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  • richardmitnick 5:03 pm on January 21, 2021 Permalink | Reply
    Tags: "Quasars in the Early Universe", Astronomers have used Chandra to study the X-ray emission from fifteen quasars dating from an era only about one billion years after the big bang., , , , , Harvard Smithsonian Center for Astrophysics, Quasars are perhaps the best-known kinds of active galactic nuclei (AGN)., The effort is to understand how the supermassive black holes in this early epoch evolved.   

    From Harvard-Smithsonian Center for Astrophysics: “Quasars in the Early Universe” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    January 15, 2021

    1
    Astronomers have used Chandra to study the X-ray emission from fifteen quasars dating from an era only about one billion years after the big bang, in an effort to understand how the supermassive black holes in this early epoch evolved.

    NASA Chandra X-ray Space Telescope.

    Quasars are perhaps the best-known kinds of active galactic nuclei (AGN), galaxies whose central supermassive black holes are luminous, sometimes brighter than the rest of the galaxy. In an AGN, material accretes onto a surrounding torus of gas and dust, heating it to thousands of degrees and prompting the ejection of jets of charged particles. In the case of quasars, our viewing angle is such that these dusty tori do not obscure the light and the bright core of a quasar dominates the galaxy’s emission. The most distant known quasar dates from the era only about 700 million years after the big bang, with dozens more known dating from the first few billion years.

    One outstanding puzzle is how the supermassive black holes in these young quasars could have formed in the short time available since the universe existed. The very hot material and the fast-moving particles produce X-ray emission, especially from the inner region of the accretion. Although X-ray emission is difficult to detect from such distant objects, CfA astronomers Bradford Snios, Aneta Siemiginowska, Malgosia Sobolewska, Vinay Kashyap, and Dan Schwarz led a team that has obtained X-ray spectra from fifteen quasars that date from roughly a billion years after the big bang and that individually span a period of about one hundred and fifty million years. The astronomers used the Chandra X-ray Observatory to look at targets selected from a catalog of quasars whose characters and distances were already known from their radio emission and optical emission. In particular, the team selected quasars whose radio emission appears (based on its spectral shape) to arise from a small volume within the galaxy.

    The astronomers analyzed the X-ray emission from these quasars with other data to infer how these objects and their emission may have evolved in comparison with quasars in the nearby universe. The most significant conclusion from this ongoing work is that there does not appear to be any clear evolutionary trends during this era. They also identified several outlier quasars, one of them named J1606+3124 with an extremely high gas density along the line-of-sight, only the fourth known quasar in the early universe known to have as much dense material.

    Science paper:
    X-ray Properties of Young Radio Quasars at z > 4:5
    The Astrophysical Journal

    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 5:33 pm on January 10, 2021 Permalink | Reply
    Tags: "Coronal Holes During the Solar Maximum", , , , , Coronal holes, , Harvard Smithsonian Center for Astrophysics, , ,   

    From Harvard-Smithsonian Center for Astrophysics: “Coronal Holes During the Solar Maximum” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    Sunspots were first seen by Galileo, and in the eighteenth century Rudolf Wolf concluded from his study of previous observations that there was a roughly eleven-year solar cycle of activity. In 1919 the astronomer George Ellery Hale found a new solar periodicity, the twenty-two year solar magnetic cycle which is composed of two eleven-year cycles and today is referred to as the Hale cycle. The eleven-year cycle is a complex dynamo process in which the Sun’s twisted magnetic fields flip to the opposite direction as the result of the combination of the Sun’s differential rotation and the convection in its atmosphere. Then, after a second cycle, the original polarity is recovered. The cycle is characterized by periodic changes in solar activity such as the number of sunspots and active regions (ensembles of looped magnetic structures); during the period of maximum activity the number of sunspots reaches a maximum. The number of coronal holes provides another measure of activity, a coronal hole being a darker appearing region of colder gas on the Sun’s surface. During maximum activity, coronal holes are found at low latitudes of the Sun with fewer of them at the polar regions.

    1
    An ultraviolet image of the Sun showing a coronal hole – a dark region, seen here at the north pole of the Sun with NASA’s Solar Dynamics Observatory. Coronal holes are regions where the weakened magnetic field allows for a stronger solar wind to emerge.

    Solar winds-Sun’s coronal holes release solar winds towards Earth. National Geophysical Data Cantre.

    Astronomers have found correlations between coronal holes near the Sun’s equator and the eleven and twenty-two year solar cycles. Credit: NASA/SDO.

    NASA/SDO.

    Energetic events on the Sun like eruptions, flares, and coronal mass ejections peak at or near times of solar maximum.

    Solar flare. Credit NASA/ SDO.

    Coronal Mass Ejection. Credit ESA.

    At the same time some structures in the magnetic field weaken to zero strength and then increase but with the opposite sign. A particularly powerful solar wind can escape during these periods of weak magnetic fields and its charged particles can then travel into space and towards the Earth.

    Coronal holes are key structures that indicate these weakened fields. CfA astronomers Nishu Karna, Steven Saar, and Ed DeLuca and a team of colleagues performed a statistical study of the coronal holes near the equatorial region, and of active regions, during the maximum phase of the last four solar cycles spanning the years from 1979-2015.

