Carnegie Science News - Astronomy/Cosmology

Carnegie Institution for Science

Mirror Casting Event for the Giant Magellan Telescope

Washington, D.C.—On January 14, 2012, the second 8.4-meter (27.6 ft) diameter mirror for the Giant Magellan Telescope (GMT) will be cast inside a rotating furnace at the University of Arizona’s Steward Observatory Mirror Lab (SOML) underneath the campus football stadium. The Mirror Lab will host a special event to highlight the milestone of creating the optics for the Giant Magellan Telescope. The Carnegie Institution is a founding member of the GMTO partnership.*

Members of the media are invited to visit the Mirror Lab on Saturday morning, January 14, 2012, between 9:00 and 11:00 a.m. MST, to see the liquid glass as it is spun cast in a rotating oven at a temperature of 1170 degrees C (2140° F). This casting marks another major step in the construction of the Giant Magellan Telescope. There will be opportunities to interview leading scientists and engineers involved in the project.

This event is supported by the University of Arizona’s Steward Observatory and College of Science and by the GMTO Corporation (GMTC), a nonprofit entity with project offices based in Pasadena, California.*
The GMT features an innovative design using seven mirrors, each 8.4 meters in diameter, arranged in a floral pattern to form a single mirror 24.5 meters (80 feet) in diameter. It will bring starlight to a common focus via a set of adaptive secondary mirrors configured in a similar seven-fold pattern.

“In this design the outer six mirrors are off-axis paraboloids and represent the greatest optics challenge ever undertaken in astronomical optics by a large factor” said Roger Angel, Director of the Steward Observatory Mirror Lab.

The GMT will allow astronomers to answer some of the most pressing questions about the cosmos including the detection, imaging, and characterization of planets orbiting other stars, the nature of dark matter and dark energy, the physics of black holes, and how stars and galaxies evolved during the earliest phases of the universe.

Patrick McCarthy, GMT project director and staff astronomer with the Carnegie Observatories, remarked, “This second GMT casting is going forward now because the primary optics are on the critical path for the project and because the polishing of the first off-axis 8.4-meter GMT mirror is very close to completion, with an optical surface accuracy within about 25 nanometers, or about one-thousandth the thickness of a human hair.”

Like other mirrors produced by the Mirror Lab, the GMT mirrors are designed to be spun cast, thereby achieving the basic front surface in the shape of a paraboloid. A paraboloid is the shape taken on by water in a bucket when the bucket is spun around its axis; the water rises up the walls of the bucket while a depression forms in the center. Precision grinding and polishing of the surface is then undertaken to create the figure of an off-axis parabloid.

“The novel technology developed at the Mirror Lab is creating a whole new generation of large telescopes with unsurpassed image sharpness and light collecting power,” said Wendy Freedman, Director of the Carnegie Observatories and Chair of the GMTO Board. “Themirrors in the twin Magellan Telescopes at our Las Campanas Observatory site are performing superbly and led to our adoption of this technology for the GMT.”

Some 21 tons of borosilicate glass, made by the Ohara Corporation, flow into a pre-assembled mold to create a lightweight honeycomb glass structure that is very stiff and quickly adjusts to changes in nighttime air temperature, each resulting in sharper images. The Mirror Lab has already produced the world's four largest astronomical mirrors, each 8.4 meters in diameter. Two are in operation in the Large Binocular Telescope (LBT)—currently the largest telescope in the world, one is for the Large Synoptic Survey Telescope (LSST), and the fourth is the first off-axis mirror for GMT. The Mirror Lab has also produced five 6.5-meter mirrors, two of which are in the twin Magellan telescopes at Las Campanas Observatory in Chile.

“Astronomical discovery has always been paced by the power of available telescopes and imaging technology. The GMT allows another major step forward in both sensitivity and image sharpness” said Peter Strittmatter, Director of Steward Observatory. “In fact the GMT will be able to acquire images 10 times sharper than the Hubble Space Telescope and will provide a powerful complement not only to NASA’s 6.5-meter James Webb Space Telescope (JWST) but also to the Atacama Large Millimeter Array (ALMA) and the Large Synoptic Survey Telescope (LSST), both located in the southern hemisphere.”

