Water Not Flowing On Mars

A new finding raises doubts about the 2006 report that the bright spots on Mars some gullies suggest that liquid water flowed down the gullies sometime since 1999.

"It includes pure liquid water," says lead author Jon D. Pelletier of the University of Arizona in Tucson.

Pelletier and his colleagues used topographic data from the images of Mars from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Since 2006, HiRISE was the most detailed pictures ever of Mars from orbit.

The researchers applied basic research in physics, as the fluid flows under the conditions of Mars, as a stream of pure liquid water would look like in the HiRISE images over how an avalanche of dry granular debris such as sand and gravel would be.

"The dry granular case was the winner," says Pelletier, UA associate professor of Geosciences. "I was surprised. I began to think we would prove it is liquid water."

Finding liquid water on the surface of Mars would mean the best seats to current life on Mars, says co-author Alfred S. McEwen, a professor of UA Planetary Sciences.

"What we hope to do was due to the dry-flow model, but that has not happened," said McEwen, HiRISE principal investigator and director of UA's Planetary Image Research Laboratory.

An avalanche of dry debris is a much better match for their calculations and also what their computer model predicts, says Pelletier and McEwen.

Pelletier says: "Right now, the balance of evidence suggests that the dry granular case is the most likely."

They add that their research does not exclude that the pictures show, currents of very thick mud with about 50 percent to 60 percent of the sediment. Such mud would have a consistency similar to molasses or hot lava. From orbit, the resulting deposit would be similar to that of a dry avalanche.

In December 2006, Michael Malin and his colleagues published an article in the journal Science before the bright stripes formed that in two gullies Mars since 1999 "suggest that liquid water flowed on the surface of Mars during the last ten years."

Malin team used images from the Mars Global Surveyor Mars Orbital Camera (MOC) of water troughs, had before 1999. Repeat images of the gullies in 2006 showed bright stripes, which were not there in the earlier pictures.

Then Pelletier and McEwen were at a scientific meeting and began chatting about the amazing new knowledge. They discussed how much more detailed images from HiRISE could be used to meat from the Malin team findings.

Pelletier had experience in dealing with the stereoscopic computer-generated topographic maps known as digital elevation models (DEMs), to find out how special landscape.

DEMs with images of the landscape, from two different angles.
The Mars Reconnaissance Orbiter spacecraft will regularly point on targets so that high-resolution stereo images, says McEwen.

Kirk DM of a crater in the Centauri Montes region, where the Malin team found a new bright stripes in a gully.

Once the DM, Pelletier uses the topographic information together with a commercially available numerical computer model to predict, such as deposits in this particular gully would appear, if a pure water compared to flood, the deposits appear as if they an avalanche dry.

The model also predicts specific conditions necessary to prevent any kind of debris flow.

"This is the first time that someone has applied for numerical computer models to the bright deposits in gullies on Mars or on DEMs produced by HiRISE images," says Pelletier.

When he compared the realities of the deposit and its bright HiRISE image to the predictions from the model, the dry avalanche model was a better fit.

"The dry granular case is simpler and largely complies with the observations," says Pelletier. "It is only a test. It's either more like one or more as b. We were surprised that it is more like B."

Pelletier, says these new findings show, "There are other ways to get deposits that look like these that did not require water."

One of the teams in the next steps with HiRISE images to examine similar bright deposits on less steep slopes to clarify what processes might have formed these deposits.

First Binocular Light Images

The Large Binocular Telescope on Mount Graham, Arizona has taken pictures with his heavenly twin side-by-side, 27.6 feet (8.4 meter) primary mirror, achieving first "binoculars" light.

U.S., Italian and German partners in the telescope, known as the LBT is the release of the pictures today. First binoculars light is a milestone not only for the LBT - now the world's most powerful telescope - but for astronomy itself, the partners say.

The first light binoculars images show three false-color rendition of the spiral galaxy NGC 2770th The galaxy is 102 million light years from year our Milky Way, a relatively close neighbours. The galaxy has a flat disk of stars and glowing gas and is slightly tilted in the direction of our line of sight.