    The scientists found a strong negative correlation between the numbers of equatorial coronal holes and active regions as well as statistically significant differences in the properties of the two eleven-year cycles of the Hale cycle. For example, they examined the changing distances (“pairings”) between equatorial coronal holes and active regions and find more of the close pairings during the peak of activity in one half of the Hale cycle…but not in the other. Most significantly, during these active times the solar wind flow and wind pressure also increase significantly. The results lead to important insights into how solar activity impacts the Earth and highlight important processes that are still not understood like the different behaviors of the two halfs of the Hale cycle.

    Science paper:
    A Study of Equatorial Coronal Holes during the Maximum Phase of Four Solar Cycles
    The Astrophysical Journal

    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 9:36 am on November 23, 2020 Permalink | Reply
    Tags: "Growing Interest in Moon Resources Could Cause Tension Scientists Find", Harvard Smithsonian Center for Astrophysics, Lunar reconnaissance   

    From Harvard-Smithsonian Center for Astrophysics: “Growing Interest in Moon Resources Could Cause Tension, Scientists Find” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    November 23, 2020

    Amy Oliver
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    Fred Lawrence Whipple Observatory
    520-879-4406
    amy.oliver@cfa.harvard.edu

    1
    Taken by NASA’s Lunar Reconnaissance Orbiter, this image of the moon is part of the collection of the highest resolution, near-global topographic maps of the moon ever created. Overlaid on this image are some of the hotspots identified for cosmology telescopes on the moon; few ideal locations for these telescopes exist on the moon, as others conflict with the radio quiet zone. Credit: NASA/Goddard Space Flight Center/DLR (DE)/ASU; Overlay: M. Elvis, A. Krosilowski, T. Milligan.

    NASA/Lunar Reconnaissance Orbiter

    2
    Lunar cold traps located at the South Pole of the moon, are critical to all moon-based operations because they contain frozen water molecules. Water is required for all moon-based operations because it is needed to grow food, and to break down into oxygen for breathing and hydrogen for fuel. The four white-circled regions in this image contain the coldest terrain with average annual near-surface temperatures of 25-50 K. They are about 50 km across. Credit: David Paige, reproduced with permission.

    An international team of scientists led by the Center for Astrophysics | Harvard & Smithsonian, has identified a problem with the growing interest in extractable resources on the moon: there aren’t enough of them to go around. With no international policies or agreements to decide “who gets what from where,” scientists believe tensions, overcrowding, and quick exhaustion of resources to be one possible future for moon mining projects. The paper published today in the Philosophical Transactions of the Royal Society A.

    “A lot of people think of space as a place of peace and harmony between nations. The problem is there’s no law to regulate who gets to use the resources, and there are a significant number of space agencies and others in the private sector that aim to land on the moon within the next five years,” said Martin Elvis, astronomer at the Center for Astrophysics | Harvard & Smithsonian and the lead author on the paper. “We looked at all the maps of the Moon we could find and found that not very many places had resources of interest, and those that did were very small. That creates a lot of room for conflict over certain resources.”

    Resources like water and iron are important because they will enable future research to be conducted on, and launched from, the moon. “You don’t want to bring resources for mission support from Earth, you’d much rather get them from the Moon. Iron is important if you want to build anything on the moon; it would be absurdly expensive to transport iron to the moon,” said Elvis. “You need water to survive; you need it to grow food—you don’t bring your salad with you from Earth—and to split into oxygen to breathe and hydrogen for fuel.”

    Interest in the moon as a location for extracting resources isn’t new. An extensive body of research dating back to the Apollo program has explored the availability of resources such as helium, water, and iron, with more recent research focusing on continuous access to solar power, cold traps and frozen water deposits, and even volatiles that may exist in shaded areas on the surface of the moon. Tony Milligan, a Senior Researcher with the Cosmological Visionaries project at King’s College London, and a co-author on the paper said, “Since lunar rock samples returned by the Apollo program indicated the presence of Helium-3, the moon has been one of several strategic resources which have been targeted.”

    Although some treaties do exist, like the 1967 Outer Space Treaty—prohibiting national appropriation—and the 2020 Artemis Accords—reaffirming the duty to coordinate and notify—neither is meant for robust protection. Much of the discussion surrounding the moon, and including current and potential policy for governing missions to the satellite, have centered on scientific versus commercial activity, and who should be allowed to tap into the resources locked away in, and on, the moon. According to Milligan, it’s a very 20th century debate, and doesn’t tackle the actual problem. “The biggest problem is that everyone is targeting the same sites and resources: states, private companies, everyone. But they are limited sites and resources. We don’t have a second moon to move on to. This is all we have to work with.” Alanna Krolikowski, assistant professor of science and technology policy at Missouri University of Science and Technology (Missouri S&T) and a co-author on the paper, added that a framework for success already exists and, paired with good old-fashioned business sense, may set policy on the right path. “While a comprehensive international legal regime to manage space resources remains a distant prospect, important conceptual foundations already exist and we can start implementing, or at least deliberating, concrete, local measures to address anticipated problems at specific sites today,” said Krolikowski. “The likely first step will be convening a community of prospective users, made up of those who will be active at a given site within the next decade or so. Their first order of business should be identifying worst-case outcomes, the most pernicious forms of crowding and interference, that they seek to avoid at each site. Loss aversion tends to motivate actors.”