The GMT is set to begin science operations in 2020 at Carnegie’s Las Campanas Observatory, exploiting the clear dark skies of the Atacama Desert in northern Chile.
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*The GMTO manages the GMT Project on behalf of its...

Solving a supernova mystery

Pasadena, CA— A team of scientists, including Carnegie’s Mansi M. Kasliwal, has observed the early stages of a Type Ia supernova that is only 21 million light years away from Earth--the closest of its kind discovered in 25 years. The Palomar Transient Factory team’s detection of a supernova less than half a day after it exploded will refine and challenge our understanding of these stellar phenomena. Their breakthrough observations are published December 15 in Nature.

Type Ia supernovae are violent stellar explosions. Observations of their brightness are used to determine distances in the universe and have shown scientists that the universe is expanding at an accelerating rate. The Nobel Prize in Physics was awarded December 10 to three astronomers for their "discovery of the accelerating expansion of the Universe through observations of distant supernovae.”

The PTF team, led by Professor Shri Kulkarni of the California Institute of Technology, discovered this supernova, named SN2011fe, just 11 hours after it exploded. They were able to pinpoint the explosion in the Pinwheel Galaxy to August 23 at about 4:30 p.m. Universal Time.

“For several years, I had been taking images with robotic telescopes at Palomar Observatory of the Pinwheel Galaxy every night I possibly could, hoping it would give birth to a rare cosmic feat,” Kasliwal said. “When we saw SN2011fe, I fell off my chair as its brightness was too faint to be a supernova and too bright to be nova. Only follow-up observations in the next few hours revealed that this was actually an exceptionally young Type Ia supernova."

The widely accepted theory is that Type Ia supernovae are thermonuclear explosions of a white dwarf star that’s part of a binary system--two stars that are physically close and orbit around a common center of mass.

There are two different models for how Type Ia supernovae are created from this type of binary system. In the so-called double-degenerate (or DD) model, the orbit between two white dwarf stars shrinks until the lighter star’s path is disrupted and it moves close enough for some of its matter to be absorbed into the primary white dwarf and initiate an explosion. In the so-called single-degenerate (or SD) model, the white dwarf slowly accretes mass from a different, non-white dwarf type of star, until it reaches an ignition point. There are three potential methods for the transfer of mass and--depending on which one is used--the second star is likely to be a red giant, a helium star, or a so-called subgiant or main-sequence star.

Observations of the early stages of the supernova--presented in a paper by lead author Peter Nugent of Lawrence Berkeley Laboratory--showed direct evidence that the primary star was a type of white dwarf called a carbon-oxygen white dwarf.
Very sensitive and early radio and X-ray observations, presented in a separate paper to be published in The Astrophysical Journal, show no evidence of interaction with surrounding material. Combining this data with an analysis of historical images, the team ruled out luminous red giants and the vast majority of helium stars for the second star in the binary system before the explosion.

These clues meant that the secondary star was either another white dwarf, as in the DD model, or a subgiant or main-sequence star, as created by one of the three SD model methods.

Analysis of the matter ejected by the supernova’s explosion suggests that the second star is less likely to be another white dwarf. Thus, the solution to the mystery of SN2011fe’s origin is probably a primary white dwarf accreting matter from a neighboring subgiant or main-sequence star.

"The fact that we discovered this supernova in its infancy, and that the Pinwheel Galaxy is in our cosmic backyard, has given us an unprecedented opportunity to make this the best studied supernova to date,” Kulkarni said.

 

Caption: SN 2011fe in the Pinwheel Galaxy (M101) at maximum brightness, a composite of optical data from the Las Cumbres Observatory Global Telescope Network 0.8m Byrne Observatory Telescope at the Sedgwick Reserve and (purple) hydrogen emission data from the Palomar Transient Factory. The left side shows the galaxy with no labels and the right shows the same with the SN2011fe labled.