The first picture combines ultraviolet and green light and stresses the clumpy regions of the newly formed hot stars in the spiral arms. The second image combines two dark red color in order to smooth the distribution of older, cooler stars. The third image is a composite of UV, green and deep red light and shows the detailed structure of the hot, temperate and cool stars in the galaxy. The cameras and pictures were taken by the major Binocular Camera team, led by Emanuele Giallongo in Rome Astrophysical Observatory.
The LBT is a light-gathering surface of a single 39-foot (11.8 meters) surfaces and light combined to achieve the sharpness corresponds to a single 75-foot (22.8 meters) telescope. It is located in 10480-foot Mount Graham in southeast Arizona.

"Being a fully functional binocular telescope is not only a time to celebrate here in the LBT, but also for the entire community of astronomy", UA Steward Observatory Director, Regents' professor and LBT Corp. President Peter A. Strittmatter says. "The pictures that the telescope will produce is not as previously seen. The strength and clarity of this machine is a class for itself. It offers unsurpassed-to-peer capability in the history since the birth of the universe."

Regents' Professor and Steward Observatory Mirror Lab Director Roger Angel was one of the UA astronomers designed the basic idea for the LBT in the early 1980s. The UA-Mirror Lab, known worldwide for breakthrough technologies mirror, occupation of the LBT mirror in its huge rotating oven and polished them with a unique technique stressed lap virtual perfection. Angel was previously involved in UA research, the development of adaptive optics technologies for the giant telescopes, technologies, the defeat of atmospheric turbulence.

"The LBT gives me the most satisfaction of all astronomy project I have worked, because it's very revolutionary, and because Arizona has the biggest and the best telescope in the world," says Angel. "If all parts are available, the LBT will be sharper images than any other telescope. I think it is the most likely telescope to the first pictures of planets around other stars, because of a unique advanced technologies used to build it."
International cooperation saw that the project to completion "is remarkable," says John P. Schaefer, chairman of the LBT Corp. Board of Directors and a member of the Research Group Corp. Board of Directors. "The LBT project was once only an idea, and now it is the world's most advanced telescope, developed by the international cooperation of more than 15 institutions. The completion of this one-of-a-kind instrument reflects what can happen when people come together towards a common goal. "

LBT Director Richard Green says: "The amount of time and effort to this project was to reach the point where we are today, is immense. We have, through challenging moments, but to see the telescope with the two operational level is a great feeling. Anyone who has worked on this, at all levels, is enormously proud of what has been achieved. "

Black Hole Sheds Light On Galaxy

A light echo occurs when interstellar gas is heated by radiation and reacts by emission of light. An international team led by Stefanie Komossa of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, the light echo an enormous X-ray flare, which was almost certainly produced when a single star was interrupted by a supermassive black Hole. For the first time, the light echo of such a rare and highly dramatic event could be observed in great detail. The light echo not only shown the stellar interference process, but it also offers a powerful new method for mapping galactic nuclei.

If a star is disrupted by a black hole at the core of a galaxy, the remains will inevitably attracted and absorbed from the black hole. This sudden increase in the accretion leads to a sudden burst of UV and X-ray light, because the gas from the star is disturbed very hot. As the high radiation travels through the core of the galaxy lights surrounding matter and thus makes it possible to probe regions of the galaxy, which would otherwise unobservable.

"To study the nucleus of a normal galaxy, as we look at the New York skyline at night during a power outage: You can not learn much about the buildings, streets and parks," said Stefanie Komossa. "The situation is changing, for example, while a fireworks display. It is exactly the same when a sudden burst of the high radiation of a galaxy is lit." However, the astronomers to hurry up and look through the telescope at the right time, since X-ray bursts is not very long.

From the strength, the level of ionization and the speeds derived from the rapidly changing emission lines, the physicists can tell which part of the galaxy, they are issued. The emission lines represent the "fingerprints" of the atoms in the hot gases heated by the flare. The galaxy catalog called SDSSJ0952 2143 was found in December 2007 by Komossa and her team in the Sloan Digital Sky Survey Archive caught their attention because of its superstrong iron lines: the strongest (relative to oxygen emission), the ever observed in a Galaxy. They are the authors is an indication of a molecular torus, plays an important role in the so-called unified models of active galaxies.

The Unified model posits that all active galaxies are made from identical components and the perceived differences are only due to the different directions from which the galaxies. An important element of this model is the molecular torus, which surrounds the black hole and its accretion disk and covers be, if they come from certain directions. The width of the spectral lines that scientists measure is influenced by the direction and the view is from the molecular torus.