    There is still a risk that resource locations will turn out to be more scant than currently believed, and scientists want to go back and get a clearer picture of resource availability before anyone starts digging, drilling, or collecting. “We need to go back and map resource hot spots in better resolution. Right now, we only have a few miles at best. If the resources are all contained in a smaller area, the problem will only get worse,” said Elvis. “If we can map the smallest spaces, that will inform policymaking, allow for info-sharing and help everyone to play nice together so we can avoid conflict.”

    While more research on these lunar hot spots is needed to inform policy, the framework for possible solutions to potential crowding are already in view. “Examples of analogs on Earth point to mechanisms for managing these challenges. Common-pool resources on Earth, resources over which no single act can claim jurisdiction or ownership, offer insights to glean. Some of these are global in scale, like the high seas, while other are local like fish stocks or lakes to which several small communities share access,” said Krolikowski, adding that one of the first challenges for policymakers will be to characterize the resources at stake at each individual site. “Are these resources, say, areas of real estate at the high-value Peaks of Eternal Light, where the sun shines almost continuously, or are they units of energy to be generated from solar panels installed there? At what level can they can realistically be exploited? How should the benefits from those activities be distributed? Developing agreement on those questions is a likely precondition to the successful coordination of activities at these uniquely attractive lunar sites.”

    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 5:43 pm on September 17, 2020 Permalink | Reply
    Tags: "Astronomers Solve Mystery of How Planetary Nebulae Are Shaped", , Astronomers focused their observations on stellar winds—particle flows—around cool red giant stars also known as asymptotic giant branch (AGB) stars.stars., , , , , Following extensive observations of stellar winds around cool evolved stars scientists have figured out how planetary nebulae get their mesmerizing shapes., Harvard Smithsonian Center for Astrophysics, , , The winds observed exhibit various shapes that are similar to planetary nebulae.   

    From Harvard-Smithsonian Center for Astrophysics: “Astronomers Solve Mystery of How Planetary Nebulae Are Shaped” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    September 17, 2020
    Amy Oliver
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    Fred Lawrence Whipple Observatory
    520-879-4406
    amy.oliver@cfa.harvard.edu

    1
    Gallery of stellar winds around cool aging stars, showing a variety of morphologies, including disks, cones, and spirals. The blue color represents material that is coming towards you, red ismaterial that is moving away from you. Image 8, in particular, shows the stellar wind of R Aquilae, which resembles the structure of rose petals. Credit: L. Decin, ESO/ALMA.

    Following extensive observations of stellar winds around cool evolved stars scientists have figured out how planetary nebulae get their mesmerizing shapes. The findings, published in Science, contradict common consensus, and show that not only are stellar winds aspherical, but they also share similarities with planetary nebulae.

    An international team of astronomers focused their observations on stellar winds—particle flows—around cool red giant stars, also known as asymptotic giant branch (AGB) stars. “AGB stars are cool luminous evolved stars that are in the last stages of evolution just before turning into a planetary nebula,” said Carl Gottlieb, an astronomer at the Center for Astrophysics | Harvard & Smithsonian, and a co-author on the paper. “Through their winds, AGB stars contribute about 85% of the gas and 35% of the dust from stellar sources to the Galactic Interstellar Medium and are the dominant suppliers of pristine building blocks of interstellar material from which planets are ultimately formed.”

    Despite being of major interest to astronomers, a large, detailed collection of observational data for the stellar winds surrounding AGB stars—each made using the exact same method—was lacking prior to the study, which resulted in a long-standing scientific misconception: that stellar winds have an overall spherical symmetry. “The lack of such detailed observational data caused us to initially assume that the stellar winds have an overall spherical geometry, much like the stars they surround,” said Gottlieb. “Our new observational data shapes a much different story of individual stars, how they live, and how they die. We now have an unprecedented view of how stars like our Sun will evolve during the last stages of their evolution.”

    Observations with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile revealed something strange: the shape of the stellar winds didn’t conform with scientific consensus.

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

    “We noticed these winds are anything but round,” said Professor Leen Decin of KU Leuven University in Belgium, and the lead author on the paper. “Some of them are actually quite similar to planetary nebulae.” The new findings may have a significant impact on calculations of galactic and stellar evolution, most pointedly for the evolution of Sun-like stars. “Our findings change a lot,” said Decin. “Since the complexity of stellar winds was not accounted for in the past, any previous estimate of the mass-loss rate of old stars could be wrong by up to a factor of 10.”

    The observations revealed many different shapes, further connecting stellar wind formation to that of planetary nebulae. “The winds we observed exhibit various shapes that are similar to planetary nebulae,” said Gottlieb. “Some are disk-like, while others are shaped like eyes, spiral structures, and even arcs.”

    Astronomers quickly realized that the shapes weren’t formed randomly, and that companions—low-mass stars and heavy planets—in the vicinity of the AGB stars were influencing the shapes and patterns. “Just like a spoon that you stir in a cup of coffee with some milk can create a spiral pattern, the companion sucks material towards it as it revolves around the star and shapes the stellar wind,” said Decin. “All of our observations can be explained by the fact that the stars have a companion.”

    In addition, the study provides a strong foundation for understanding Sun-like stars and the future of the Sun itself. “In about five billion years, the Sun will become more luminous,” said Gottlieb. “Its radius will expand to a length that is comparable to the current distance between the Sun and Earth, and it will enter the AGB phase.” Decin added, “Jupiter or even Saturn—because they have such a big mass—are going to influence whether the Sun spends its last millennia at the heart of a spiral, a butterfly or any of the other entrancing shapes we see in planetary nebulae today. Our current simulations predict that Jupiter and Saturn will create a weak spiral structure in the wind of the Sun once it is an AGB star.”

