Archive for June 12, 2012

Galaxies NGC 4342, NGC 4291

June 12, 2012 Leave a comment

New results based studies of galaxies NGC 4342 and NGC 4291 are challenging the prevailing ideas as to how supermassive black holes grow in the centers of galaxies. New results based on the two objects shown here are challenging the prevailing ideas as to how supermassive black holes grow in the centers of galaxies. NGC 4342 and NGC 4291, the two galaxies in the study, are nearby in cosmic terms at distances of 75 million and 85 million light years respectively. In these composite images, X-rays from NASA’s Chandra X-ray Observatory are colored blue, while infrared data from the 2MASS project are seen in red.
Astronomers had known from previous observations that these galaxies host black holes with unusually large masses compared to the mass contained in the central bulge of stars. To study the dark matter envelopes contained in each galaxy, Chandra was used to examine their hot gas content, which was found to be widespread in both objects.
By analyzing the distribution of the hot gas, researchers were able to test whether the galaxies had “lost weight” through stars being pulled away during a tidal encounter with another galaxy. Estimates of the pressure of the hot gas, which must balance the gravitational pull of all the matter in the galaxy, showed that massive envelopes of dark matter must exist around each galaxy. Since this tidal stripping would have severely depleted the dark matter, which is more loosely tied to the galaxies than the stars, this process is unlikely to have occurred in either galaxy.

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Impact atlas catalogs over 635,000 Martian craters

June 12, 2012 Leave a comment

It’s  no secret that Mars is a beaten and battered planet — astronomers have been  peering for centuries at the violent impact craters created by cosmic buckshot  pounding its surface over billions of years. But just how beat up is it?

Really  beat up, according to researchers who recently finished counting, outlining and  cataloging a staggering 635,000 impact craters on Mars that are roughly a  kilometer or more in diameter.

As  the largest single database ever compiled of impacts on a planet or moon in our  solar system, the new information will be of help in dating the ages of  particular regions of Mars, said Stuart Robbins, a postdoctoral researcher at  the University of Colorado, Boulder (CU-Boulder), who led the effort.  The new crater atlas also should help  researchers better understand the history of water volcanism on Mars through  time, as well as the planet’s potential for past habitability by primitive  life, he said.

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NASA Mars Rover Team Aims For Landing Closer To Prime Science Site

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NASA has narrowed the target for its most advanced Mars rover, Curiosity, which will land on the Red Planet in August. The car-sized rover will arrive closer to its ultimate destination for science operations, but also closer to the foot of a mountain slope that poses a landing hazard.
“We’re trimming the distance we’ll have to drive after landing by almost half,” said Pete Theisinger, Mars Science Laboratory (MSL) project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, CA. “That could get us to the mountain months earlier.”
It was possible to adjust landing plans because of increased confidence in precision landing technology aboard the MSL spacecraft, which is carrying the rover. That spacecraft can aim closer without hitting Mount Sharp at the center of Gale crater. Rock layers located in the mountain are the prime location for research with the rover.

Curiosity is scheduled to land at approximately 10:31 p.m. PDT Aug. 5 (1:31 a.m. EDT, Aug. 6). Following checkout operations, Curiosity will begin a 2-year study of whether the landing vicinity ever offered an environment favorable for microbial life.

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ESO To Build World’s Biggest Eye On The Sky

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ESO is to build the largest optical/infrared telescope in the world. At its meeting in Garching today, the ESO Council approved the European Extremely Large Telescope (E-ELT) Programme, pending confirmation of four so-called ad referendum [1] votes. The E-ELT will start operations early in the next decade.

ESO’s governing body, the Council, met today, at the ESO Headquarters in Garching, Germany. The main topic on the agenda was the start of the European Extremely Large Telescope (E-ELT) Programme — the world’s biggest eye on the sky. The E-ELT will be a 39.3-metre segmented-mirror telescope sited on Cerro Armazones in northern Chile, close to ESO’s Paranal Observatory.

All of ESO’s Member States have already expressed very strong support for the E-ELT project (see eso1150). The Council has today voted in favour of a resolution for the approval of the E-ELT and its first suite of powerful instruments, pending confirmation of the so-called ad referendum votes.

