January 13, 2010, 7:45 AM CT

First Comprehensive Sky Map

Ever since NASA's Interstellar Boundary Explorer, or IBEX, mission researchers released the first comprehensive sky map of our solar system's edge in particles, solar physicists have been busy revising their models to account for the discovery of a narrow "ribbon" of bright emission that was completely unexpected and not predicted by any model at the time.

Further study by a team of researchers funded through NASA's Heliophysics Guest Investigator program has produced a revised model that explains and closely reproduces the IBEX result by incorporating a single new effect into an existing model. The new effect, put forward by the IBEX team soon after sighting of the ribbon, is that the magnetic field surrounding our solar systemcalled the local galactic magnetic fieldacts like a mirror for the particles that IBEX sees.

The results appear in the January 10 issue of the Astrophysical Journal Letters Jacob Heerikhuisen, a solar physicist at the University of Alabama in Huntsville, is the main author of the paper. Heerikhuisen and colleagues believe the orientation of the local galactic magnetic field is closely correlation to the location of the ribbon in the sky.

Charged particles "orbit" magnetic field lines. When they suddenly lose their charge, they fly off in a straight line maintaining their current direction. Only particles that orbit the magnetic mirror, where it faces us directly, can flow back toward us and are captured by IBEX......... Posted by: Sean      Read more         Source

January 11, 2010, 8:04 AM CT

Fossil fireballs from supernovae

Studies of two supernova remnants using the Japan-U.S. Suzaku observatory have revealed never-before-seen embers of the high-temperature fireballs that immediately followed the explosions. Even after thousands of years, gas within these stellar wrecks retain the imprint of temperatures 10,000 times hotter than the sun's surface.

"This is the first evidence of a new type of supernova remnant -- one that was heated right after the explosion," said Hiroya Yamaguchi at the Institute of Physical and Chemical Research in Japan.

A supernova remnant commonly cools quickly due to rapid expansion following the explosion. Then, as it sweeps up tenuous interstellar gas over thousands of years, the remnant gradually heats up again.

Capitalizing on the sensitivity of the Suzaku satellite, a team led by Yamaguchi and Midori Ozawa, a graduate student at Kyoto University, detected unusual features in the X-ray spectrum of IC 443, better known to amateur astronomers as the Jellyfish Nebula.

The remnant, which lies some 5,000 light-years away in the constellation Gemini, formed about 4,000 years ago. The X-ray emission forms a roughly circular patch in the northern part of the visible nebulosity.

Suzaku's X-ray Imaging Spectrometers (XISs) separate X-rays by energy in much the same way as a prism separates light into a rainbow of colors. This allows astronomers to tease out the types of processes responsible for the radiation......... Posted by: Sean      Read more         Source

January 6, 2010, 8:15 AM CT

Galactic GPS

Radio astronomers have uncovered 17 millisecond pulsars in our galaxy by studying unknown high-energy sources detected by NASA's Fermi Gamma-ray Space Telescope. The astronomers made the discovery in less than three months. Such a jump in the pace of locating these hard-to-find objects holds the promise of using them as a kind of "galactic GPS" to detect gravitational waves passing near Earth.

A pulsar is the rapidly spinning and highly magnetized core left behind when a massive star explodes. Because only rotation powers their intense gamma-ray, radio and particle emissions, pulsars gradually slow as they age. But the oldest pulsars spin hundreds of times per second -- faster than a kitchen blender. These millisecond pulsars have been spun up and rejuvenated by accreting matter from a companion star.

"Radio astronomers discovered the first millisecond pulsar 28 years ago," said Paul Ray at the Naval Research Laboratory in Washington. "Locating them with all-sky radio surveys requires immense time and effort, and we've only found a total of about 60 in the disk of our galaxy since then. Fermi points us to specific targets. It's like having a treasure map".

Millisecond pulsars are nature's most precise clocks, with long-term, sub-microsecond stability that rivals human-made atomic clocks. Precise monitoring of timing changes in an all-sky array of millisecond pulsars may allow the first direct detection of gravitational waves -- a long-sought consequence of Einstein's relativity theory......... Posted by: Sean      Read more         Source

January 6, 2010, 8:12 AM CT

A Sun Glint on Earth

n two new videos from NASA's Deep Impact spacecraft, bright flashes of light known as sun glints act as beacons signaling large bodies of water on Earth. These observations give scientists a way to pick out planets beyond our solar system (extrasolar planets) that are likely to have expanses of liquid, and so stand a better chance of having life.