    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 4:10 pm on September 7, 2020 Permalink | Reply
    Tags: "Scientists 'Zoom In' On Dark Matter Revealing The Invisible Skeleton Of The Universe", , , , , , Harvard Smithsonian Center for Astrophysics,   

    From Harvard-Smithsonian Center for Astrophysics: “Scientists ‘Zoom In’ On Dark Matter Revealing The Invisible Skeleton Of The Universe” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    9.2.20

    Center for Astrophysics | Harvard & Smithsonian
    Fred Lawrence Whipple Observatory
    Amy Oliver, Public Affairs
    amy.oliver@cfa.harvard.edu
    520-879-4406

    1
    Using the power of supercomputers, an international team of researchers has zoomed in on the smallest clumps of dark matter in a virtual universe. Published today in Nature, the study reveals dark matter haloes as active regions of the sky, teeming with not only galaxies, but also radiation-emitting collisions that could make it possible to find these haloes in the real sky.

    Dark matter—which makes up roughly 83% of the matter in the universe—is an important player in cosmic evolution, including in the formation of galaxies, which grew as gas cooled and condensed at the center of enormous clumps of dark matter. Over time, haloes formed as some dark matter clumps pulled away from the expansion of the universe due to their own enormous gravity. The largest dark matter haloes contain huge galaxy clusters—collections of hundreds of galaxies—and while their properties can be inferred by studying those galaxies within them, the smallest dark matter haloes, which typically lack even a single star, have remained a mystery until now.

    “Amongst the things we’ve learned from our simulations is that gravity leads to dark matter particles ‘clumping’ in overly dense regions of the universe, settling into what’s known as dark matter haloes. These can essentially be thought of as big wells of gravity filled with dark matter particles,” said Sownak Bose, a postdoc at the Center for Astrophysics | Harvard & Smithsonian, and one of the lead authors on the research. “We think that every galaxy in the cosmos is surrounded by an extended distribution of dark matter, which outweighs the luminous material of the galaxy by between a factor of 10-100, depending on the type of galaxy. Because this dark matter surrounds every galaxy in all directions, we refer to it as a ‘halo.’”

    Using a simulated universe, researchers were able to zoom in with the precision required to recognize a flea on the surface of the full Moon—with magnification up to 10 to the power of seven, or 10 followed by seven zeroes—and create highly detailed images of hundreds of virtual dark matter haloes, from the largest known to the smallest expected.

    “Simulations are helpful because they help us quantify not just the overall distribution of dark matter in the universe, but also the detailed internal structure of these dark matter haloes,” said Bose. “Establishing the abundance and the internal structure of the entire range of dark matter haloes that can be formed in the cold dark matter model is of interest because this enables us to calculate how easy it may be to detect dark matter in the real universe.”

    While studying the structure of the haloes, researchers were met with a surprise: all dark matter haloes, whether large or small, have very similar internal structures which are dense at the center and become increasingly diffuse moving outward. Without a scale-bar, it is almost impossible to tell the difference between the dark matter halo of a massive galaxy—up to 10^15 solar masses—and that of a halo with less than a solar mass—down to 10^-6 solar masses. “Several previous studies suggested that the density profiles for super-mini haloes would be quite different from their massive counterparts,” said Jie Wang, astronomer at the National Astronomical Observatories (NAOC) in Beijing, and a lead author on the research. “Our simulations show that they look similar across a huge mass range of dark haloes and that is really surprising.” Bose added that even in the smallest haloes which do not surround galaxies, “Our simulations enabled us to visualize the so-called ‘cosmic web.’ Where filaments of dark matter intersect, one sees the tiny, near spherical blobs of dark matter, which are the haloes themselves, and they are so universal in structure that I could show you a picture of a galaxy cluster with a million billion times the mass of the Sun, and an Earth-mass halo at a million times smaller than the Sun, and you would not be able to tell which is which.”

    Although the images of dark matter haloes from this study are the result of simulations, the simulations themselves are informed by real observational data. For astronomers, that means the study could be replicated against the real night sky given the right technology. “The initial conditions that went into our simulation are based on actual observational data from the cosmic microwave background radiation measurements of the Planck satellite, which tells us what the composition of the Universe is and how much dark matter to put in,” said Bose.

    During the study researchers tested a feature of dark matter haloes that may make them easier to find in the real night sky: particle collisions. Current theory suggests that dark matter particles that collide near the center of haloes may explode in a violent burst of high-energy gamma radiation, potentially making the dark matter haloes detectable by gamma-ray and other telescopes.

    “Exactly how the radiation would be detected depends on the precise properties of the dark matter particle. In the case of weakly interacting massive particles (WIMPs), which are amongst the leading candidates in the standard cold dark matter picture, gamma radiation is typically produced in the GeV range. There have been claims of a galactic center excess of GeV-scale gamma radiation in Fermi data, which could be due to dark matter or perhaps due to pulsars,” said Bose. “Ground-based telescopes like the Very Energetic Radiation Imaging Telescope Array System (VERITAS) can be used for this purpose, too.

