Astronomers Uncover A Surprising Trend in Galaxy Evolution

NASA - Hubble Space Telescope patch. / W. M. Keck Observatory logo.

Oct. 19, 2012

Video above: A study of 544 star-forming galaxies observed by the Keck and Hubble telescopes shows that disk galaxies like our own Milky Way unexpectedly reached their current state long after much of the universe's star formation had ceased. Over the past 8 billion years, the galaxies lose chaotic motions and spin faster as they develop into settled disk galaxies. Credit: NASA's Goddard Space Flight Center.

A comprehensive study of hundreds of galaxies observed by the Keck telescopes in Hawaii and NASA's Hubble Space Telescope has revealed an unexpected pattern of change that extends back 8 billion years, or more than half the age of the universe.

"Astronomers thought disk galaxies in the nearby universe had settled into their present form by about 8 billion years ago, with little additional development since," said Susan Kassin, an astronomer at NASA's Goddard Space Flight Center in Greenbelt, Md., and the study's lead researcher. "The trend we've observed instead shows the opposite, that galaxies were steadily changing over this time period."

Today, star-forming galaxies take the form of orderly disk-shaped systems, such as the Andromeda Galaxy or the Milky Way, where rotation dominates over other internal motions. The most distant blue galaxies in the study tend to be very different, exhibiting disorganized motions in multiple directions. There is a steady shift toward greater organization to the present time as the disorganized motions dissipate and rotation speeds increase. These galaxies are gradually settling into well-behaved disks.

Graphic above: This plot shows the fractions of settled disk galaxies in four time spans, each about 3 billion years long. There is a steady shift toward higher percentages of settled galaxies closer to the present time. At any given time, the most massive galaxies are the most settled. More distant and less massive galaxies on average exhibit more disorganized internal motions, with gas moving in multiple directions, and slower rotation speeds. Credit: NASA's Goddard Space Flight Center.

Blue galaxies -- their color indicates stars are forming within them -- show less disorganized motions and ever-faster rotation speeds the closer they are observed to the present. This trend holds true for galaxies of all masses, but the most massive systems always show the highest level of organization.

Researchers say the distant blue galaxies they studied are gradually transforming into rotating disk galaxies like our own Milky Way.

"Previous studies removed galaxies that did not look like the well-ordered rotating disks now common in the universe today," said co-author Benjamin Weiner, an astronomer at the University of Arizona in Tucson. "By neglecting them, these studies examined only those rare galaxies in the distant universe that are well-behaved and concluded that galaxies didn't change."

Rather than limit their sample to certain galaxy types, the researchers instead looked at all galaxies with emission lines bright enough to be used for determining internal motions. Emission lines are the discrete wavelengths of radiation characteristically emitted by the gas within a galaxy. They are revealed when a galaxy's light is separated into its component colors. These emission lines also carry information about the galaxy's internal motions and distance.

Simulations such as this will help astronomers better understand the new findings in galaxy evolution. It tracks the development of a single disk galaxy from shortly after the Big Bang to the present day. Colors reveal old stars (red), young stars (white and bright blue) and the distribution of gas density (pale blue); the view is 300,000 light-years across. Credit: F. Governato and T. Quinn (Univ. of Washington), A. Brooks (Univ. of Wisconsin, Madison), and J. Wadsley (McMaster Univ.).

The team studied a sample of 544 blue galaxies from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Redshift Survey, a project that employs Hubble and the twin 10-meter telescopes at the W. M. Keck Observatory in Hawaii. Located between 2 billion and 8 billion light-years away, the galaxies have stellar masses ranging from about 0.3 percent to 100 percent of the mass of our home galaxy.

A paper describing these findings will be published Oct. 20 in The Astrophysical Journal.

The Milky Way galaxy must have gone through the same rough-and-tumble evolution as the galaxies in the DEEP2 sample, and gradually settled into its present state as the sun and solar system were being formed.

In the past 8 billion years, the number of mergers between galaxies large and small has decreased sharply. So has the overall rate of star formation and disruptions of supernova explosions associated with star formation. Scientists speculate these factors may play a role in creating the evolutionary trend they observe.

