NASA’s Swift Produces Best Ultraviolet Maps of the Nearest Galaxies
Astronomers at NASA and Pennsylvania State University have used NASA’s Swift satellite to create the most detailed ultraviolet light surveys ever of the Large and Small Magellanic Clouds, the two closest major galaxies.
“We took thousands of images and assembled them into seamless portraits of the main body of each galaxy, resulting in the highest-resolution surveys of the Magellanic Clouds at ultraviolet wavelengths,” said Stefan Immler, who proposed the program and led NASA’s contribution from the agency’s Goddard Space Flight Center in Greenbelt, Md.
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New surveys conducted by NASA’s Swift provide the most detailed overviews ever captured in ultraviolet light of the Large and Small Magellanic Clouds, the two closest major galaxies to our own. Swift team member Stefan Immler, who proposed the imaging project, narrates this quick tour.
Credit: NASA’s Goddard Space Flight Center › Download video in HD formats › Watch video on YouTube |
Immler presented a 160-megapixel mosaic image of the Large Magellanic Cloud (LMC) and a 57-megapixel mosaic image of the Small Magellanic Cloud (SMC)at the 222nd American Astronomical Society meeting in Indianapolis on Monday.
The new images reveal about 1 million ultraviolet sources in the LMC and about 250,000 in the SMC. The images include light ranging from 1,600 to 3,300 angstroms, which is a range of UV wavelengths largely blocked by Earth’s atmosphere.
UV image credit: NASA/Swift/S. Immler (Goddard) and M. Siegel (Penn State)
Visible image credit: Axel Mellinger, Central Michigan Univ.
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“Prior to these images, there were relatively few UV observations of these galaxies, and none at high resolution across such wide areas, so this project fills in a major missing piece of the scientific puzzle,” said Michael Siegel, lead scientist for Swift’s Ultraviolet/Optical Telescope (UVOT) at the Swift Mission Operations Center at the university in State College, Pa.
The LMC and SMC lie about 163,000 light-years and 200,000 light-years away, respectively, and orbit each other as well as our own Milky Way galaxy. The LMC is about one-tenth the size of the Milky Way and contains only 1 percent of the Milky Way’s mass. The SMC is half the size of the LMC and contains about two-thirds of its mass.
Despite their modest sizes, the galaxies loom large in the sky because they are so close to us. Both extend far beyond the UVOT’s field of view, which meant thousands of images were needed in order to cover both galaxies in three ultraviolet colors centered at wavelengths of 1,928 angstroms, 2,246 angstroms, and 2,600 angstroms.
Credit: Axel Mellinger, Central Michigan Univ.
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Viewing in the ultraviolet allows astronomers to suppress the light of normal stars like the sun, which are not very bright at such higher energies, and provides a clearer picture of the hottest stars and star-formation regions. No telescope other than UVOT can produce such high-resolution wide-field multicolor surveys in the ultraviolet. Swift’s wide-field imaging capabilities provide a powerful complement to the deeper, but much narrower-field imaging power of NASA’s Hubble Space Telescope.
Credit: NASA/Swift/S. Immler (Goddard) and M. Siegel (Penn State)
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To produce the 160-megapixel LMC mosaic, Swift’s UVOT acquired 2,200 snapshots for a cumulative exposure of 5.4 days. The 57-megapixel SMC image comprises 656 individual images with a total exposure of 1.8 days.
Both images have an angular resolution of 2.5 arc seconds, which is a measure of their sharpness. Sources separated by this angle, which is equivalent to the size of a dime seen from 1mile away, are visible as distinct objects.
“With these mosaics, we can study how stars are born and evolve across each galaxy in a single view, something that’s very difficult to accomplish for our own galaxy because of our location inside it,” Immler said.
The Large and Small Magellanic Clouds are readily visible from the Southern Hemisphere as faint, glowing patches in the night sky. The galaxies are named after Ferdinand Magellan, the Portuguese explorer who in 1519 led an expedition to sail around the world. He and his crew were among the first Europeans to sight the objects.