    Veritas Four Čerenkov telescopes at the Fred Lawrence Whipple Observatory,Mount Hopkins, Arizona, US Altitude 2,606 m 8,550 ft.

    And, pointing telescopes at galaxies other than our own could also help, as this radiation should be produced in all dark matter haloes.” Wang added, “With the knowledge from our simulation, we can evaluate many different tools to detect haloes—gamma-ray, gravitational lensing, dynamics. These methods are all promising in the work to shed light on the nature of dark matter particles.”

    The results of the study provide a pathway both for current and future researchers to better understand what’s out there, whether we can see it or not. “Understanding the nature of dark matter is one of the Holy Grails of cosmology. While we know that it dominates the gravity of the universe, we know very little about its fundamental properties: how heavy an individual particle is, what sorts of interactions, if any, it has with ordinary matter, etcetera,” said Bose. “Through computer simulations we have come to learn about its fundamental role in the formation of the structure in our universe. In particular, we have come to realize that without dark matter, our universe would look nothing like the way it does now. There would be no galaxies, no stars, no planets, and therefore, no life. This is because dark matter acts as the invisible skeletal structure that holds up the visible universe around us.”

    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 3:05 pm on August 18, 2020 Permalink | Reply
    Tags: "The Sun May Have Started Its Life with a Binary Companion", , , , , Harvard Smithsonian Center for Astrophysics,   

    From Harvard-Smithsonian Center for Astrophysics: “The Sun May Have Started Its Life with a Binary Companion” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    August 18, 2020

    Amy Oliver
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    Fred Lawrence Whipple Observatory
    520-879-4406
    amy.oliver@cfa.harvard.edu

    1
    Artist’s conception of a potential solar companion, which theorists believe was developed in the Sun’s birth cluster and later lost. If proven, the solar companion theory would provide additional credence to theories that the Oort cloud formed as we see it today, and that Planet Nine was captured rather than formed in place.Credit: M. Weiss

    A new theory published today in The Astrophysical Journal Letters by scientists from Harvard University suggests that the Sun may once have had a binary companion of similar mass. If confirmed, the presence of an early stellar companion increases the likelihood that the Oort cloud was formed as observed and that Planet Nine was captured rather than formed within the solar system.

    Dr. Avi Loeb, Frank B. Baird Jr. Professor of Science at Harvard, and Amir Siraj, a Harvard undergraduate student, have postulated that the existence of a long-lost stellar binary companion in the Sun’s birth cluster—the collection of stars that formed together with the Sun from the same dense cloud of molecular gas—could explain the formation of the Oort cloud as we observe it today.

    Oort Cloud, The layout of the solar system, including the Oort Cloud, on a logarithmic scale. Credit: NASA, Universe Today

    Popular theory associates the formation of the Oort cloud with debris left over from the formation of the solar system and its neighbors, where objects were scattered by the planets to great distances and some were exchanged amongst stars. But a binary model could be the missing piece in the puzzle, and according to Siraj, shouldn’t come as a surprise to scientists. “Previous models have had difficulty producing the expected ratio between scattered disk objects and outer Oort cloud objects. The binary capture model offers significant improvement and refinement, which is seemingly obvious in retrospect: most Sun-like stars are born with binary companions.”

    If the Oort cloud was indeed captured with the help of an early stellar companion, the implications for our understanding of the solar system’s formation would be significant. “Binary systems are far more efficient at capturing objects than are single stars,” said Loeb. “If the Oort cloud formed as observed, it would imply that the Sun did in fact have a companion of similar mass that was lost before the Sun left its birth cluster.”

    More than just redefining the formation of our solar system, evidence of a captured Oort cloud could answer questions about the origins of life on Earth. “Objects in the outer Oort Cloud may have played important roles in Earth’s history, such as possibly delivering water to Earth and causing the extinction of the dinosaurs,” said Siraj. “Understanding their origins is important.”

    The model also has implications for the hypothesized Planet Nine, which Loeb and Siraj believe isn’t alone out there. “The puzzle is not only regarding the Oort clouds, but also extreme trans-Neptunian objects, like the potential Planet Nine,” said Loeb. “It is unclear where they came from, and our new model predicts that there should be more objects with a similar orbital orientation to Planet Nine.”

    Both the Oort cloud and the proposed location of Planet Nine are so distant from the Sun that direct observation and assessment are challenging for today’s researchers. But the Vera C. Rubin Observatory, which sees first light in early 2021, will confirm or deny the existence of Planet Nine and its origins. Siraj is optimistic, “If the VRO verifies the existence of Planet Nine, and a captured origin, and also finds a population of similarly captured dwarf planets, then the binary model will be favored over the lone stellar history that has been long-assumed.”

    If the Sun did have an early companion that contributed to the formation of the outer solar system, its current absence begs the question: where did it go? “Passing stars in the birth cluster would have removed the companion from the Sun through their gravitational influence,” said Loeb. “Before the loss of the binary, however, the solar system already would have captured its outer envelope of objects, namely the Oort cloud and the Planet Nine population.” Siraj added, “The Sun’s long-lost companion could now be anywhere in the Milky Way.”