If the expectations of Komossa and her colleagues confirmed, this will be the first time that scientists have seen a strong time-variable signal from a molecular torus. From the easy coverage, the torus can be mapped and its geometry deduce that something was not possible until today.

In the same vein is the detection of variable emission in the infrared band: It can be seen as the "last cry for help" of the heated dusty torus matter before the dust is destroyed by the flash.

In addition to the remarkably strong iron lines, the scientists also found a very peculiar form of hydrogen emission lines, had never before seen. This line information on activities of the disk of matter around the black hole, which consists mainly of hydrogen.

"Probably we will see the rubble disrupted the star is currently accreted from the black hole," says Zhou Hongyan from the MPE, co-author of the research paper.

The recently discovered light echo further and will be prosecuted with powerful telescopes. The burst itself has faded away. The first observations with the Chandra X-ray satellite show measurable already weak X-rays from the galactic core. "Reverberation mapping of light echoes opened new opportunities to study galaxies," concludes Komossa. The team will now use this method to the physical conditions in the circumnuclear material in active and non-active galaxies.

Saturn's Stormy Weather

As a powerful electrical storm rages on Saturn with lightning bolts 10,000 times stronger than lightning on Earth, the spacecraft Cassini will continue its 5-month wake of the dramatic events.

Scientists with NASA's Cassini-Huygens mission has been tracking the light visibly, lightning storm generation - the longest continuously monitored electrical storm always monitored by Cassini.

Saturn electrical storms resemble terrestrial thunderstorms, but in a much larger scale. Storms on Saturn have a diameter of thousands of kilometers (several thousand kilometers) and radio signals generated by their flashes are thousands of times more powerful than that of terrestrial thunderstorms.

Lightning flashes in the storm continued producing radio waves called Saturn electrostatic discharge, the radio and plasma wave science instrument on 27 first November 2007. Cassini's imaging cameras to monitor the location and appearance of the storm, first spotting it about a week later, on 6 December.

"The electrostatic radio outbursts and waxed to have lost intensity for a period of five months," said Georg Fischer, an employee at the radio and plasma wave science team at the University of Iowa, Iowa City. "We have similar storms in the years 2004 and 2006 that each lasted almost a month, but the storm is more far-lived. And it appeared after nearly two years in which we do not recognize storm electrical activity of Saturn."

The new storm is located in Saturn's southern hemisphere - in a region the nickname "Storm Alley" mission scientists - where the earlier storm were observed by Cassini.

"To see the storm, the imaging cameras to find the right place at the right time, and whenever our cameras can be found in the storm, the radio there are outbreaks," said Ulyana Dyudina, an ally of the Cassini Imaging Team at the California Institute of Technology in Pasadena.

Cassini's Radio plasma wave instrument recognizes the storm every time he turns in prospect, which happens every 10 hours and 40 minutes, the approximate length of a Saturn day. Every few seconds, the storm is a radio pulse lasting for about one tenth of a second, which is typical of lightning bolts and other electrical discharges. These radio waves are detected, even if the storm on the horizon as seen from Cassini, a result of diffraction of radio waves through the atmosphere of the planet.

Amateur astronomers have kept track of the storm over his 5-month term. "As Cassini's camera can not track the storm every day, the amateur data is invaluable," said Fischer. "I am in constant contact with astronomers from all over the world, the most important actors is Marc Delcroix and other observers from the French Astronomical Society, Ralf Vande Bergh from the Netherlands, Christopher Go of the Philippines and Trevor Barry of Australia."

The storm will probably durable provision of information on the processes of power-intensive Saturn bolts. Cassini scientists will continue to monitor Storm Alley as the seasons change, so the beginning of autumn in the southern hemisphere of the planet.

Mars' Cold Insides

New observations by NASA's Mars Reconnaissance Orbiter indicate that the crust and upper mantle of Mars are stiffer and colder than previously thought.

The results suggest any liquid water that may exist beneath the surface of the planet, and any living organisms in the water, it is lower than scientists had suspected.

"We've found that the rocky surface of Mars is not bend under the weight of the north polar ice cap," said Roger Phillips of the Southwest Research Institute. Phillips is the lead author of a new report this week in the online version of Science. "This means that the planet's interior is stiffer, and thus colder than we thought."