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The Palomar Transient Factory (PTF) is based on the 48-inch Oschin Schmidt telescope and the 60-inch telescope of the Palomar Observatory of the California Institute of Technology and is a collaboration of the following institutions: California Institute of Technology, Columbia University, Las Cumbres Observatory Global Telescope, Lawrence Berkeley Laboratory, Oxford University, the University of California at Berkeley and the Weizmann Institute of Science. The Principal Investigator of PTF is Professor S. R. Kulkarni.

This work received...

Spend an L.A. Evening with the Giant Magellan Telescope

Pasadena, CA-Join a discussion with leading astronomers about how one of the world’s largest telescopes, the Giant Magellan Telescope, will help solve some of the most vexing problems in astronomy today—from the nature of dark energy and dark matter to finding signatures of life on other planets. The event will take place November 20, 2011, at the Hyatt Regency Century Plaza, 2025 Avenue of the Stars, Los Angeles, CA, from 1 to 5 PM. Tickets are $15 and include light refreshments. Journalists who register are admitted free.

The Giant Magellan Telescope (GMT) is a product of more than 100 years of astronomical research and telescope building. It will be located at one of the world’s premier astronomical observing sites, the Las Campanas Observatory in the Chilean Andes. As one of the most powerful astronomical observatories, it will have more light gathering power than all of the current telescopes in Chile combined. The GMT will use the latest techniques in what is known as adaptive optics to remove blurring caused by the Earth’s atmosphere to produce visible and infrared images that are up to ten times sharper than those from the Hubble Space Telescope. The unprecedented clarity and sensitivity of these images will provide astronomers with a powerful new tool to study still-unsolved mysteries of the universe, including the formation of planetary systems, the growth of black holes, even the evolutions of the universe.

The speakers are chairperson of the Giant Magellan Telescope Organization board and director of the Carnegie Observatories, Wendy Freedman; Charles Alcock of Harvard University; Jacob Bean and Michael Gladders of the University of Chicago; and Juna Kollmeier and Josh Simon of Carnegie.

The GMT features an innovative design of seven 8.4 meter, or 27 foot, diameter primary mirrors arranged in a floral-like hexagon. The seven mirrors, six of which are off-axis, will work in concert to produce a single telescope 25 meters or 82 feet in diameter. The mirrors are being developed at the Steward Observatory Mirror Laboratory (SOML) at the University of Arizona.

The Giant Magellan Telescope Organization (GMTO) in Pasadena, CA manages the project on behalf of its international partners: Astronomy Australia Ltd., the Australian National University, the Carnegie Institution for Science, Harvard University, the Korea Astronomy and Space Science Institute, the Smithsonian Institution, Texas A&M University, the University of Arizona, The University of Texas at Austin, and, the University of Chicago. For more information, visit www.gmto.org.
 

New discovery sheds light on the ecosystem of young galaxies

Pasadena, CA— A team of scientists, led by Michael Rauch from the Carnegie Observatories, has discovered a distant galaxy that may help elucidate two fundamental questions of galaxy formation: How galaxies take in matter and how they give off energetic radiation. Their work will be published in the Monthly Notices of the Royal Astronomical Society.

During the epoch when the first galaxies formed, it is believed that they radiated energy, which hit surrounding neutral hydrogen atoms and excited them to the point where they were stripped of electrons. This produced the ionized plasma that today fills the universe. But little is known about how this high-energy light was able to escape from the immediate surroundings of a galaxy, known as the galactic halo. The galaxies we observe today tend to be completely surrounded by gaseous halos of neutral hydrogen, which absorb all light capable of ionizing hydrogen before it has a chance to escape.

Rauch and his team, using the Magellan Telescopes at Las Campanas Observatory and archival images from the Hubble Space Telescope, discovered a galaxy with an extended patch of light surrounding it. The objects appearance means that roughly half of the galaxy’s radiation must be escaping and exciting hydrogen atoms outside of its halo.