    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 10:31 pm on July 23, 2020 Permalink | Reply
    Tags: "Gamma-ray Scientists "Dust Off" Intensity Interferometry and Upgrade Technology with Digital Electronics Using Larger Telescopes and Improved Sensitivity", , , , , Harvard Smithsonian Center for Astrophysics, Stellar Intensity Interferometry, , VERITAS is at the Fred Lawrence Whipple Observatory in Amado Arizona USA Altitude Altitude 2606 m 8550 ft., VERITAS- the world's most sensitive very-high-energy gamma-ray observatory detects gamma rays via the extremely brief flashes of blue Čerenkov light they create when absorbed in Earth's atmosphere., Čerenkov telescopes catch blue light flashes indicating gamma radiation.   

    From Harvard-Smithsonian Center for Astrophysics: “Gamma-ray Scientists “Dust Off” Intensity Interferometry, Upgrade Technology with Digital Electronics, Larger Telescopes, and Improved Sensitivity” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    July 20, 2020
    Amy Oliver
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    Fred Lawrence Whipple Observatory
    520-879-4406
    amy.oliver@cfa.harvard.edu

    1
    Artist’s conception illustrating improved angular resolution, as was achieved using a scalable version of the intensity interferometry technique developed at VERITAS. Credit: M. Weiss

    Scientists in the VERITAS Collaboration have measured the angular diameter of stars using Stellar Intensity Interferometry for the first time in nearly 50 years, and demonstrated both improvements to the sensitivity of the technique and its scalability using digital electronics.

    Led by astronomers from the Center for Astrophysics | Harvard & Smithsonian and the University of Utah, VERITAS (Very Energetic Radiation Imaging Telescope Array System) scientists measured the angular diameters of Beta Canis Majoris—a blue giant star located 500 light-years from the sun—and Epsilon Orionis—a blue supergiant star located 2,000 light-years from the sun.

    “A proper understanding of stellar physics is important for a massive range of astronomical fields, from exoplanet studies to cosmology, and yet they are often seen as point sources of light due to their great distances from Earth,” said Nolan Matthews, University of Utah. “Interferometry has been widely successful in achieving the angular resolution needed to spatially resolve stars and we’ve demonstrated the capability to perform optical intensity interferometry measurements with an array of many telescopes that in turn will help to improve our understanding of stellar systems.” Michael Daniel, Operations Manager, VERITAS, added, “Resolving something the size of a coin on the moon is a marvelous thing. Knowing if that coin is a dime or a nickel is something even more special still. If you want that level of detail, then you want intensity interferometry to work on this scale.”

    VERITAS used all four of its gamma-ray telescopes, located at the Fred Lawrence Whipple Observatory in Amado, Arizona,USA to increase its coverage and provide greater resolution for observation.

    “This is the first demonstration of the original Hanbury Brown and Twiss technique using an array of optical telescopes,” said David Kieda, astronomer, University of Utah, and Principal Investigator. “Modern electronics allow us to computationally combine light signals from each telescope. The resulting instrument has the optical resolution of a football-field-sized reflector.”

    Typically observing dark, moonless skies for Čerenkov light—blue flashes indicative of the presence of gamma-rays—VERITAS scientists made use of the nights surrounding the full moon to conduct the study. “The moon doesn’t disrupt observations for intensity interferometry,” said Daniel. “This opens up new scientific horizons for the VERITAS telescopes and similar facilities.”

    The first telescopes to perform stellar measurements using intensity interferometry were the Narrabri telescopes in the 1970s. “Narrabri measured 32 stars in the southern hemisphere, and to significantly improve upon that result required a large leap in technology,” said Wystan Benbow, Director, VERITAS. “Right now we are pathfinding for the future Čerenkov Telescope Array (CTA); we have proven that we can add 100 telescopes to this design, enabling astronomers to image features on stellar surfaces with unparalleled optical resolution.”

    MAGIC Čerenkov telescope array at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    A novel gamma ray telescope under construction on Mount Hopkins Arizona USA at the Fred Lawrence Whipple Observatory Altitude 2606 m (8550 ft). A large project known as the Čerenkov Telescope Array composed of hundreds of similar telescopes to be situated in the Canary Islands [at the Roque de los Muchachos Observatory on the island of La Palma, Spain, sited on a volcanic peak 2267 metres (7438 ft)] and Chile [at ESO’s Cerro Paranal site]. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

    The future for intensity interferometry is bright, and VERITAS scientists have a few ideas about where it could go, from creating a larger catalog of stars, to measuring space objects and phenomena, like the properties of interacting binary star systems, rapidly rotating stars, and potentially the pulsation of Cepheid variables, among others.

    Having previously measured the apparent diameter of some very small stars in the sky using the asteroid occultation method, the study is one more indicator that gamma-ray telescopes, and their scientists, are more than meets the eye.

    “New technology is a science multiplier,” said Peter Kurczynski, Program Director for Advanced Technologies and Instrumentation at the National Science Foundation, which contributed funding for the project. “It enables discoveries that would be otherwise impossible.” Benbow added, “There’s great potential for intensity interferometry to make leaps forward now that we know it can work on gamma-ray telescopes. We’re excited to see, and create, what comes next.”

    The VERITAS SII project was supported with AST and PHYS grants from the National Science Foundation, and by the University of Utah. The results of the study are published in Nature Astronomy.

    About VERITAS

    VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a ground-based array of four, 12-m optical reflectors for gamma-ray astronomy located at the Center for Astrophysics | Harvard & Smithsonian, Fred Lawrence Whipple Observatory in Amado, Arizona.