Now that astronomers see this pattern, they can adjust computer simulations of galaxy evolution until these models are able to replicate the observed trend. This will guide scientists to the physical processes most responsible for it.

The DEEP2 survey is led by Lick Observatory at the University of California at Santa Cruz in collaboration with the University of California at Berkeley, the University of Hawaii at Manoa, Johns Hopkins University in Baltimore, Md., the University of Chicago and the California Institute of Technology in Pasadena.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy, Inc. in Washington.

Related Links:

› NASA's Hubble website: http://www.nasa.gov/hubble

› Narrated video on the NASA Explorer YouTube channel: http://youtu.be/voq3Wfr5cho

› Cosmology simulation video on the NASA Explorer YouTube channel: https://www.youtube.com/watch?v=_Ssc1GsqHds

› Download videos and other visuals in broadcast quality: http://svs.gsfc.nasa.gov/goto?11087

› Paper: The Epoch of Disk Settling: z ~ 1 to Now. doi:10.1088/0004-637X/758/2/106: http://iopscience.iop.org/0004-637X/758/2/106

› Talk by Susan Kassin at the University of California High-Performance Astrocomputing Center: http://hipacc.ucsc.edu/Talk_single.php?Tid=242&SerId=20&Aid=20

› The Deep Extragalactic Evolutionary Probe project: http://deep.ucolick.org/

› University of California High-Performance AstroComputing Center press release: http://hipacc.ucsc.edu/GalaxyDiskSettling.html

Image (mentioned), Videos (mentioned), Text, Credit: NASA's Goddard Space Flight Center / Francis Reddy.

Greetings, Orbiter.ch

ESA Science Programme’s new small satellite will study super-Earths

ESA - Cheops Mission poster.


19 October 2012

Studying planets around other stars will be the focus of the new small Science Programme mission, Cheops, ESA announced today. Its launch is expected in 2017.

Cheops – for CHaracterising ExOPlanets Satellite – will target nearby, bright stars already known to have planets orbiting around them.

Through high-precision monitoring of the star’s brightness, scientists will search for the telltale signs of a ‘transit’ as a planet passes briefly across its face.

In turn, this will allow an accurate measurement of the radius of the planet. For those planets with a known mass, the density will be revealed, providing an indication of the internal structure.

Artist impression of Cheops

These key parameters will help scientists to understand the formation of planets from a few times the mass of the Earth – ‘super-Earths’ – up to Neptune-sized worlds.

It will also identify planets with significant atmospheres and constrain the migration of planets during the formation and evolution of their parent systems. 

Cheops is the first of a possible new class of small missions to be developed as part of ESA’s Science Programme.

“By concentrating on specific known exoplanet host stars, Cheops will enable scientists to conduct comparative studies of planets down to the mass of Earth with a precision that simply cannot be achieved from the ground,” said Professor Alvaro Giménez-Cañete, ESA Director of Science and Robotic Exploration.

“The mission was selected from 26 proposals submitted in response to the Call for Small Missions in March, highlighting the strong interest of the scientific community in dedicated, quick-turnaround missions focusing on key open issues in space science.”

Planet transit in front of a star

Possible future small missions in the Science Programme should be low cost and rapidly developed, in order to offer greater flexibility in response to new ideas from the scientific community.

With a dedicated science focus, they would provide a natural complement to the broader Medium- and Large-class missions of ESA’s Science Programme.

Cheops will be implemented as a partnership between ESA and Switzerland, with a number of other ESA Member States delivering substantial contributions.

“This continues the 40-year success story of Swiss scientists and industry at the forefront of space science,” said Professor Willy Benz, Center for Space and Habitability at the University of Bern.

The mission will also provide unique targets for more detailed studies of exoplanet atmospheres by the next generation of telescopes now being built, such as the ground-based European Extremely Large Telescope and the NASA/ESA/CSA James Webb Space Telescope.

