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Archive for February, 2014

New Fast And Furious Black Hole Found

February 28, 2014 Leave a comment

Image Credits: M83 - NASA, ESA and the Hubble Heritage Team (WFC3/UVIS, STScI-PRC14-04a).MQ1

Image Credits: M83 – NASA, ESA and the Hubble Heritage Team (WFC3/UVIS, STScI-PRC14-04a).MQ1

A team of Australian and American astronomers have been studying nearby galaxy M83 and have found a new superpowered small black hole, named MQ1, the first object of its kind to be studied in this much detail.

Astronomers have found a few compact objects that are as powerful as MQ1, but have not been able to work out the size of the black hole contained within them until now.

The team observed the MQ1 system with multiple telescopes and discovered that it is a standard-sized small black hole, rather than a slightly bigger version that was theorised to account for all its power.

Curtin University senior research fellow Dr Roberto Soria, who is part of the International Centre for Radio Astronomy Research (ICRAR) and led the team investigating MQ1, said it was important to understand how stars were formed, how they evolved and how they died, within a spiral shaped galaxy like M83.

“MQ1 is classed as a microquasar – a black hole surrounded by a bubble of hot gas, which is heated by two jets just outside the black hole, powerfully shooting out energy in opposite directions, acting like cosmic sandblasters pushing out on the surrounding gas,” Dr Soria said.

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Gamma-Rays Tighten Window On Dark Matter Theories

February 28, 2014 Leave a comment

Observed data fitting the dark matter component, after subtracting all other components toward the Galactic Center.

Observed data fitting the dark matter component, after subtracting all other components toward the Galactic Center.

UC Irvine astrophysicists report that gamma-ray photons observed from the center of the Milky Way Galaxy are consistent with the intriguing possibility of dark matter annihilation, according to research submitted to the journal Physical Review D.

Kevork Abazajian, Nicolas Canac, Shunsaku Horiuchi and Manoj Kaplinghat analyzed data from NASA’s space-borne Fermi Gamma-ray Space Telescope and found that only a narrow range of dark matter models can produce an excess of gamma rays coming from the Milky Way. These gamma rays could be produced as particles of dark matter annihilate one another.

“The data provides a better-than 10 percent precise determination of the dark matter’s particle mass with the best estimates we have of what else is going on in the Galactic Center,” says Abazajian.

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Closest, Brightest Supernova In Decades Is Also A Little Weird

February 28, 2014 Leave a comment

Image by W. Zheng and A. Filippenko, UC Berkeley

Image by W. Zheng and A. Filippenko, UC Berkeley

A bright supernova discovered only six weeks ago in a nearby galaxy is provoking new questions about the exploding stars that scientists use as their main yardstick for measuring the universe.

Called SN 2014J, the glowing supernova was discovered by a professor and his students in the United Kingdom on Jan. 21, about a week after the stellar explosion first became visible as a pinprick of light in its galaxy, M82, 11.4 million light years away in the Big Dipper. Still visible today through small telescopes, it is the brightest supernova seen from Earth since SN1987A, 27 years ago, and may be the closest Type Ia supernova – the kind used to measure cosmic distances – in more than 77 years.

When University of California, Berkeley, astronomer Alex Filippenko’s research team looked for the supernova in data collected by the Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory near San Jose, Calif., they discovered that the robotic telescope had actually taken a photo of it 37 hours after it appeared, unnoticed, on Jan. 14.

Combining this observation with another chance observation by a Japanese amateur astronomer, Filippenko’s team was able to calculate that SN 2014J had unusual characteristics — it brightened faster than expected for a Type Ia supernova and, even more intriguing, it exhibited the same unexpected, rapid brightening as another supernova that KAIT discovered and imaged last year – SN 2013dy.

“Now, two of the three most recent and best-observed Type Ia supernovae are weird, giving us new clues to how stars explode,” said Filippenko.