    Veritas Four Čerenkov telescopes at the Fred Lawrence Whipple Observatory,Mount Hopkins, Arizona, US Altitude 2,606 m 8,550 ft

    VERITAS is the world’s most sensitive very-high-energy gamma-ray observatory, and it detects gamma rays via the extremely brief flashes of blue Čerenkov light they create when they are absorbed in Earth’s atmosphere.

    VERITAS is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, and the Smithsonian Institution, NSERC in Canada, and the Helmholtz Association in Germany.

    The VERITAS Collaboration consists of about 80 scientists from 20 institutions in the United States, Canada, Germany and Ireland.

    For more information about VERITAS visit http://veritas.sao.arizona.edu

    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 9:25 am on June 26, 2020 Permalink | Reply
    Tags: "Inferring The Temperature Structure of Circumstellar Disks from Polarized Emission", , , , , Harvard Smithsonian Center for Astrophysics   

    From Harvard-Smithsonian Center for Astrophysics: “Inferring The Temperature Structure of Circumstellar Disks from Polarized Emission” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    1
    An ALMA submillimeter image of the dusty circumstellar disc around a young star. Astronomers are using ALMA polarization maps of the radiation from discs simialr to this one to infer the presence of a temperature gradient, and infer possible accretion onto the disc. (The asterisk marks the possible location of the embedded star; a scale of ten astronomical units is indicated.)Lee, Chin-Fei et al., 201?

    Polarized light is a familiar phenomenon because the scattering or reflection of light results in one of its two components being preferentially absorbed. The majority of sunlight on Earth, for example, is preferentially polarized due to scattering in the atmosphere (this helps make polarized sunglasses effective). Electromagnetic radiation from astrophysical sources can also be polarized, typically because of scattering from elongated dust grains that are aligned with each other by the local magnetic fields. These fields are thought to play a major, perhaps even a dominant role in controlling the shapes and motions of interstellar gas clouds and are extremely difficult to measure directly. Observations of polarization by dust grains offer a unique way to probe the magnetic fields.

    The polarized emission from aligned grains in discs around young stellar objects is of particular interest to astronomers studying how planets develop and evolve in these discs. The polarized emission can reveal not only the details of the magnetic fields present but also (depending on the grain shapes and properties) other structural features of the disk environment, for example teh presence of anisotropic stellar radiation.

    The ALMA submillimeter facility has recently had success detecting polarized emission from a number of young circumstellar discs. CfA astronomer Ian Stephens was a member of a team that used ALMA to observe the strength of such emission at multiple wavelengths. They conclude that magnetic field processes are unlikely to be the only mechanism at work, and they demonstrate that a temperature gradient across the disc can modify the polarized emission from aligned dust grains to more closely replicate observed data than the simple magnetic field models. The scientists’ analysis of polarized dust emission in disks finds that the effects of a temperature gradient on polarization are strongest when a disc is viewed edge-on, and they validate their conclusion with detailed models. Because temperature gradients can be influenced by accretion onto the disk, these polarization results also provide a new method of probing disc accretion. Accretion heating, for example, can change the angle of the polarization with respect to the disc.

    Science paper:
    “Probing the Temperature Structure of Optically thick Discs using Polarized Emission of Aligned Grains,”
    MNRAS

    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 1:59 pm on June 19, 2020 Permalink | Reply
    Tags: "The Megamaser Cosmology Project Measures the Age of the Universe", , , , , Harvard Smithsonian Center for Astrophysics   

    From Harvard-Smithsonian Center for Astrophysics: “The Megamaser Cosmology Project Measures the Age of the Universe” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    1
    The Hubble Ultra Deep Field of galaxies; the smallest and reddest of the galaxies seen here date from when the universe was only about 800 million years old. The value of a key parameter of big bang cosmology, the constant that provides the age of the universe, has been in dispute recently because different measurement methods give significantly different results. Astronomers have now used a new method, megamaser emission from six distant galaxies, to arrive a third and arguably more accurate value. Credit: NASA, ESA, and S. Beckwith (STScI) and the HUDF Team

    A maser, like a laser, is a source of bright, monochromatic electromagnetic radiation, with the difference being that maser radiation is not optical light but rather longer wavelength microwave radiation. Dense molecular clouds in interstellar space sometimes produce natural masers when specific molecules (water and OH are two examples) or atoms are stimulated by the local conditions to emit very narrow-line radiation.

    Such astronomical masers were first identified in space over fifty years ago, and have since been found in many locations in our Milky Way as well as in other galaxies, with the most spectacular examples found in regions of active star formation. In some cases the energy emitted in a single maser line exceeds the emission from the Sun over its entire visible spectrum making masers valuable diagnostic probes of their local conditions. These “megamasers” can be found in the nuclear regions of galaxies with active supermassive black holes and their brightness makes them potentially useful tools for cosmological studies.

    Ninety years after Edwin Hubble discovered the systematic motions of galaxies and George Lemaitre explained them as cosmic recession using Einstein’s relativity equations, observational cosmology today is facing a challenge. No precise and consistent value of the expansion, as quantified by the Hubble Constant (“Ho”), has been found. Values deduced from the properties of galaxies or from the cosmic microwave background radiation (CMBR) are each precise — but they disagree with each other at roughly the ten percent level and observational errors, although possible, seem too small to account for the differences. Many astronomers suspect the difference is real, reflecting something currently missing from our picture of the cosmic expansion process, perhaps connected with the fact that the CMBR data arise from a vastly different epoch of cosmic time than do the galaxy data and reflecting something still not known about the processes that power the big bang.