The key to the escape of radiation can be found in the unusual, distorted shape of the newly observed galaxy. It appears that the object had recently been hit by another galaxy, creating a hole in its halo, allowing radiation to pass through.

“The loss of radiation during galactic interactions and collisions like the one seen here may be able to account for the re-ionization of the universe”, Rauch said. “This galaxy is a leftover from a population of once-numerous dwarf galaxies. And looking back to a time when the universe was more dense, crashes between galaxies would have been much more common than today.”

The new observation also helps scientists better understand the flow of inbound matter, from which a galaxy originally forms. In the present case, the escaping ionizing radiation illuminated a long train of incoming gas, which is feeding new matter into the galaxy. The existence of such structures had been predicted by theory, but they had not been seen previously because they barely emit any light of their own.

The co-authors on this paper are George Becker and Martin Haehnelt from the Kavli Institute for Cosmology at Cambridge University, Jean-Rene Gauthier from The Kavli Institute for Cosmological Physics at the University of Chicago, Swara Ravindranath from the Inter-University Centre for Astronomy and Astrophysics, and Wallace Sargent from the Palomar Observatory at California Institute of Technology.
 

Supernovae Parents Found

Pasadena, CA— Type Ia supernovae are violent stellar explosions whose brightness is used to determine distances in the universe. Observing these objects to billions of light years away has led to the discovery that the universe is expanding at an accelerating rate, the foundation for the notion of dark energy. Although all Type Ia supernovae appear to be very similar, astronomers do not know for certain how the explosions take place and whether they all share the same origin. Now, researchers have examined new and detailed observations of 41 of these objects and concluded that there are clear signatures of gas outflows from the supernova ancestors, which do not appear to be white dwarfs.The research is published in the August 12 issue of Science by a team of astronomers including Josh Simon, Mark Phillips, Nidia Morrell, and Ian Thompson from Carnegie Observatories, and led by Assaf Sternberg and Avishay Gal-Yam of the Weizmann Institute of Science in Israel.

The widely accepted theory is that Type Ia supernovae are thermonuclear explosions of a white dwarf star in a close binary system. There are two competing scenarios for supernova ancestry. In the so-called single-degenerate model, the accompanying star in the binary is a main-sequence star or evolved star. In the competing double-degenerate model, the companion is another white dwarf—a very dense star in its final evolutionary stage.

“Because we don’t know what the things blowing up actually are, we don’t quite understand why they should all be so similar,” explained coauthor Josh Simon of the Carnegie Observatories. “That raises the possibility that Type Ia supernovae that occurred 7 billion years ago—the ones that allow us to measure the repulsive force we call dark energy—might be different in some subtle way from the ones occurring now. Maybe they are a little bit brighter than the ancient ones, for example.”

Mark Phillips, also from Carnegie added, “We wanted to get a better understanding of what the stars look like before the explosion to help determine the origin of their brightness. That information will allow us to be sure that there are no errors of this type distorting the dark energy measurements.”

The astronomers looked for absorption by sodium atoms in the spectrum of each of the 41 supernovae. Sodium is a telltale sign of cool, neutral gas in the vicinity of the explosion. By measuring the speed of the sodium clouds using the Doppler shift, they determined that the majority of the supernovae show sodium gas moving away from the explosion site and toward the Earth.

“If the star system originally contained two white dwarfs before the supernova, then there shouldn’t be any sodium,” remarked Carnegie’s Nidia Morrell. “The fact that we detected the sodium shows that one of the stars must not have been a white dwarf.”

The astronomers ruled out other possible sources of the sodium absorption features including interstellar clouds or a galactic-scale wind blown by the host galaxy.

“The low velocities and narrowness of the features suggest that the absorption is from material very close to the supernova that was ejected by the parent system before the explosion. Typically, gas with these characteristics is attributed to the stellar wind blown by red giant companion stars, not white dwarfs,” concluded Simon.

The finding is an important first step toward understanding the details of how Type Ia supernovae explode and the origin of their immense luminosity.