Pennsylvania State University manages the Swift Mission Operations Center, which controls Swift’s science and flight operations. Goddard manages Swift, which was launched in November 2004. The satellite is operated in collaboration with Penn State, the Los Alamos National Laboratory in New Mexico and Orbital Sciences Corp. in Dulles, Va. International collaborators are in the United Kingdom and Italy, and the mission includes contributions from Germany and Japan.
Hubble Peers Through a Spacetime Magnifying Glass
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This Hubble image shows the galaxy cluster Abell S1077. Galaxy clusters are large groupings of galaxies, each of them including millions of stars. They are the largest existing structures in the Universe to be held together by their gravity.
The amount of matter condensed in such groupings is so high that their gravity is enough to warp the fabric of spacetime, distorting the path that light takes when it travels through the cluster. In some cases, this phenomenon produces an effect somewhat like a magnifying lens, allowing us to see objects that are aligned behind the cluster and which would otherwise be undetectable from Earth. In this image, you see stretched stripes that look like scratches on a lens but are, in fact, galaxies whose light is heavily distorted by the gravitational field of the cluster.
Astronomers use tools like the NASA/ESA Hubble Space Telescope and the effects of gravitational lensing to peer far back in time and space to see the furthest objects located in the early Universe. One of the record holders is MACS0647-JD, a galaxy seen by Hubble and the Spitzer Space Telescope with the help of a gravitational lens much like this one in the galaxy cluster MACS J0647.7+7015. Its light has taken 13.3 billion years to reach us.
Hubble Reveals the Ring Nebula’s True Shape
Credit: NASA, ESA, C.R. Robert O’Dell (Vanderbilt University), G.J. Ferland (University of Kentucky), W.J. Henney and M. Peimbert (National Autonomous University of Mexico)
Credit for Large Binocular Telescope data: David Thompson (University of Arizona)
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The Ring Nebula’s distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA’s Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star reveal a new twist.
“The nebula is not like a bagel, but rather, it’s like a jelly doughnut, because it’s filled with material in the middle,” said C. Robert O’Dell of Vanderbilt University in Nashville, Tenn. He leads a research team that used Hubble and several ground-based telescopes to obtain the best view yet of the iconic nebula. The images show a more complex structure than astronomers once thought and have allowed them to construct the most precise 3-D model of the nebula.
This planetary nebula’s simple, graceful appearance is thought to be due to perspective: our view from Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star. Hot blue gas near the energizing central star gives way to progressively cooler green and yellow gas at greater distances with the coolest red gas along the outer boundary. Credit: NASA/Hubble Heritage Team
› Larger image “With Hubble’s detail, we see a completely different shape than what’s been thought about historically for this classic nebula,” O’Dell said. “The new Hubble observations show the nebula in much clearer detail, and we see things are not as simple as we previously thought.”
The Ring Nebula is about 2,000 light-years from Earth and measures roughly 1 light-year across. Located in the constellation Lyra, the nebula is a popular target for amateur astronomers.
Previous observations by several telescopes had detected the gaseous material in the ring’s central region. But the new view by Hubble’s sharp-eyed Wide Field Camera 3 shows the nebula’s structure in more detail. O’Dell’s team suggests the ring wraps around a blue, football-shaped structure. Each end of the structure protrudes out of opposite sides of the ring.
The nebula is tilted toward Earth so that astronomers see the ring face-on. In the Hubble image, the blue structure is the glow of helium. Radiation from the white dwarf star, the white dot in the center of the ring, is exciting the helium to glow. The white dwarf is the stellar remnant of a sun-like star that has exhausted its hydrogen fuel and has shed its outer layers of gas to gravitationally collapse to a compact object.