The discovery was with the instrument Shallow radar on the spacecraft, which has the most detailed images at the time of the interior layers of ice, sand and dust from which the north polar cap on Mars. The radar images show long, uninterrupted layers stretching up to 600 miles (1000 km), or about one fifth the length of the United States.
"In our first insight into the polar ice with the radar on Mars Reconnaissance Orbiter, we can clearly see stacks of the icy material, the history of Mars' climate," says Jeffrey Plaut of NASA's Jet Propulsion Laboratory. Plaut is a science team member and a co-author of the paper. "radar" opens up a new route for the study Mars' past. "

The radar images show a smooth, flat border between the ice sheet and the rocky Martian crust. On Earth, the weight of a similar stack of ice would lead to the surface of the planet SAG. The fact that the Mars surface is not bending means that their strong outer shell, or lithosphere, a combination of upper-crust and mantle must be very thick and cold.

"The lithosphere of a planet is the rigid part. On Earth, the lithosphere is the part that breaks during an earthquake," says Suzanne Smrekar, deputy Researchers for Mars Reconnaissance Orbiter at JPL. "The ability of radar to see through the ice sheet and noted that there was no bending of the lithosphere gives us a good idea of today's temperatures inside Mars for the first time."

Temperatures in the outer part of a rocky planets such as Mars increases with the depth in the direction of the interior. The thicker the lithosphere, the more the temperatures gradually rising. The discovery of a thicker Martian lithosphere therefore means that any liquid water lurking in the aquifer beneath the surface should be lower than previously calculated, where the temperatures are warmer. The scientists speculate that all life on Mars in connection with the deep aquifers would also have to be buried deep inside.

The radar images also show four zones of finely distance layers of ice and dust, separated by thick layers of almost pure ice. The scientists think this pattern of thick layers of ice-free represents cycles of climate change on Mars for a period of about one million years. These climate changes are variations in the tilt of the planet's rotation axis and the eccentricity of its orbit around the sun. The observations support the idea that the north polar ice cap is geologically active and relatively young, about 4 million years ago.

Earth's Laws Still Apply In Distant Universe

The laws of nature are the same in the distant universe, because it here on Earth, according to new research by an international team of astronomers, including Christian Henkel from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn. Their research, published June 20 in Science, shows that one of the major figures in physics theory, the electron-proton mass ratio is almost exactly the same in a galaxy 6 billion light years away, as in Earth's Laboratories approximately 1836.15.

According to Michael Murphy, Swinburne astrophysicist and lead author of the study, it is an important result, as many scientists debate whether the laws of nature may be at different times and in different places in the universe. "We were able to show that the laws of physics are the same in this galaxy halfway across the visible universe, because it here on earth," he says.

The astronomers determined that by an effective look back in time in a distant quasar, labelled B0218 +367. The quasar's light, which has 7.5 billion years to us, was partially absorbed by ammonia gas in an intervening galaxy. Not only is useful in most ammonia bathroom cleaning products, it is also an ideal molecule to test our understanding of physics in the distant universe. Spectroscopic observations of the ammonia molecule have been associated with the Effelsberg 100m radio telescope in 2 cm wavelength (red-shifted from the original wavelength of 1.3 cm). The wavelengths at which ammonia absorbed Radio Energy from the quasar are vulnerable to this specific number of nuclear physics, the electron-proton mass ratio.

"By comparing the absorption of ammonia with other molecules, we were able to determine that the value of the electron-proton mass ratio in this galaxy, and confirm that it is the same as on earth," says Christian Henkel from MPIfR, an expert in molecular spectroscopy and co-author of the study.

The astronomers' goal is to continue the examination of the laws of nature in so many different places and times in the universe as possible in order to see how well the laws of nature, in testing situations. You need to absorb more galaxies. The studied galaxy, B0218 +367, is the only destination for this type of research so far. There must be much more target galaxies, once the right telescopes to find them available.

According to Murphy, this problem could be overcome with the proposed Square Kilometer Array (SKA) telescope project. "The SKA is the largest and most ambitious international project telescope ever conceived. After completion, there will be a huge gathering, and will allow us to search for more absorbing galaxies." The situation of Ska, was shortlisted for the Western Australia or South Africa, will be announced within the next 2 years.

Through its research on the forces of nature, the astronomers also hope that you a window into the extra dimensions of space that many theoretical physicists believe exist.