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Authors on the paper are the following: A. Sternberg, and A. Gal-Yam Weizmann Institute of Science; Josh Simon, Mark Phillillps, Nidia Morrell and Ian Thompson of the Carnegie Observatories; D. leaonard, San Diego State University; R. Quimby, CalTech; I. Ivans University of Utah; J. Marshall Texas A & M; A. Filippenko, G. Marcy and J. Bloom UC Berkley; F. Patat, ESO; R. Foley, Harvard-Smithsonian Center for Astrophysics; D. Yong The Australian National University; B. Penprase, D. Beeler, Pomona College; C. Prieto, Universidad de La Laguna; G. Stringfellow University of Colorado.
 

Earliest watery black hole discovered

Pasadena, CA— Water really is everywhere. A team of astronomers have found the largest and farthest reservoir of water ever detected in the universe—discovered in the central regions of a distant quasar. Quasars contain massive black holes that are steadily consuming a surrounding disk of gas and dust; as it eats, the quasar spews out huge amounts of energy. The energy from this particular quasar was released some 12 billion years ago, only 1.6 billion years after the Big Bang and long before most of the stars in the disk of our Milky Way galaxy began forming.

The research team includes Carnegie’s Eric Murphy, as well as scientists from the Jet Propulsion Laboratory, the California Institute of Technology, University of Maryland, University of Colorado, University of Pennsylvania, and the Institute for Space and Astronautical Science in Japan. Their research will be published in Astrophysical Journal Letters.

The quasar’s newly discovered mass of water exists in gas, or vapor, form. It is estimated to be at least 100,000 times the mass of the Sun, equivalent to 34 billion times the mass of the Earth or 140 trillion times the mass of water in all of Earth’s oceans put together.

Since astronomers expected water vapor to be present even in the early universe, the discovery of water is not itself a surprise. There is water vapor in the Milky Way, although the amount is 4,000 times less massive than in the quasar. There is other water in the Milky Way, but it is frozen and not vaporous.

Nevertheless water vapor is an important trace gas that reveals the nature of the quasar. In this particular quasar, the water vapor is distributed around the black hole in a gaseous region spanning hundreds of light years in size (a light year is about six trillion miles). The gas is unusually warm and dense by astronomical standards. It is five-times hotter and 10- to 100-times denser than what is typical in galaxies like the Milky Way.

The large quantity of water vapor in the quasar indicates that it is bathing the gas in both X-rays and infrared radiation. The interaction between the radiation and water vapor reveals properties of how the gas is influenced by the quasar. For example, analyzing the water vapor shows how the radiation heats the rest of the gas. Furthermore, measurements of the water vapor and of other molecules, such as carbon monoxide, suggest that there is enough gas to enable the black hole to grow to about six times its size. Whether or not this has happened is unclear, the astronomers say, since some of the gas could condense into stars or being ejected from the quasar.

A major new telescope in the design phase called CCAT will allow astronomers to measure the abundance of water vapor in many of the early Universe’s galaxies.

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Funding for Z-Spec was provided by NSF, NASA, the Research Corporation, and the partner institutions. The Caltech Submillimiter Observatory is operated by the California Institute of Technology under a contract from the NSF. CARMA was built and is operated by a consortium of universities—The California Institute of Technology, University of California Berkeley, University of Maryland College Park, University of Illinois Urbana-Champaign, and the University of Chicago—with funding from a combination of state and private sources, as well as the NSF and its University Radio Observatory program.

 

Caption: Image of a distant quasar courtesy of NASA Goddard Space Flight Center.
 

George Mitchell Commits $25 Million to Giant Magellan Telescope

Pasadena, CA- George P. Mitchell, founder of Mitchell Energy & Development Corp. and The Cynthia and George Mitchell Foundation, has committed an unprecedented $25-million gift to the Giant Magellan Telescope (GMT) project. Half of the gift, $12.5 million, has been donated to the Carnegie Institution for Science and half to Texas A&M University, Mitchell’s alma mater. Carnegie and Texas A&M are two of the GMT’s 10 partners.* The gift will help support the GMT during the next five years.