O’Dell’s team was surprised at the detailed Hubble views of the dark, irregular knots of dense gas embedded along the inner rim of the ring, which look like spokes in a bicycle wheel. These gaseous tentacles formed when expanding hot gas pushed into cool gas ejected previously by the doomed star. The knots are more resistant to erosion by the wave of ultraviolet light unleashed by the star. The Hubble images have allowed the team to match up the knots with the spikes of light around the bright, main ring, which are a shadow effect. Astronomers have found similar knots in other planetary nebulae.
All of this gas was expelled by the central star about 4,000 years ago. The original star was several times more massive than our sun. After billions of years converting hydrogen to helium in its core, the star began to run out of fuel. It then ballooned in size, becoming a red giant. During this phase, the star shed its outer gaseous layers into space and began to collapse as fusion reactions began to die out. A gusher of ultraviolet light from the dying star energized the gas, making it glow.
The outer rings were formed when faster-moving gas slammed into slower-moving material. The nebula is expanding at more than 43,000 miles an hour, but the center is moving faster than the expansion of the main ring. O’Dell’s team measured the nebula’s expansion by comparing the new Hubble observations with Hubble studies made in 1998.
The Ring Nebula will continue to expand for another 10,000 years, a short phase in the lifetime of the star. The nebula will become fainter and fainter until it merges with the interstellar medium.
Studying the Ring Nebula’s fate will provide insight into the sun’s demise in another 6 billion years. The sun is less massive than the Ring Nebula’s progenitor star, so it will not have an opulent ending.
“When the sun becomes a white dwarf, it will heat more slowly after it ejects its outer gaseous layers,” O’Dell said. “The material will be farther away once it becomes hot enough to illuminate the gas. This larger distance means the sun’s nebula will be fainter because it is more extended.”
In the analysis, the research team also obtained images from the Large Binocular Telescope at the Mount Graham International Observatory in Arizona and spectroscopic data from the San Pedro Martir Observatory in Baja California, Mexico.
Hubble Sees a Swirl of Star Formation
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This beautiful, glittering swirl is named, rather un-poetically, J125013.50+073441.5. A glowing haze of material seems to engulf the galaxy, stretching out into space in different directions and forming a fuzzy streak in this image. It is a starburst galaxy — a name given to galaxies that show unusually high rates of star formation. The regions where new stars are being born are highlighted by sparkling bright blue regions along the galactic arms.
Studying starburst galaxies can tell us a lot about galactic evolution and star formation. These galaxies start off with huge amounts of gas, which is used to form new stars. This period of furious star formation is only a phase; once all the gas is used up, this star birth slows down. Other famous starbursts captured by Hubble include the Antennae Galaxies and Messier 82, the latter of which is forming new stars ten times faster than our galaxy, the Milky Way.
The data for this image were collected using Hubble’s Wide Field Camera 3 as part of a study named LARS (Lyman Alpha Reference Sample), which is investigating the interaction between radiation and matter in relatively nearby starburst galaxies.
European Space Agency/NASA Hubble
Over 3000 K-12 Students Connected with NASA Airborne Science Program Missions During the 2012-2013 School Year
One hundred and sixty-four K-12 classrooms from across the United States and Chile with 3030 total students participated in online chats with Airborne Science Program mission personnel in the field during the 2012/2013 school year.
Mission Tools Suite for Education is a unique website that allows students and teachers to connect directly with ongoing Airborne Science research campaigns. The Mission Tools Suite (MTS) is web-based software used by mission personnel to monitor and assist with real-time decision making during the course of an Airborne Science mission. The Airborne Science Program has created a scaled down version of the tool called MTS for Education (MTSE), which is aimed at supporting core K-12 classroom science curriculum.