These sun glints are like sunshine glancing off the hood of a car. We can see them reflecting off a smooth surface when we are positioned in just the right way with respect to the sun and the smooth surface. On a planetary scale, only liquids and ice can form a surface smooth enough to produce the effectland masses are too roughand the surface must be very large. To stand out against a background of other radiation from a planet, the reflected light must be very bright. We won't necessarily see glints from every distant planet that has liquids or ice.

"But these sun glints are important because, if we saw an extrasolar planet which had glints that popped up periodically, we would know that we were seeing lakes, oceans or other large bodies of liquid, such as water," says Drake Deming, of NASA's Goddard Space Flight Center in Greenbelt, Md. Deming is the deputy principal investigator who leads the team that works on the Extrasolar Planet Observations and Characterization (EPOCh) part of Deep Impact's extended mission, called EPOXI. "And if we found large bodies of water on a distant planet, we would become much more optimistic about finding life"......... Posted by: Sean      Read more         Source

January 6, 2010, 8:06 AM CT

New mathematical model for early universe

Researchers have made a number of discoveries about the origins of our 13 billion-year-old universe. But a number of scientific mysteries remain. What exactly happened during the Big Bang, when rapidly evolving physical processes set the stage for gases to form stars, planets and galaxies? Now astrophysicists using supercomputers to simulate the Big Bang have a new mathematical tool to unravel those mysteries, says Daniel R. Reynolds, assistant professor of mathematics at SMU.

Reynolds collaborated with astrophysicists at the University of California at San Diego as part of a National Science Foundation project to simulate cosmic reionization, the time from 380,000 years to 400 million years after the universe was born.

Together the researchers built a computer model of events during the "Dark Ages" when the first stars emitted radiation that altered the surrounding matter, enabling light to pass through. The team tested its model on two of the largest existing NSF supercomputers, "Ranger" at the University of Texas at Austin and "Kraken" at the University of Tennessee.

The new mathematical model tightly couples a myriad of physical processes present during cosmic reionization, such as gas motion, radiation transport, chemical kinetics and gravitational acceleration due to star clustering and dark matter dynamics, Reynolds says......... Posted by: Sean      Read more         Source

December 18, 2009, 6:59 PM CT

Fog on Titan

Saturn's largest moon, Titan, looks to be the only place in the solar systemaside from our home planet, Earthwith copious quantities of liquid (largely, liquid methane and ethane) sitting on its surface. As per planetary astronomer Mike Brown of the California Institute of Technology (Caltech), Earth and Titan share yet another feature, which is inextricably linked with that surface liquid: common fog.

The presence of fog provides the first direct evidence for the exchange of material between the surface and the atmosphere, and thus of an active hydrological cycle, which previously had only been known to exist on Earth.

In a talk to be delivered December 18 at the American Geophysical Union's 2009 Fall Meeting in San Francisco, Brown, the Richard and Barbara Rosenberg Professor and professor of planetary astronomy, details evidence that Titan's south pole is spotted "more or less everywhere" with puddles of methane that give rise to sporadic layers of fog. (Technically, fog is just a cloud or bank of clouds that touch the ground).

Brown and colleagues also describe their findings in a recent paper published in The Astrophysical Journal Letters

The scientists made their discovery using data from the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft, which has been observing Saturn's system for the past five years......... Posted by: Sean      Read more         Source

December 11, 2009, 7:53 AM CT

VISTA: Pioneering new survey telescope

VISTA is the latest telescope to be added to ESO's Paranal Observatory in the Atacama Desert of northern Chile. It is housed on the peak adjacent to the one hosting the ESO Very Large Telescope (VLT) and shares the same exceptional observing conditions. VISTA's main mirror is 4.1 metres across and is the most highly curved mirror of this size and quality ever made its deviations from a perfect surface are less than a few thousandths of the thickness of a human hair and its construction and polishing presented formidable challenges.

VISTA was conceived and developed by a consortium of 18 universities in the United Kingdom [1] led by Queen Mary, University of London and became an in-kind contribution to ESO as part of the UK's accession agreement. The telescope design and construction were project-managed by the Science and Technology Facilities Council's UK Astronomy Technology Centre (STFC, UK ATC). Provisional acceptance of VISTA was formally granted by ESO at a ceremony at ESO's Headquarters in Garching, Gera number of, attended by representatives of Queen Mary, University of London and STFC, on 10 December 2009 and the telescope will now be operated by ESO.