“George Mitchell has been a driving force behind this project from the beginning,” commented Wendy Freedman, chair of the board of directors for the Giant Magellan Telescope Organization (GMTO) and director of the Carnegie Observatories. “His generosity, vision, and dedication to the project will help define the future of astronomy.”

The GMT features an innovative design of seven 8.4 meter, or 27-foot, diameter primary mirrors arranged in a hexagon. The seven mirrors, six of which are off-axis, will produce a single telescope 24.5 meters or 80 feet in diameter. The mirrors are under development at the Steward Observatory Mirror Laboratory (SOML) at the University of Arizona, another GMT partner. The first off-axis mirror is in the final stages of polishing and is expected to be completed by the end of the year.

The GMT will open a new window to the universe. It is set to begin science operations at Carnegie’s Las Campanas Observatory in the Atacama Desert in northern Chile in 2019. Its resolving power will be far larger than any other telescope ever built and will allow astronomers to answer the most pressing questions of the day including the nature of dark matter and dark energy, black holes, planets orbiting other stars in our galaxy, and the evolution stars and galaxies in the earliest phases of the universe.

“This is an extraordinary time for astronomy given the many mysteries, including dark energy and dark matter, that we do not understand,” remarked Carnegie president Richard Meserve. “George Mitchell’s exceptional generosity will help us to solve them.”

“This gift not only brings the dream of the Giant Magellan Telescope much closer to becoming reality, but also helps propel Texas A&M and the entire state of Texas to the forefront in the important fields of physics and astronomy,” said Texas A&M president R. Bowen Loftin.

Thus far, $255.5 million has been raised to support the GMT, a $700-million project. The GMT will have 10 times the resolution of the Hubble Space Telescope and will operate in the new era of the James Webb Space Telescope, Hubble’s successor.
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*The Giant Magellan Telescope Organization is a nonprofit corporation based in Pasadena, California. The GMTO manages the GMT Project on behalf of its international partners. Those partners include Astronomy Australia Ltd., the Australian National University, the Carnegie Institution for Science, Harvard University, the Korea Astronomy and Space Science Institute, the Smithsonian Institution, Texas A&M University, the University of Arizona, The University of Texas at Austin, and the University of Chicago. For more information, visit www.gmto.org.

The Carnegie Institution for Science (carnegieScience.edu) has been a pioneering force in basic scientific research since 1902. It is a private, nonprofit organization with six research departments throughout the U.S. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.

As one of the world’s leading research institutions, Texas A&M University (http://www.tamu.edu) is in the vanguard in making significant contributions to the storehouse of knowledge, including that of science and technology. Research conducted at Texas A&M represents an annual investment of more than $630 million, which ranks third nationally for universities without a medical school, and underwrites approximately 3,500 sponsored projects. That research creates new knowledge that provides basic, fundamental and applied contributions resulting in many cases in economic benefits to the state, nation, and world.
 

A Solar System Family Portrait, from the Inside Out

The MESSENGER spacecraft has captured the first portrait of our Solar System from the inside looking out. Comprised of 34 images, the mosaic provides a complement to the Solar System portrait – that one from the outside looking in – taken by Voyager 1 in 1990.

“Obtaining this portrait was a terrific feat by the MESSENGER team,” says MESSENGER Principal Investigator Sean Solomon, of the Carnegie Institution of Washington. “This snapshot of our neighborhood also reminds us that Earth is a member of a planetary family that was formed by common processes four and a half billion years ago. Our spacecraft is soon to orbit the innermost member of the family, one that holds many new answers to how Earth-like planets are assembled and evolve.”

MESSENGER’s Wide Angle Camera (WAC) captured the images on November 3 and 16, 2010. In the mosaic, all of the planets are visible except for Uranus and Neptune, which – at distances of 3.0 and 4.4 billion kilometers – were too faint to detect. Earth’s Moon and Jupiter’s Galilean satellites (Callisto, Ganymede, Europa, and Io) can be seen in the NAC image insets. The Solar System’s perch on a spiral arm of the Milky Way galaxy also afforded a beautiful view of a portion of the galaxy in the bottom center.