The NASA Airborne Science Program’s Mission Tools Suite for Education website allows K-12 classrooms from around the world to track the locations of NASA aircraft in real-time and participate in live text-chats with mission scientists, pilots, and others flying inside the airplanes and with mission personnel on the ground. Website features include:
- • Live flight following
– Students and teachers can track the position of ASP aircraft on a map in real-time
- • Live camera feeds from the aircraft (on select missions)
- • Real-time satellite data products
– Overlay current weather, hurricane tracks, etc
- • Environmental data from the aircraft
– Ability to plot aircraft altitude, speed, temperature, wind speed, etc. in real-time
- • Live text chats between classrooms and mission scientists, pilots, and others onboard the aircraft or on the ground
The website has so far been used during five NASA Airborne Science Program missions in 2012-2013
- • Hurricane and Severe Storm Sentinel (Sept 2012)
- • IceBridge Antarctic (Oct-Nov 2012)
- • DISCOVER-AQ (Jan-Feb 2013)
- • ATTREX (Feb-Mar 2013)
- • IceBridge Arctic (Mar-May 2013)
From Kindergarteners asking if IceBridge personnel saw Santa when they flew over the North Pole (they did not), to middle school students asking what it feels like to fly a Global Hawk over a hurricane without actually being inside it during HS3, to high school students asking specific questions about atmospheric chemistry during DISCOVER-AQ and ATTREX, classroom chats are effective at all grade levels.
“Our 3rd graders were enthralled with following Operation IceBridge. They loved learning about the science of the mission from those on the airplane, and were fascinated with Antarctica, and learned a lot about ice shelves, glaciers, and much more. Over the course of the year, they study all the continents, so the area covered by the flights gave them an opportunity to be introduced to Google Earth and use it to explore South America and Antarctica. Kudos to Operation Icebridge for including students in their mission. Thanks to all involved.”
–Cameron Cross, 3rd Grade Teacher, New Hampshire
Hubble Sees the Messy Result of a Galactic Collision
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This new image from the NASA/ESA Hubble Space Telescope captures an ongoing cosmic collision between two galaxies — a spiral galaxy is in the process of colliding with a lenticular galaxy. The collision looks almost as if it is popping out of the screen in 3-D, with parts of the spiral arms clearly embracing the lenticular galaxy’s bulge.
The image also reveals further evidence of the collision. There is a bright stream of stars coming out from the merging galaxies, extending out towards the top of the image. The bright spot in the middle of the plume, known as ESO 576-69, is what makes this image unique. This spot is believed to be the nucleus of the former spiral galaxy, which was ejected from the system during the collision and is now being shredded by tidal forces to produce the visible stellar stream.
Landsat 8 Satellite Begins Watch
WASHINGTON — NASA transferred operational control Thursday of the Landsat 8 satellite to the U.S. Geological Survey (USGS) in a ceremony in Sioux Falls, S.D.
The event marks the beginning of the satellite’s mission to extend an unparalleled four-decade record of monitoring Earth’s landscape from space. Landsat 8 is the latest in the Landsat series of remote-sensing satellites, which have been providing global coverage of landscape changes on Earth since 1972. The Landsat program is a joint effort between NASA and USGS.
NASA launched the satellite Feb. 11 as the Landsat Data Continuity Mission (LDCM). Since then, NASA mission engineers and scientists, with USGS collaboration, have been putting the satellite through its paces — steering it into its orbit, calibrating the detectors, and collecting test images. Now fully mission-certified, the satellite is under USGS operational control.
“Landsat is a centerpiece of NASA’s Earth Science program,” said NASA Administrator Charles Bolden in Washington. “Landsat 8 carries on a long tradition of Landsat satellites that for more than 40 years have helped us learn how Earth works, to understand how humans are affecting it and to make wiser decisions as stewards of this planet.”
Beginning Thursday, USGS specialists will collect at least 400 Landsat 8 scenes every day from around the world to be processed and archived at the USGS Earth Resources Observation and Science Center in Sioux Falls. The newest satellite joins Landsat 7, which launched in 1999 and continues to collect images. Since 2008, USGS has provided more than 11 million current and historical Landsat images free of charge to users over the Internet.
“We are very pleased to work with NASA for the good of science and the American people,” said U.S. Interior Secretary Sally Jewell in Washington. “The Landsat program allows us all to have a common, easily accessible view of our planet. This is the starting point for a shared understanding of the environmental challenges we face.”