    The Megamaser Cosmology Project is a multi-year campaign to find, monitor, and map systems with the goal of constraining Ho to a precision of several percent with precise geometric distance measurements to water megamaser galaxies whose known recession velocities were also remeasured precisely. CfA astronomers Dom Pesce and Mark Reid are lead members of the team, which has just published its improved value for Ho of 73.9 +-3.0 (in usual units) corresponding to an age of the universe (with some assumptions) of 12.9 +-0.5 billion years. The team used their analyses of megamasers in six galaxies for this result. For comparison, other projects using measurements from galaxies have reported a consistent value, about 74.0, however the CMBR results from the Planck satellite give a value of value for Ho of about 67.4 and a corresponding age that is significantly older: 14.2 billion years. The team notes that their future megamaser observations will improve on this precision and help astronomers address this critical discrepancy.

    Science paper:
    “The Megamaser Cosmology Project. XIII. Combined Hubble Constant Constraints,”
    The Astrophysical Journal Letters

    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 8:40 am on May 3, 2019 Permalink | Reply
    Tags: , , , , Harvard Smithsonian Center for Astrophysics, Smithsonian Launches 'Journey through an Exploded Star" 3D Interactive Experience'   

    From Harvard-Smithsonian Center for Astrophysics: “Smithsonian Launches ‘Journey through an Exploded Star” 3D Interactive Experience'” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    April 30, 2019

    Contacts:

    Darren Milligan
    Smithsonian Center for Learning and Digital Access, Washington, DC
    (202) 633-5291
    milligand@si.edu

    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.
    (617) 496-7998
    mwatzke@cfa.harvard.edu

    Tyler Jump
    Center for Astrophysics | Harvard & Smithsonian
    (917) 816-4001
    tyler.jump@cfa.harvard.edu

    1

    The Smithsonian today made available a new online interactive that allows users to explore a three-dimensional (3D) visualization of the remnants of a supernova, or exploded star.

    Designed for use by both general audiences and high school science classrooms, the free materials, available at s.si.edu/supernova, include an interactive simulation, a 360° video, and a multimedia instructional package.

    2

    The project was created by the Smithsonian Center for Learning and Digital Access in conjunction with the Center for Astrophysics | Harvard & Smithsonian (CfA), a collaboration that includes the Smithsonian Astrophysical Observatory.

    To create the visualizations, the project uses data from the Chandra X-ray Observatory and Spitzer Space Telescope, the National Optical Astronomy Observatory’s Mayall Telescope, and the MIT/Michigan/Dartmouth Observatory’s Hiltner Telescope.

    NASA/Chandra X-ray Telescope

    NASA/Spitzer Infrared Telescope


    NOAO/Mayall 4 m telescope at Kitt Peak, Arizona, USA, Altitude 2,120 m (6,960 ft)

    3
    MIT/Michigan/Dartmouth Observatory’s Hiltner Telescope

    “Journey” features the data visualization work of Kimberly Arcand, visualization and emerging technology lead for Chandra, which is operated and controlled on behalf of NASA by the CfA.

    “All of that data has to be translated and processed in a way that humans can see, so it’s really important to be able to study our Universe using different kinds of light,” said Arcand. “Each band of light gives you different information, so it’s like adding puzzle pieces to fit into the greater whole.”

    “Journey through an Exploded Star” offers three ways to explore content:

    — An online interactive simulation in which users navigate the fiery remains of a supernova and manipulate the real data to make their own visualization of the cosmos. (Closed Captioned, works across desktop browsers, and requires no software downloads.)

    — A 360° video tour, narrated by Arcand, explains how and why scientists study supernovas such as Cassiopeia A: to gain a comprehensive picture of the cosmos. (Works on desktop, mobile, and Google Cardboard devices.)

    — A high school classroom multimedia instructional package begins with the fundamentals of the electromagnetic spectrum and illustrates the production of elements from the explosions of stars. (Aligned to Next Generation Science Standards (HS-ESS1-3 and HS-PS4).)

    The director of the Smithsonian Center for Learning and Digital Access, Stephanie L. Norby, said, “Projects such as this one make science learning both exciting and relevant for students. Using media tools, they can make a personal connection to topics that may initially seem esoteric to discover that there are forces that connect everyone to the stars.”

    The Smithsonian Center for Learning and Digital Access makes all of this content freely available in its Smithsonian Learning Lab.

    4

    About the Smithsonian Center for Learning and Digital Access

    The Smithsonian established the Smithsonian Center for Learning and Digital Access in 1976 to serve public education by bringing Smithsonian collections and expertise into the nation’s classrooms. For more than 40 years, it has published educational materials and provided one access point to Smithsonian educational resources. To understand the needs of teachers, students, and museum educators, the Center spent more than a decade in active experimentation and research, culminating in the launch of a new online platform—the Smithsonian Learning Lab. Since its launch in 2016, museum and classroom educators have used the Lab’s tools to create thousands of new examples—ranging from experiments to models—for using Smithsonian resources for learning. The Center now studies how teachers and students use digital museum resources and broadly disseminates this knowledge through professional development to advance museum and digital learning.

    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.

     
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