Ice On Mars

Dice-size crumbs of bright material have vanished from inside a trench where they were photographed by NASA's Phoenix Mars Lander 4 days ago, convincing scientists that the material was frozen water that vaporized after digging exposed it. "It must be ice," Phoenix says principal investigator Peter Smith of the University of Arizona, Tucson. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice. There had been some question whether the material was bright salt. Salt can not do that." The chunks were left at the bottom of a trench informally called Dodo-Goldilocks when Phoenix's robotic arm that enlarged trench on June 15, during the 20th martian day, or sol, since landing.

Several were gone when Phoenix looked at the trench early today, on the 24th Sol Also early today, digging in a different trench, the robotic arm connected with a hard surface that has scientists excited about the prospect of next uncovering an icy layer. The Phoenix science team spent Tuesday analyzing new images and data successfully returned from the lander earlier in the day. Studying the initial findings from the new Snow White 2 trench, located to the right of Snow White 1, Ray Arvidson of Washington University in St. Louis, co-investigator for the robotic arm, says, "We have dug a trench and uncovered a hard layer at the same depth as the ice layer in our other trench. " On Sol 24, Phoenix extended the first trench in the middle of a polygon at the Wonderland site. While digging, the robotic arm came upon a firm layer, and after three attempts to dig further, the arm went into a holding position.

Such an action is expected when the robotic arm comes upon a hard surface. Meanwhile, the spacecraft team at Lockheed Martin Space Systems in Denver is preparing a software patch to send to Phoenix in a few days so scientific data can be saved onboard again overnight when needed. Because of a large amount duplicative a file-maintenance data generated by the spacecraft Tuesday, the team is taking the precaution of not storing data in science Phoenix's flash memory, and instead downlinking it at the end of every day, until the conditions that produced those duplicative data files are corrected. "We now understand what happened, and we can fix it with a software patch," says Phoenix Project Manager Barry Goldstein of NASA's Jet Propulsion Laboratory, Pasadena. "Our 3-month schedule has 30 days of margin for contingencies like this, and we have used only one contingency day out of 24 sols. The mission is well ahead of schedule. We are making excellent progress toward full mission success."
Dice-size crumbs of light materials have disappeared from the inside of a trench where they were photographed by NASA's Mars Lander Phoenix 4 days, to convince scientists that the material was frozen water evaporates that after digging.

"It must be ice," says Phoenix principal investigator Peter Smith of the University of Arizona, Tucson. "These small lumps disappear completely during the course of a few days, this is the perfect proof that there is ice. There were some question whether the material was bright salt. Salt can not."

The pieces remained at the bottom of a trench informally called Dodo-Goldilocks at Phoenix digging robotic arm extended on 15 June in the course of the 20th Martian day, or Sol, since the landing. Several were gone when Phoenix looked at the ditch this morning, over 24 Sol.

Also this morning, digging in another ditch, the robotic arm in connection with a hard surface, scientists are excited by the prospect of an afterlife detection icy layer.

The Phoenix team for scientific analysis Thursday new images and data successful return from the lander earlier in the day.

Studies of the first results from the new Snow White 2 ditch, is on the right side of Snow White 1, Ray Arvidson of Washington University in St. Louis, co-investigator for the robotic arm, said: "We have dug a ditch and discovered a hard layer in the same depth as the ice layer in our other ditch. "

On Sol 24, Phoenix extended the first trench in the middle of a polygon on the website Wonderland. While digging, the robotic arm was on a solid layer, and after three attempts to dig further, the arm was in a firm. Such action when the robot arm is based on a hard surface.

Meanwhile, the spacecraft team of Lockheed Martin Space Systems in Denver is preparing a software patch to send to Phoenix in a few days as scientific data can be stored on board again overnight, if necessary. Due to the large amount a double file maintenance data collected by the spacecraft Tuesday, the team takes the pension does not have the storage of data in science Phoenix flash memory, and instead downlinking it at the end of each day, until the conditions that produced the duplicate files are corrected.