Remote-sensing satellites such as the Landsat series help scientists observe the world beyond the power of human sight, monitor changes to the land that may have natural or human causes, and detect critical trends in the conditions of natural resources.
The 41-year Landsat record provides global coverage at a scale that impartially documents natural processes such as volcanic eruptions, glacial retreat and forest fires and shows large-scale human activities such as expanding cities, crop irrigation and forest clear-cuts. The Landsat Program is a sustained effort by the United States to provide direct societal benefits across a wide range of human endeavors including human and environmental health, energy and water management, urban planning, disaster recovery, and agriculture.
With Landsat 8 circling Earth 14 times a day, and in combination with Landsat 7, researchers will be able to use an improved frequency of data from both satellites. The two observation instruments aboard Landsat 8 feature improvements over their earlier counterparts while collecting information that is compatible with 41 years of land images from previous Landsat satellites.
For more information about the Landsat mission, visit:
Dragon Arrives With Treasure Trove of Science
The SpaceX Dragon cargo vehicle is berthed to the International Space Station’s Harmony module. Image credit: NASA TV
The International Space Station welcomed its second contracted cargo delivery flight Sunday with the arrival of the SpaceX Dragon carrying a treasure trove of science cargo, hardware and supplies for the Expedition 34 crew.
Controlling the 57.7-foot Canadarm2 from a robotics workstation inside the station’s cupola, Commander Kevin Ford, with assistance from Flight Engineer Tom Marshburn, grappled the SpaceX Dragon cargo craft at 5:31 a.m. EST as it flew within about 32 feet of the complex. Flight Engineer Chris Hadfield joined Ford and Marshburn in the cupola to assist with the capture and help coordinate the activities. The station was flying 253 statute miles above northern Ukraine at the time of capture.
› View video of Dragon grapple
Upon successful completion of the grapple, Ford congratulated SpaceX and the ground teams supporting the mission and remarked, “As they say, it’s not where you start, but where you finish that counts, and you guys really finished this one on the mark. You’re aboard, and we’ve got lots of science on there to bring aboard and get done.”
With Dragon securely in the grasp of Canadarm2, the robotics officer at Mission Control remotely operated the arm to install the capsule to its port on the Earth-facing side of the Harmony module. Once Dragon was in place, Ford monitored the Common Berthing Mechanism operations for first and second stage capture of the cargo ship, assuring that the vehicle was securely attached to the station with a tight seal. Second stage capture was completed at 8:56 a.m.
Running well ahead of the timeline, Marshburn opened the hatch to Dragon at 1:14 p.m., enabling Ford and Hadfield to enter the cargo craft a little more than four hours after Dragon was berthed to the station following a flawless rendezvous. Ford and Hadfield will begin to unload Dragon’s cargo on Monday morning.
The SpaceX Falcon 9 rocket, with its Dragon spacecraft onboard, lifts off from Launch Complex 40 at the Cape Canaveral Air Force Station in Florida. Image credit: NASA TV
Dragon is scheduled to spend more than three weeks attached to the station. During that time, the crew will unload around 1,200 pounds of science cargo, station hardware and crew supplies from the craft and reload it with more than 2,600 pounds of experiment samples and equipment for return to Earth.
After Dragon’s mission at the station is completed, the crew will use Canadarm2 to detach Dragon from Harmony on March 25 and release it for a parachute-assisted splashdown in the Pacific Ocean about 300 miles west of the coast of Baja California.
Dragon launched atop a Falcon 9 rocket at 10:10 a.m. Friday from Cape Canaveral Air Force Station in Florida, beginning the second of 12 SpaceX flights contracted by NASA to resupply the station. This marks the third visit by a Dragon capsule to the orbiting laboratory, following a demonstration flight in May 2012 and its first commercial resupply mission in October 2012.
