling Network (PuMA-DEN) to control the radio telescopes and store the data collected. He said the opportunities presented by the collaboration are important for the students from the College of Science and Golisano College of Computing and Information Sciences because “the careers in astronomy are changing very quickly, so you have to keep up with new technology and new ideas.”

    In the longer term, Lousto said RIT and IAR are seeking out other radio telescopes that can be upgraded for pulsar timing studies, further filling the gap left behind by Arecibo. RIT and IAR’s observations seek to contribute to the larger efforts of the North American Nanohertz Observatory for Gravitation Waves (NANOGrav) and the International Pulsar Timing Array, an collaboration of scientists working to detect and study the impact of low frequency gravitational waves passing between the pulsars and the Earth.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Rochester Institute of Technology (RIT) is a private doctoral university within the town of Henrietta in the Rochester, New York metropolitan area.

    RIT is composed of nine academic colleges, including National Technical Institute for the Deaf. The Institute is one of only a small number of engineering institutes in the State of New York, including New York Institute of Technology, SUNY Polytechnic Institute, and Rensselaer Polytechnic Institute. It is most widely known for its fine arts, computing, engineering, and imaging science programs; several fine arts programs routinely rank in the national “Top 10” according to US News & World Report.

    The Institute as it is known today began as a result of an 1891 merger between Rochester Athenæum, a literary society founded in 1829 by Colonel Nathaniel Rochester and associates, and Mechanics Institute, a Rochester institute of practical technical training for local residents founded in 1885 by a consortium of local businessmen including Captain Henry Lomb, co-founder of Bausch & Lomb. The name of the merged institution at the time was called Rochester Athenæum and Mechanics Institute (RAMI). In 1944, the school changed its name to Rochester Institute of Technology and it became a full-fledged research university.

     
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