"We understand now what happened, and we can fix it with a software patch," says Phoenix Project Manager Barry Goldstein of NASA's Jet Propulsion Laboratory, Pasadena. "Our 3-month plan has 30 days the margin for unforeseen events like this, and we only have one day of contingency sol-gel-24. The mission is well ahead of schedule. We are making excellent progress on the path to success Mission. "

Black Holes Stop Star Formation

Astronomers have obtained unprecedented observational evidence of the role that supermassive black holes play in ending star formation in galaxies. The report was presented by Dr Sugata Kaviraj of Oxford University, UK, yesterday at the American Astronomical Society Meeting in St Louis, Missouri. This result is of special interest because it provides new insights into the role of black holes in the formation and evolution of massive galaxies. A study by the Oxford scientists using ultraviolet light provides solid observational evidence that the stormy centers of galaxies powered by supermassive black holes - 'Active Galactic Nuclei (AGN) - take over from exploding stars (supernovae) as the main mechanism by which the gas that fuels star formation is dispersed, as galaxies reach a critical size of 10 billion times the mass of the Sun.

The results were recently published in the December 2007 issue of the Monthly Notices of the Royal Astronomical Society (Kaviraj et al. MNRAS, 2007, 382, 960). "Our models of galaxy formation are all based on the notion that Active Galactic Nuclei are involved in 'snuffing out' - quenching - star formation in galaxies which are too large for mechanisms based on supernovae to explain," says Sugata Kaviraj, Leverhulme-Beecroft Fellow in Astrophysics at Oxford University, UK, who led the research. "Astronomers believe that the jets produced by Active Galactic Nuclei are powerful enough to 'blow away' star-forming gas from even the largest galaxies but up until now we have not had solid observational evidence to back this up The jets produced by typical Active Galactic Nuclei would have enough energy to power ten billion stars like our Sun! Our study indicates, for the first time from a purely observational viewpoint, the relationship between the mass of a galaxy and whether supernovae or AGN play a dominant role in star formation quenching , "Says Kaviraj. The scientific team from Oxford University, UK and the University of Hertfordshire, UK studied a special class of post-starburst galaxies, which lack ongoing star formation but whose spectra indicate that they formed a substantial fraction of their stellar mass in the very recent past. A recent period of vigorous star formation in these galaxies has therefore been rapidly quenched, making these objects perfect test-beds to probe the quenching process. The galaxies studied in this work are, by cosmological standards, nearby, at distances of 1.5 billion light-years or less. Using a novel combination of ultraviolet data from the Galaxy Evolution Explorer (an orbiting space telescope launched by NASA in 2003) and optical data from the Sloan Digital Sky Survey (one of the largest observational surveys that uses a dedicated 2.5-meter telescope equipped with a 120 megapixel camera;), the scientists were able to measure the efficiency with which quenching takes place in individual galaxies with unprecedented accuracy. "The work is very timely," stresses Marc Sarzi, Research Fellow at the University of Hertfordshire and academic visitor at Oxford. "Post-starburst galaxies are extremely rare objects and it is only thanks to the large volume encompassed by the Sloan survey that we could harness a significant number of them." Kaviraj adds, "In the AGN regime, the quenching efficiency is expected to scale positively with galaxy mass, while in the supernova regime the opposite trend is expected. We also know that AGN become significantly more abundant in galaxies with masses above roughly 10 billion times the mass of the Sun. Our results demonstrate that the expected dichotomy in the relationship between efficiency and quenching galaxy mass is indeed borne out by the data, exactly across the threshold expected mass - 10 billion times the mass of the Sun!

" According to co-author Joe Silk, who is Savilian Professor of Astronomy at Oxford University and has pioneered the use of black holes in models of galaxy formation, "We simply do not understand the murky details of galaxy formation. Some form of 'feedback' is slowing down and quenching both star formation in nearby galaxies and the distant universe. These results point to the likely culprit being a combination of the effects of exploding stars and supermassive black holes, with black holes in dominating the massive galaxies, as envisaged in contemporary galaxy formation models ".

Quantifying the role that AGN play in quenching star formation is of prime importance to astrophysicists as it would enable them to calibrate their models of galaxy formation. While the observations used in this study were of nearby galaxies, the challenge now is to confirm these preliminary results and widen the scope of the work to include a representative sample of galaxies: this would include those that are much further away, dating back to the peak epoch of star formation some 10 billion years ago, when the Universe was only 25 percent of its current age! Efforts, led by Kaviraj, are underway to combine several large observational surveys that trace the evolution of the universe over the last 10 billion years, to study the properties of post-starburst galaxy populations. The research is expected to yield significant insights into the quenching process and provide valuable constraints on the currently accepted paradigm galaxy formation.