Dragon’s rendezvous with the station was delayed a day in the wake of a temporary loss of three of four banks of thrusters after Dragon separated from the Falcon 9 rocket Friday.
A Window into Europa’s Ocean Right at the Surface
This illustration of Europa (foreground), Jupiter (right) and Io (middle) is an artist’s concept. Image credit: NASA/JPL-Caltech
This view of Jupiter’s moon Europa features several regional-resolution mosaics overlaid on a lower resolution global view for context. Image credit: NASA/JPL-Caltech/University of Arizona
If you could lick the surface of Jupiter’s icy moon Europa, you would actually be sampling a bit of the ocean beneath. A new paper by Mike Brown, an astronomer at the California Institute of Technology in Pasadena, Calif., and Kevin Hand from NASA’s Jet Propulsion Laboratory, also in Pasadena, details the strongest evidence yet that salty water from the vast liquid ocean beneath Europa’s frozen exterior actually makes its way to the surface.
The finding, based on some of the best data of its kind since NASA’s Galileo mission (1989 to 2003) to study Jupiter and its moons, suggests there is a chemical exchange between the ocean and surface, making the ocean a richer chemical environment. The work is described in a paper that has been accepted for publication in the Astronomical Journal.
The exchange between the ocean and the surface, Brown said, “means that energy might be going into the ocean, which is important in terms of the possibilities for life there. It also means that if you’d like to know what’s in the ocean, you can just go to the surface and scrape some off.”
Europa’s ocean is thought to cover the moon’s whole globe and is about 60 miles (100 kilometers) thick under a thin ice shell. Since the days of NASA’s Voyager and Galileo missions, scientists have debated the composition of Europa’s surface. The infrared spectrometer aboard Galileo was not capable of providing the detail needed to identify definitively some of the materials present on the surface. Now, using the Keck II Telescope on Mauna Kea, Hawaii, and its OSIRIS spectrometer, Brown and Hand have identified a spectroscopic feature on Europa’s surface that indicates the presence of a magnesium sulfate salt, a mineral called epsomite, that could have formed by oxidation of a mineral likely originating from the ocean below.
Brown and Hand started by mapping the distribution of pure water ice versus anything else. The spectra showed that even Europa’s leading hemisphere contains significant amounts of non-water ice. Then, at low latitudes on the trailing hemisphere—the area with the greatest concentration of the non-water ice material—they found a tiny, never-before-detected dip in the spectrum.
The two researchers tested everything from sodium chloride to Drano in Hand’s lab at JPL, where he tries to simulate the environments found on various icy worlds. At the end of the day, the signature of magnesium sulfate persisted.
The magnesium sulfate appears to be generated by the irradiation of sulfur ejected from the Jovian moon Io and, the authors deduce, magnesium chloride salt originating from Europa’s ocean. Chlorides such as sodium and potassium chlorides, which are expected to be on the Europa surface, are in general not detectable because they have no clear infrared spectral features. But magnesium sulfate is detectable. The authors believe the composition of Europa’s ocean may closely resemble the salty ocean of Earth.
Europa is considered a premier target in the search for life beyond Earth, Hand said. A NASA-funded study team led by JPL and the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., has been working with the scientific community to identify options to explore Europa further. “If we’ve learned anything about life on Earth, it’s that where there’s liquid water, there’s generally life,” Hand said. “And of course our ocean is a nice, salty ocean. Perhaps Europa’s salty ocean is also a wonderful place for life.”
The work was supported, in part, by the NASA Astrobiology Institute through the Icy Worlds team based at JPL, a division of Caltech. The NASA Astrobiology Institute, based at NASA’s Ames Research Center, Moffett Field, Calif., is a partnership among NASA, 15 U.S. teams, and 13 international consortia. The NAI is part of NASA’s Astrobiology program, which supports research into the origin, evolution, distribution and future of life on Earth and the potential for life elsewhere.
Happening in Da U.P.? Great Lakes Radio Pix!