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Black Hole Growth Found to Be Out of Sync

June 12, 2012 Leave a comment

New evidence from NASA’s Chandra X-ray Observatory challenges prevailing ideas about how black holes grow in the centers of galaxies. Astronomers long have thought that a supermassive black hole and the bulge of stars at the center of its host galaxy grow at the same rate — the bigger the bulge, the bigger the black hole. However, a new study of Chandra data has revealed two nearby galaxies with supermassive black holes that are growing faster than the galaxies themselves.
The mass of a giant black hole at the center of a galaxy typically is a tiny fraction — about 0.2 percent — of the mass contained in the bulge, or region of densely packed stars, surrounding it. The targets of the latest Chandra study, galaxies NGC 4342 and NGC 4291, have black holes 10 times to 35 times more massive than they should be compared to their bulges. The new observations with Chandra show the halos, or massive envelopes of dark matter in which these galaxies reside, also are overweight.
This study suggests the two supermassive black holes and their evolution are tied to their dark matter halos and did not grow in tandem with the galactic bulges. In this view, the black holes and dark matter halos are not overweight, but the total mass in the galaxies is too low.

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NASA’s Fermi Detects The Highest-Energy Light From A Solar Flare

During a powerful solar blast on March 7, NASA’s Fermi Gamma-ray Space Telescope detected the highest-energy light ever associated with an eruption on the sun. The discovery heralds Fermi’s new role as a solar observatory, a powerful new tool for understanding solar outbursts during the sun’s maximum period of activity.

A solar flare is an explosive blast of light and charged particles. The powerful March 7 flare, which earned a classification of X5.4 based on the peak intensity of its X-rays, is the strongest eruption so far observed by Fermi’s Large Area Telescope (LAT). The flare produced such an outpouring of gamma rays — a form of light with even greater energy than X-rays — that the sun briefly became the brightest object in the gamma-ray sky.

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NuSTAR To Drop From Plane And Rocket Into Space

NASA’s NuSTAR mission is scheduled to launch from Kwajalein Atoll in the central Pacific Ocean on June 13, no earlier than 8:30 a.m. PDT (11:30 a.m. EDT). The observatory, which will hunt for black holes and other exotic objects using specialized X-ray eyes, will be launched from a Pegasus XL rocket carried by an Orbital Science Corporation L-1011 “Stargazer” plane. The plane will take off from Kwajalein Atoll an hour before launch, flying out over the Pacific Ocean.

Why launch from the air? Plane-assisted launches are less expensive than those that take place from the ground. Less fuel is needed to boost cargo away from the pull of Earth’s gravity. NuSTAR is part of NASA’s Small Explorer program, which builds focused science missions at relatively low costs.

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220th AAS Meeting, 10-14 June 2012, Anchorage, Alaska

Exciting new findings about everything from our solar system to the most remote galaxies in the universe will be featured in six press conferences at the 220th meeting of the American Astronomical Society in downtown Anchorage, Alaska, 10-14 June 2012, at the Dena’ina and William A. Egan Civic & Convention Centers. Nearly 1,200 astronomers, educators, students, and journalists are registered to attend, making this one of the biggest summer meetings in AAS history.

Meeting with the Society are its Solar Physics Division (SPD) and the newly formed Laboratory Astrophysics Division (LAD). Regular AAS science sessions run Monday-Thursday, June 11-14.

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New Zealand’s Aoraki Mackenzie Named World’s Largest International Dark Sky Reserve

Over 1,600 square miles of New Zealand’s South Island have just been proclaimed as an International Dark Sky Reserve, making it the largest in the world. The Aoraki Mackenzie International Dark Sky Reserve (IDSR), comprised of the Aoraki/Mt. Cook National Park and the Mackenzie Basin, is the fourth such dark sky reserve in the world.

International Dark-Sky Association’s Executive Director Bob Parks remarks, “The new reserve is coming in at a ‘Gold’ level status. That means the skies there are almost totally free from light pollution. To put it simply, it is one of the best stargazing sites on Earth.”

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WISE Finds Few Brown Dwarfs Close To Home

Astronomers are getting to know the neighbors better. Our sun resides within a spiral arm of our Milky Way galaxy about two-thirds of the way out from the center. It lives in a fairly calm, suburb-like area with an average number of stellar residents. Recently, NASA’s Wide-field Infrared Survey Explorer, or WISE, has been turning up a new crowd of stars close to home: the coldest of the brown dwarf family of “failed” stars.

Now, just as scientists are “meeting and greeting” the new neighbors, WISE has a surprise in store: there are far fewer brown dwarfs around us than predicted.

“This is a really illuminating result,” said Davy Kirkpatrick of the WISE science team at NASA’s Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. “Now that we’re finally seeing the solar neighborhood with keener, infrared vision, the little guys aren’t as prevalent as we once thought.”

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