“The curved shape of the mosaic is due to the inclination of MESSENGER’s orbit from the ecliptic, the plane in which Earth and most planets orbit, which means that the cameras must point up to see some planets and down to see others,” explains MESSENGER imaging team member Brett Denevi of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. “ The images are stretched to make it easier to detect the planets, though this stretch also highlights light scattered off of the planet limbs, and in some cases creates artifacts such as the non-spherical shape of some planets.”

Assembling this portrait was no easy feat, says Solomon. “It’s not easy to find a moment when many of the planets are within a single field of view from that perspective, and we have strong Sun-pointing constraints on our ability to image in some directions.”

APL’s Hong Kang, from MESSENGER’s guidance and control team, used the Jet Propulsion Laboratory’s Solar System Simulator to pinpoint the relative positions of MESSENGER and the planets to determine if it was possible to see the planets from MESSENGER at any given time. “I then used the celestial coordinates of the planets at the time I wanted to observe them to verify with simulations that MESSSENGER could see each of the planets,” Kang explains. “I also used a satellite tool kit to verify that we had the planets in the field of view of MESSENGER’s Mercury Dual Imaging System.”

The MESSENGER team then had to determine how long the exposures needed to be for each planet. “From exposure times that worked for previous imaging of stars with visual magnitudes similar to those of the planets, we chose exposure times that would allow us to obtain the appropriate number of counts (i.e., amount of light) in each planet image,” explains APL’s Nori Laslo, the mission’s Operations Lead and Instrument Sequencer for MDIS.

“We decided to take images using both the Narrow Angle Camera and the Wide Angle Camera for each planet so that we would cover the sky surrounding the planets and also image the planets themselves at as high a resolution as possible,” she adds. “I took all of these parameters, along with a variety of related settings, and began building the command sequence with the library of MDIS commands that we have to configure and control the camera system.”

Robin Vaughan, who worked with Kang to coordinate the pointing and timing of the MDIS, also played a role in Voyager’s portrait.

“I was working as an optical navigation analyst at JPL for the Voyager Neptune encounter,” says Vaughan, the lead engineer for MESSENGER's guidance and control (attitude control) subsystem at APL. “I had to plan and generate the pointing commands for pictures of Neptune and its satellites against background stars that we used to improve our estimate of the spacecraft’s trajectory leading up to the Neptune encounter. Voyager’s solar system portrait was done a few years after that flyby and was coordinated by the imaging team. Our optical navigation image planning software was used to double check the pointing commands they had designed and confirm what they expected to see in each image.”

Vaughan did the same thing for MESSENGER’s portrait, using Kang’s designs. “I used the SPICE trajectory files for the spacecraft generated by MESSENGER’s navigation team, as well as routines in the SPICE toolkit, to write a software program that would identify windows when each of the planets would be visible to MDIS given the...

Hubble Sees Farther Back in Time Than Ever Before

Pasadena, CA— Astronomers have pushed NASA’s Hubble Space Telescope to it limits by finding what they believe to be the most distant object ever seen in the universe—at a distance of 13.2 billion light years, some 3% of the age of universe. This places the object roughly 150 million light years more distant than the previous record holder. The observations provide the best insights yet into the birth of the first stars and galaxies and the evolution of the universe. The research is published in the 27th January edition of Nature.

The dim object is a compact galaxy made of blue stars that existed only 480 million years after the Big Bang. It is tiny. Over one hundred such mini galaxies would be needed to make up our Milky Way.

Co-author Ivo Labbé of the Carnegie Observatories puts the findings into context: “We are thrilled to have discovered this galaxy, but we’re equally surprised to have found only one. This tells us that the universe was changing very rapidly in early times.”

Previous searches had found 47 galaxies at somewhat later times, when the universe was about 650 million years old. The rate of star birth therefore increased by about ten times in the interval from 480 million years to 650 million years. “This is an astonishing increase in such a short period, happening in just 1% of the age of the universe,” says Labbé.