Cheops will operate in a Sun-synchronous low-Earth orbit at an altitude of 800 km. It has a planned mission lifetime of 3.5 years and part of the observing time will be open to the wider scientific community.

Related links:

Defining the Cosmic Vision: http://www.esa.int/esaSC/SEMNNJ2IU7E_index_0.html

Missions beyond imagination: http://www.esa.int/esaSC/SEM8OJ2IU7E_index_0.html

Cosmic Vision in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=100

Bern University - Cheops Homepage: http://cheops.unibe.ch/

Credits: ESA / University of Bern / CNES.

Best regards, Orbiter.ch

Mars Soil Sample Delivered for Analysis Inside Rover

NASA - Mars Science Laboratory (MSL) patch.

Oct. 18, 2012

Mission Status Report

Image above: Three bite marks left in the Martian ground by the scoop on the robotic arm of NASA's Mars rover Curiosity are visible in this image taken by the rover's right Navigation Camera during the mission's 69th Martian day, or sol (Oct. 15, 2012). Image Credit: NASA/JPL-Caltech/MSSS.

NASA's Mars rover Curiosity has ingested its first solid sample into an analytical instrument inside the rover, a capability at the core of the two-year mission.

The rover's Chemistry and Mineralogy (CheMin) instrument is analyzing this sample to determine what minerals it contains.

"We are crossing a significant threshold for this mission by using CheMin on its first sample," said Curiosity's project scientist, John Grotzinger of the California Institute of Technology in Pasadena. "This instrument gives us a more definitive mineral-identifying method than ever before used on Mars: X-ray diffraction. Confidently identifying minerals is important because minerals record the environmental conditions under which they form."

Image above: The robotic arm on NASA's Mars rover Curiosity delivered a sample of Martian soil to the rover's observation tray for the first time during the mission's 70th Martian day, or sol (Oct. 16, 2012). Image Credit: NASA/JPL-Caltech/MSSS.

The sample is a sieved portion -- about as much material as in a baby aspirin -- from the third scoop collected by Curiosity as a windblown patch of dusty sand called "Rocknest." The rover's robotic arm delivered the sample to CheMin's opened inlet funnel on the rover's deck on Oct. 17.

The previous day, the rover shook the scooped material inside sample-processing chambers to scrub internal surfaces of any residue carried from Earth. One earlier scoopful was also used for cleaning. Additional repetitions of this cleaning method will be used before delivery of a future sample to the rover's other internal analytic instrument, the Sample Analysis at Mars investigation, which studies samples' chemistry.

Various small bits of light-toned material on the ground at Rocknest have affected the rover's activities in the past several days. One piece about half an inch (1.3 centimeters) long was noticed on Oct. 7. The rover team postponed use of the robotic arm for two days while investigating this object, and assessed it to be debris from the spacecraft.

This image shows part of the small pit or bite created when NASA's Mars rover Curiosity collected its second scoop of Martian soil at a sandy patch called "Rocknest." Image credit: NASA/JPL-Caltech/MSSS.

Images taken after Curiosity collected its second scoop of Rocknest material on Oct. 12 showed smaller bits of light-toned material in the hole dug by the scooping action. This led to discarding that scoopful rather than using it to scrub the processing mechanisms. Scientists assess these smaller, bright particles to be native Martian material, not from the spacecraft.

Mars Science Laboratory (MSL) "Curiosity". Image credit: NASA/JPL-Caltech

"We plan to learn more both about the spacecraft material and about the smaller, bright particles," said Curiosity Project Manager Richard Cook of NASA's Jet Propulsion Laboratory, Pasadena. "We will finish determining whether the spacecraft material warrants concern during future operations. The native Mars particles become fodder for the mission's scientific studies."

During a two-year prime mission, researchers are using Curiosity's 10 instruments to assess whether the study area has ever offered environmental conditions favorable for microbial life. JPL, a division of Caltech, manages the project and built Curiosity. For more about Curiosity, visit: http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl .

You can follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity and http://www.twitter.com/marscuriosity .