Astronomers have obtained unprecedented observations evidence of the role that supermassive black holes at the end star formation in galaxies. The report was by Dr. Sugata Kaviraj Oxford University, UK, yesterday at the American Astronomical Society Meeting in St. Louis, Missouri. This result is of particular interest because it provides new insights into the role of black holes in the formation and evolution of massive galaxies.

A study by scientists from Oxford with UV light provides a solid observations evidence that the storm centers of galaxies powered by supermassive black holes - Active Galactic Nuclei (AGN) - Acquisition of exploding stars (supernovae) as the main mechanism by the gas that fuels star formation is in free float, such as galaxies reach a critical size of 10 billion times the mass of the sun. The results were recently published in the December 2007 issue of the Monthly Notices of the Royal Astronomical Society (Kaviraj et al. MNRAS, 2007, 382, 960).

"Our models of galaxy formation are all based on the idea that Active Galactic Nuclei are in" snuffing out "- quenching - star formation in galaxies that are too large for the probation on the supernovae to explain," says Sugata Kaviraj, Leverhulme - Beecroft fellow in astrophysics at the University of Oxford, UK, led the research.

"The astronomers believe that the jets of active galactic nuclei are powerful enough to" blow away "star-forming gas from even the largest galaxies, but until now we have not had solid evidence for this observation. The Jets typical Active Galactic nuclei would have enough energy to power ten billion stars like our sun, our study shows for the first time from a purely observational view, the relationship between the mass of a galaxy and whether supernovae or AGN play a dominant role in quenching star formation, "says Kaviraj .
The scientific team from the University of Oxford, UK and the University of Hertfordshire, England studied a special class of post-Starburst galaxies, the lack of current star formation, but their spectra indicate that they formed a significant part of their stellar mass in the recent past. A recent period of vigorous star formation in these galaxies Therefore, it was quickly cleared so that these objects perfect test environments to probe the quenching. The galaxies studied in this work, by cosmological standards, nearby, at a distance of 1.5 billion light-years years or less.

With a novel combination of UV data from the Galaxy Evolution Explorer (an orbiting space telescope launched by NASA in 2003) and optical data from the Sloan Digital Sky Survey (one of the largest surveys on observations, with a special 2 ,5-Meter telescope equipped with a 120-megapixel camera;), the scientists were able to measure the efficiency of quenching takes place in the individual galaxies with unprecedented accuracy.

"The work is very topical," stresses Marc Sarzi, Research Fellow at the University of Hertfordshire and academic visitors in Oxford. "Post-Star burst galaxies are extremely rare objects, and it's only thanks to the large amount indicated in the Sloan survey, which we use, a considerable number of them."

Kaviraj adds: "In the AGN regime, the quenching efficiency is expected that positive scale galaxy with mass, while in the supernova regime the opposite trend is expected. We also know that AGN are clearly many more galaxies with masses of about 10 billion times the mass of the sun. Our results show that the expected dichotomy in the relationship between efficiency and quenching galaxy mass is in fact the data, just above the threshold expected mass - 10 billion times the mass of the sun! "

According to co-author Joe Silk is Savilian Professor of Astronomy at Oxford University and has pioneered the use of black holes in models of galaxy formation: "We have simply not understand the murky details of galaxy formation. Any form of 'feedback' slowing down and quenching both star formation in nearby galaxies and the distant universe. These results point to the perpetrators will probably be a combination of the effects of exploding stars and supermassive black holes, with black holes dominates the massive galaxies, as in contemporary Galaxy formation models.

Quantify the role that AGN in quenching star formation is of paramount importance that astrophysicists, as it would enable them to calibrate their models of galaxy formation. During the observations made in this study were in the vicinity of galaxies, the challenge now is to confirm these preliminary results and expand the scope of the work on a representative sample of galaxies: This category includes those who are much further away from the Peak epoch of star formation around 10 billion years ago, when the universe was only 25 percent of its current age!

The effort led by Kaviraj are under way, the observations of several large surveys, that traces the evolution of the universe in the last 10 billion years to the properties of the post-starburst galaxy population. The research work is expected to yield significant insights into the quenching and provide valuable restrictions on the current paradigm of galaxy formation.