“These observations provide us with our best insights yet into the earliest primeval objects yet to be found,” adds Rychard Bouwens of the University of Leiden in the Netherlands.

Astronomers don’t know exactly when the first stars appeared in the universe, but every step back in time takes them deeper into the early universe’s “formative years” when stars and galaxies were just beginning to emerge in the aftermath of the Big Bang.

“We’re moving into a regime where there are big changes afoot. And what it tells us is that if we go back another couple hundred million years toward the Big Bang we’ll see absolutely dramatic things happening. That will be the time where the first galaxies really are starting to get built up,” says Garth Illingworth of the University of California at Santa Cruz.

The even more distant proto galaxies will require the infrared vision of NASA’s James Webb Space Telescope, which is the successor to Hubble, and next-generation ground-based telescopes, such as the Giant Magellan Telescope. These new facilities, planned for later this decade, will provide confirming spectroscopic measurements of the tremendous distance of the object being reported today.

After over a year of detailed analysis, the galaxy was positively identified in the Hubble Ultra Deep Field – Infrared (HUDF-IR) data taken in the late summer of both 2009 and 2010. These observations were made with the Wide Field Planetary Camera 3 (WFPC3) starting just a few months after it was installed into the Hubble Space Telescope in May of 2009, during the last NASA space shuttle servicing mission to Hubble.

The object appears as a faint dot of starlight in the Hubble exposures. It is too young and too small to have the familiar spiral shape that is characteristic of galaxies in the local universe, such as the Milky Way. Though individual stars can’t be resolved by Hubble, the evidence suggests that this is a compact galaxy of hot stars that first started to form over 100 to 200 million years earlier in a pocket of dark matter.

The proto galaxy is only visible at the farthest infrared wavelengths observable by Hubble. This means that the expansion of the universe has stretched its light farther that any other galaxy previously identified in the HUDF-IR, to the very limit of Hubble’s capabilities.

Astronomers plumb the depths of the universe by measuring how much the light from an object has been stretched by the expansion of space. This is called redshift value or “z.” Before Hubble was launched, astronomers could only see galaxies out to a z approximately 1, corresponding to 6 billion years after the Big Bang. The Hubble Deep Field taken in 1995 leapfrogged to z=4, or roughly 90 percent of the way back to the beginning of time. The new Advanced Camera and the Hubble Ultra Deep Field pushed back the limit to z~6 after the 2002 servicing mission. Hubble’s first infrared camera, the Near Infrared Camera and Multi Object Spectrometer reached out to z=7. The WFC3/IR reached back to z~8, and now plausibly has penetrated for the first time to z=10 (about 500 million years after the Big Bang). The Webb Space Telescope is expected to leapfrog to z~15, and possibly beyond. The very first stars may have formed between z of 30 to 15, or 100 to 250 million years post Big Bang.

The hypothesized hierarchical growth of galaxies—from stellar clumps to majestic spirals—didn’t become evident until the Hubble Space Telescope deep field exposures. The first 500 million years of the universe’s existence, from a z of 1000 to...

Carnegie’s Wendy Freedman Named AAAS Fellow

Washington, D.C.—Carnegie Observatories director Wendy Freedman has been selected as an AAAS Fellow by the American Association for the Advancement of Science. The announcement will appear Jan. 11 on the AAAS website and will be published in the “AAAS News & Notes” section of Science on Jan. 28.

The organization said it selected Freedman for her work calibrating the current expansion rate of the universe, and thereby calculating the age of the universe.

“We are honored that Wendy Freedman was chosen as a fellow,” said Carnegie president Richard Meserve. “She is a remarkable scientist with a body of work that is recognized throughout the world.”

The AAAS Fellows program dates back to 1874. This year the organization selected a total of 503 members for the honor for “their efforts toward advancing science applications that are deemed scientifically or socially distinguished.”

The new fellows will be presented with an official certificate and rosette pin on Feb. 19, at the AAAS Fellows Forum during the AAAS Annual Meeting in Washington, D.C.
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