"VISTA is a unique addition to ESO's observatory on Cerro Paranal. It will play a pioneering role in surveying the southern sky at infrared wavelengths and will find a number of interesting targets for further study by the Very Large Telescope, ALMA and the future European Extremely Large Telescope," says Tim de Zeeuw, the ESO Director General......... Posted by: Sean      Read more         Source

December 10, 2009, 10:29 PM CT

Super-massive black holes

An international team of researchers has observed four super-massive black holes at the center of galaxies, which may provide new information on how these central black hole systems operate. Their findings appear in December's first issue of the journal Astronomy and Astrophysics

These super-massive black holes at the center of galaxies are called active galactic nuclei. For the first time, the team observed a quasar with an active galactic nucleus, as part of the group of four, which is located more than a billion light years from Earth. The researchers used the two Keck telescopes on top of Mauna Kea in Hawaii. These are the largest optical/infrared telescopes in the world.

The team also used the United Kingdom Infrared Telescope (UKIRT) to follow up the Keck observations, to obtain current near-infrared images of the target galaxies.

"Astronomers have been trying to see directly what exactly is going on in the vicinity of these accreting super-massive black holes," said co-author Robert Antonucci, a UC Santa Barbara astrophysicist.

He explained that the nuclei of a number of galaxies show intense radiation from X-ray to optical, infrared, and radio, where the nucleus may exhibit a strong jet a linear feature carrying particles and magnetic energy out from a central super-massive black hole. Researchers believe these active nuclei are powered by accreting super-massive black holes. The accreting gas and dust are particularly bright in the optical and infrared regions of the electromagnetic spectrum......... Posted by: Sean      Read more         Source

December 9, 2009, 11:34 PM CT

Brightest-Ever Blazar Flare

A galaxy located billions of light-years away is commanding the attention of NASA's Fermi Gamma-ray Space Telescope and astronomers around the globe. Thanks to a series of flares that began September 15, the galaxy is now the brightest source in the gamma-ray sky -- more than ten times brighter than it was in the summer.

Astronomers identify the object as 3C 454.3, an active galaxy located 7.2 billion light-years away in the constellation Pegasus. But even among active galaxies, it's exceptional.

"We're looking right down the barrel of a particle jet powered by the galaxy's supermassive black hole," said Gino Tosti at the National Institute of Nuclear Physics in Perugia, Italy. "Some change within that jet -- we don't know what -- is likely responsible for these flares."

Blazars, like a number of active galaxies, emit oppositely directed jets of particles traveling near the speed of light when matter falls toward their central supermassive black holes. What makes a blazar so bright in gamma rays is its orientation: One of the jets happens to be aimed straight at us.

Most of the time, the brightest persistent source in the gamma-ray sky is the Vela pulsar, which at a distance of about 1,000 light-years lies practically next door.

"3C 454.3 is millions of times farther away, yet the current flare makes it twice as bright as Vela," said Lise Escande at the Center for Nuclear Studies in Gradignan, near Bordeaux, France. "That represents an incredible energy release, and one the source can't sustain for very long."........ Posted by: Sean      Read more         Source

December 8, 2009, 8:02 AM CT

NRL's MISSE7 l

The Materials on the International Space Station Experiment (MISSE) 7, designed and built by the Naval Research Laboratory (NRL), launched aboard STS-129 on November, 16, for transport to the International Space Station.

MISSE7 consists of two Passive Experiment Carriers (PEC7a and PEC7b) and three experiments mounted to the Express Pallet Assembly (ExPA). The individual experiments on MISSE7 include in situ monitoring of materials exposure, environmental monitoring including temperature, atomic oxygen exposure, and ionizing radiation. "The results will provide a better understanding of the durability of advanced materials and electronics when they are exposed to vacuum, solar radiation, atomic oxygen, and extremes of heat and cold," explains Mr. Phillip Jenkins, principal investigator. These materials and electronics, including solar cells, coatings, thermal protection, optics, sensors, and computing elements, have the potential to increase the performance and useful life of the next generation of satellites and launch systems.

NRL is responsible for the overall hardware integration and operation of MISSE7, including the power and data interfaces between the ISS and over 20 experiments included on MISSE7. NRL designed and built the power supply and thermal control system. The Communications Interface Board (CIB), which serves as the communication link between the ISS and the MISSE7 experiments, was designed, built, programmed and delivered to NRL by the Mobile And Remote Sensing (MARS) Lab at NASA GRC. Individual experiments that make up MISSE7 include researchers from NASA, DoD, DOE and university derived experiments. MISSE7 was integrated and flown under the direction of DoD's Space Test Program. NRL scientists from the Spacecraft Engineering Department and Electronics Science & Technology Division worked in conjunction on the MISSE7 project......... Posted by: Sean      Read more         Source