Images (mentioned), Video (mentioned), Text, Credits: NASA / JPL / Guy Webster.

Greetings, Orbiter.ch

How Space Station Can Help Humans Follow Curiosity to Mars and Beyond

ISS - International Space Station patch.

Oct. 18, 2012

With all of the excitement of the Mars Curiosity landing, many are looking to move from robots to humans for exploration beyond Earth's orbit. Keeping in mind the Seven Minutes of Terror, just imagine the nail-biting moments of putting people into the harsh environment of space far from their home planet. Taking the guess work out of long-duration exploration, however, is one of the benefits of the International Space Station. This orbiting laboratory serves as a test bed for technology and helps researchers understand how to prepare for extended trips in space.

"The space station is so valuable in this effort because it provides so much of what encompasses a long-duration transit mission, but with the convenience and lower risk of being located in low Earth orbit," said George Nelson, manager of International Space Station Technology Demonstration with NASA.

Image above: NASA astronaut Andrew Feustel, STS-134 mission specialist, installs the Materials on International Space Station Experiment – 8, or MISSE-8, hardware. MISSE-8 is a test bed for materials and computing elements attached to the outside of the International Space Station. (NASA).

Communications is one of the concerns that the space station can assist with, as delays of radio and telemetry information between the crew and mission control increase the further a vehicle gets from the Earth. Current space station operations rely on fast and almost continuous voice, data, command, and telemetry transmissions with controllers on the ground. Mars missions, however, could have up to a 20-minute delay in sending and receiving data. While the timing varies from destination to destination, the approach to preparing for continued operations is the same.

Astronauts need proven procedures for how to operate independently from mission control. Aboard station, the crew practices countermeasures for delays by operating certain activities with self-enforced lapses in communications. For instance, in the summer of 2012 astronauts successfully performed preventative maintenance on the COLBERT on-orbit treadmill while purposely not speaking with flight controllers. This is a step in the right direction for creating autonomy.

Image above: The Amine Swingbed assembly, shown here, is a life-support technology undergoing testing aboard the International Space Station. (NASA).

"The operations community has recently worked to revise many space station crew procedures to eliminate the need for communication with the ground," said Nelson. "We are currently testing some of these revised procedures on station to verify that they can be performed effectively. In addition, we are attempting new procedure formats, uplinked videos for instance, that may be even more effective."

The Materials International Space Station Experiment, or MISSE, series of investigations also helps with the development of protective materials. These advances may safeguard future vehicles and crew against things like radiation, extreme temperatures, atomic oxygen, and sunlight. The samples fly for set durations of time in direct contact with the space environment, prior to returning to the ground for testing.

Maintaining a safe living area in space requires technology advances not only for vehicle exteriors, but for inside as well. Researchers and engineers continually look to find better ways to provide a crew with clean, sustainable air and water. For instance, aboard the station the Environmental Control and Life Support System, or ECLSS, advances scientific understanding and design elements to improve future closed-loop life support systems.

Image above: NASA's Hubble Space Telescope took this close-up of Mars, the Red Planet, when it was just 34,648,840 miles (55,760,220 kilometers) away from Earth. Mars is just one of the potential destinations for long duration exploration that may benefit from the use of the International Space Station as a technology test bed. (NASA).

Other benefits of this on-orbit testing include greater efficiency, design improvements to reduce equipment mass, and accelerated technology developments thanks to longer trial periods in microgravity. One new life support technology currently undergoing testing aboard station is the Amine Swingbed. This equipment is designed to remove carbon dioxide from the living space inside the modules of the orbiting laboratory. When humans take in oxygen, they breathe out carbon dioxide, which needs to be scrubbed from the air to ensure continued crew health. This system is more compact and runs on less power than its predecessors.

International Space Station (ISS). (NASA)

"Testing of various life support systems is an ideal use of the space station," said Nelson. "Reliability of these systems on long distance/duration missions is paramount. We can verify design reliability in the microgravity environment by using them on station without any mission or crew risk, since the existing systems are always available."