Super Luminous Supernovae

Astronomers have announced today that they have found that the explosive transformation of a neutron star into a quark star (ie a Quark-Nova) has the right properties to explain the super-bright supernovae SN2006gy, SN2005gj and SN2005ap. Denis Leahy and Rachid Ouyed from the University of Calgary in Canada to present their findings today at the American Astronomical Society Meeting in St. Louis, Missouri. Their results are of particular interest for two reasons: so far, astronomers do not have a satisfactory explanation for super-bright supernovas, and this provides evidence for the existence of quark stars - a manifestation of a new state of matter.

The objects of study are the three brightest supernova ever observed. SN2006gy was in the galaxy NGC1260 at a distance from Earth of 240 million light-years years; SN2005gj and SN2005ap in more distant galaxies. They were observed at Lick Observatory for SN2006gy (Smith et al, 2008), at Mount Palomar for SN2005gj (Aldering et al 2006), and at McDonald Observatory for SN2005ap (Quimby et al 2008). It produces 100 times more energy than normal supernova light and are a challenge to explain.

We are studying the properties of quark stars, which have been proposed to exist, but has not yet been confirmed. The compact solid objects in the universe are known neutron stars: 16 kilometers and about 1.5 times as massive as our sun. Neutron stars are made of densely packed neutrons together and produced by the collapse of the core of a massive star at the end of his life, including a supernova explosion. Quark stars are even denser, the same Mass, but only 12 kilometers. Quark stars may be produced if the density of a neutron star is high enough. In this case, the neutrons dissolve into quarks, and also much release enough energy to power an explosion similar to the original that the explosion formed the neutron star.

Super-bright supernova may be the result of the second explosion (the Quark-Nova), which converts the neutron star into a quark star. The first explosion, the neutron star would not be noticed, known as the super-bright supernovae have occurred so far away from the Earth. The shock wave from the second explosion takes a few weeks to heat the gas expelled from the first explosion. As a result, the gas is very large (a hundred times the sun-Earth distance) if it is heated and produces a bright long-supernovae.

NASA Finds New Type Of Comet Dust Mineral

NASA researchers and scientists from the United States, Germany and Japan have found a new mineral in material that probably came from a comet.

The mineral, a manganese silicide Brownleeite named, was discovered within an interplanetary dust particles or IDP, which seems to have 26P/Grigg-Skjellerup from comets. The comet was originally discovered in 1902 and will return every 5 years. The team, the discovery is led by Keiko Nakamura-Messenger, a space scientist at NASA's Johnson Space Center in Houston.

"When I saw this mineral for the first time I immediately knew this was something nobody had seen before," said Nakamura-Messenger. "But it took several more months to consistent data, because this mineral grains were only 1 / 10000 of an inch in size."

A new method for the collection of internally displaced persons has been proposed by Scott Messenger, another Johnson Space scientists. He predicted 26P/Grigg-Skjellerup comet was a source of dust grains could be caught in the stratosphere of the earth at a certain time of the year.

In response to its forecast, NASA conducted stratosphere dust collections, with an ER-2 aircraft flown amount of NASA's Dryden Flight Research Center at Edwards Air Force Base in California. The aircraft collected internally displaced from this particular comet stream in April 2003. The new mineral was in one of the particles. To determine the mineral origin and to examine other materials dust, a powerful new transmission electron microscope was in 2005 in Johnson.

"Due to its extremely small size, we had to use state-of-the-art nano-analysis techniques under the microscope to measure the chemical composition and crystal structure of Keiko's new mineral," said Lindsay Keller, Johnson Space scientists and Co - discoverer of the new mineral. "This is a highly unusual material that was not predicted to either a component or cometary have by condensation in the solar nebula."

Since 1982, NASA routinely collected cosmic and interplanetary dust with high-altitude research aircraft. However, the sources of most dust particles were difficult to pin down because of their complex history in space. The Earth accretes over 40000 tonnes of dust particles from space every year, mostly originating in the disintegration of comets and asteroid collisions. This dust is a topic of interest, because it from the original building blocks of our solar system, planets, and our body.

The mineral was surrounded by several layers of other minerals were only in extraterrestrial rocks. There were 4324 minerals, which by the International Mineralogical Association, or IMA. This finding adds another mineral that list.

The IMA approved new mineral, Brownleeite, is named after Donald E. Brownlee, professor of astronomy at the University of Washington, Seattle. Brownlee founded the field of IP research. The understanding of the early solar system founded by IDP studies would not exist without his efforts. Brownlee is also the Principal Investigator of NASA's Stardust mission.