The Curiosity of humanity may have reached Mars first, but it is our continued innovations and testing, like those done aboard the space station, that will help people follow the lander to the Red Planet and beyond.

Related Links:

Mars Curiosity: http://www.nasa.gov/mission_pages/msl/index.html

Mars Science Laboratory (MSL) landing animation - Seven Minutes of Terror: http://www.youtube.com/watch?v=Ki_Af_o9Q9s

COLBERT: http://www.nasa.gov/mission_pages/station/research/experiments/COLBERT.html

MISSE: http://www.nasa.gov/mission_pages/station/research/experiments/MISSE-8.html

ECLSS: http://en.wikipedia.org/wiki/ISS_ECLSS

Amine Swingbed: http://www.nasa.gov/mission_pages/station/research/experiments/Amine_Swingbed.html

Images (mentioned), Text, Credits: NASA's Johnson Space Center / Jessica Nimon.

Best regards, Orbiter.ch

Curiosity - Rover's Second Scoop Discarded, Third Scoop Commanded

NASA - Mars Science Laboratory (MSL) patch.

Oct. 17, 2012

This image contributed to an interpretation by NASA's Mars rover Curiosity science team that some of the bright particles on the ground near the rover are native Martian material. Other light-toned material nearby (see PIA16230) has been assessed as small debris from the spacecraft. Image Credit: NASA/JPL-Caltech/MSSS.

 Commands will be sent to Curiosity today instructing the rover to collect a third scoop of soil from the "Rocknest" site of windblown Martian sand and dust. Pending evaluation of this Sol 69 (Oct. 15, 2012) scooping, a sample from the scoopful is planned as the first sample for delivery -- later this week -- to one of the rover's internal analytical instruments, the Chemistry and Mineralogy (CheMin) instrument. A later scoopful will become the first solid sample for delivery to the rover's other internal analytical instrument, the Sample Analysis at Mars (SAM) instrument.

This image from the Mars Hand Lens Imager (MAHLI) camera on NASA's Mars rover Curiosity shows a small bright object on the ground beside the rover at the "Rocknest" site. The object is just below the center of this image. It is about half an inch (1.3 centimeters) long. The rover team has assessed this object as debris from the spacecraft, possibly from the events of landing on Mars. Image Credit: NASA/JPL-Caltech/MSSS.

The rover's second scoopful, collected on Sol 66 (Oct. 12), was intentionally discarded on Sol 67 due to concern about particles of bright material seen in the hole dug by the scooping. Other small pieces of bright material in the Rocknest area have been assessed as debris from the spacecraft. The science team did not want to put spacecraft material into the rover's sample-processing mechanisms. Confidence for going ahead with the third scooping was based on new assessment that other bright particles in the area are native Martian material. One factor in that consideration is seeing some bright particles embedded in clods of Martian soil. Further investigations of the bright particles are planned, including some imaging in the Sol 69 plan.

Mars Science Laboratory (MSL). Image Credit: NASA/JPL-Caltech

Sol 69, in Mars local mean solar time at Gale Crater, will end at 5:01 a.m. Oct. 16, PDT (8:01 a.m., EDT).

  Here's the Scoop!

Video above: Curiosity shakes up a scoopful of dirt, dusts off the sampling system and investigates a shiny object on the surface of Mars. Credit: NASA/JPL-Caltech.

Curiosity's latest images are available at: http://1.usa.gov/MfiyD0

For more about NASA's Curiosity mission, visit: http://www.nasa.gov/mars and http://marsprogram.jpl.nasa.gov/msl

Follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity and http://www.twitter.com/marscuriosity

Images (mentioned), Video (mentioned), Text, Credits: NASA / JPL / Guy Webster.

Greetings, Orbiter.ch

Radioactive decay of titanium powers supernova remnant

ESA - Integral Mission patch.

17 October 2012

The first direct detection of radioactive titanium associated with supernova remnant 1987A has been made by ESA’s Integral space observatory. The radioactive decay has likely been powering the glowing remnant around the exploded star for the last 20 years.

ESA’s Integral space observatory in orbit

Stars are like nuclear furnaces, continuously fusing hydrogen into helium in their cores. When stars greater than eight times the mass of our Sun exhaust their hydrogen fuel, the star collapses. This may generate temperatures high enough to create much heavier elements by fusion, such as titanium, iron, cobalt and nickel.

After the collapse, the star rebounds and a spectacular supernova explosion results, with these constituent elements flung into space.

 Supernova remnant 1987A

Supernovae can shine as brightly as entire galaxies for a very brief time thanks to the enormous amount of energy released in the explosion.

After the initial flash has faded, the total luminosity of the remnant is provided by the release of energy from the natural decay of radioactive elements produced in the explosion.

Each element emits energy at some characteristic wavelengths as it decays, providing insight into the chemical composition of the supernova ejecta – the shells of material flung out by the exploding star. 

Supernova 1987A, located in one of the Milky Way’s nearby satellite galaxies, the Large Magellanic Cloud, was close enough to be seen by the naked eye when its light first reached Earth in February 1987.

Ti-44 detection in SNR 1987A

During the peak of the explosion, fingerprints of elements from oxygen to calcium were detected, representing the outer layers of the ejecta.

Soon after, signatures of the material synthesised in the inner layers could be seen in the radioactive decay of nickel-56 to cobalt-56, and its subsequent decay to iron-56.

Now, thanks to more than 1000 hours of observation by Integral, high-energy X-rays from radioactive titanium-44 in supernova remnant 1987A have been detected for the first time.

“This is the first firm evidence of titanium-44 production in supernova 1987A and in an amount sufficient to have powered the remnant over the last 20 years,” says Sergei Grebenev from the Space Research Institute of the Russian Academy of Science in Moscow, and the first author of the paper reporting the results in Nature.

From their analysis of the data, the astronomers estimated that the total mass of titanium-44 that must have been produced just after the core collapse of SN1987A’s progenitor star amounted to 0.03% of the mass of our own Sun.

Searching for Ti-44

This value is near the upper boundary of theoretical predictions and is nearly twice the amount seen in supernova remnant Cas A, the only other remnant where titanium-44 has been detected.

“The high values of titanium-44 measured in Cas A and SNR1987A are likely produced in exceptional cases, favouring supernovae with an asymmetric geometry, and perhaps at the expense of the synthesis of heavier elements,” says Dr Grebenev.

“This is a unique scientific result obtained by Integral that represents a new constraint to be taken into account in future simulations for supernova explosions,” adds Chris Winkler, ESA’s Integral project scientist and co-author of the Nature paper.

“These observations are broadening our understanding of the processes involved during final stages of a massive star’s life.”

Link:

Integral in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=21

Images, Text, Credits: ESA/ Integral / IBIS–ISGRI / S. Grebenev et al. / Hubble & NASA.

Cheers, Orbiter.ch

CERN - A summer of (physics) code

CERN - European Organization for Nuclear Research logo.

16 October 2012

 Servers at the CERN Data Centrre (Image: CERN)

Anyone in the world with a computer can contribute to research at CERN. Through the LHC@Home project, volunteers can offer up spare computing power to simulate and process collisions happening inside the Large Hadron Collider.

CERN LHC - To discover the secrets of the Universe

CERN recently improved the program with a new feature that helps scientists monitor the system that distributes work among volunteers’ computers. But the new feature is not the work of a CERN employee; it is the work of a college undergraduate who had the chance to work with CERN through the 2012 Google Summer of Code.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 20 Member States.

Read more:

Symmetry breaking: A summer of (physics code): http://www.symmetrymagazine.org/article/october-2012/a-summer-of-physics-code

Related links:

LHC@Home project: http://lhcathome.web.cern.ch/LHCathome/

Large Hadron Collider: http://public.web.cern.ch/public/en/LHC/HowLHC-en.html

2012 Google Summer of Code: http://code.google.com/soc/

Images, Text, Credit: CERN.

Greetings, Orbiter.ch