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Astronomers Spot Record-Breaking Lunar Impact

February 26, 2014 Leave a comment

A meteorite with the mass of a small car crashed into the Moon last September, according to Spanish astronomers. The impact, the biggest seen to date, produced a bright flash and would have been easy to spot from the Earth. The scientists publish their description of the event in the journal Monthly Notices of the Royal Astronomical Society.

The Moon lacks the atmosphere that prevents small rocks from space from reaching the surface of the Earth. The result is very visible – vast numbers of craters large and small cover the whole of our nearest neighbour and record 4.5 billion years of collisions that span the history of the Solar system.

Although there is almost no chance of a very large object striking the Moon or planets, collisions with smaller objects are very common even today. The odds of seeing one of these by chance are pretty poor, so scientists have set up networks of telescopes that can detect them automatically.

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Detection Of Water Vapor In The Atmosphere Of A Hot Jupiter

February 26, 2014 Leave a comment

Although liquid water covers a majority of Earth’s surface, scientists are still searching for planets outside of our solar system that contain water. Researchers at Caltech and several other institutions have used a new technique to analyze the gaseous atmospheres of such extrasolar planets and have made the first detection of water in the atmosphere of the Jupiter-mass planet orbiting the nearby star tau Boötis. With further development and more sensitive instruments, this technique could help researchers learn about how many planets with water—like Earth—exist within our galaxy.

Scientists have previously detected water vapor on a handful of other planets, but these detections could only take place under very specific circumstances, says graduate student Alexandra Lockwood, the first author of the study. “When a planet transits—or passes in orbit in front of—its host star, we can use information from this event to detect water vapor and other atmospheric compounds,” she says. “Alternatively, if the planet is sufficiently far away from its host star, we can also learn about a planet’s atmosphere by imaging it.”

However, significant portions of the population of extrasolar planets do not fit either of these criteria, and there was not really a way to find information about the atmospheres of these planets. Looking to resolve this problem, Lockwood and her adviser Geoffrey Blake, professor of cosmochemistry and planetary sciences and professor of chemistry, applied a novel technique for finding water in a planetary atmosphere. Other researchers had used similar approaches previously to detect carbon monoxide in tau Boötis b.

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Bullying Black Holes Force Galaxies To Stay Red And Dead

February 26, 2014 Leave a comment

Copyright: Digitised Sky Survey/NASA Chandra/Southern Observatory for Astrophysical Research/Very Large Array (Robert Dunn et al. 2010)

Copyright: Digitised Sky Survey/NASA Chandra/Southern Observatory for Astrophysical Research/Very Large Array (Robert Dunn et al. 2010)

Giant elliptical galaxies are the most puzzling type of galaxy in the Universe. Since they mysteriously shut down their star-forming activity and remain home only to the longest-lived of their stars – which are low-mass ones and appear red – astronomers often call these galaxies ‘red and dead’.

Up until now, it was thought that red-and-dead galaxies were poor in cold gas – the vital raw material from which stars are born. While cold gas is abundant in spiral galaxies with lively star formation, the lack of it in giant ellipticals seemed to explain the absence of new stars.

Astronomers have long been debating the physical processes leading to the end of their star formation. They speculated that these galaxies somehow expelled the cold gas, or that they had simply used it all to form stars in the past. Although the reason was uncertain, one thing seemed to have been established: these galaxies are red and dead because they no longer possess the means to sustain the production of stars.

This view is being challenged by a new study based on data from ESA’s Herschel Space Observatory. The results are published in Monthly Notices of the Royal Astronomical Society.

“We looked at eight giant elliptical galaxies that nobody had looked at with Herschel before and we were delighted to find that, contrary to previous belief, six out of eight abound with cold gas”, explains Norbert Werner from Stanford University in California, USA, who led the study.
This is the first time that astronomers have seen large amounts of cold gas in red-and-dead galaxies that are not located at the centre of a massive galaxy cluster.

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With A Deadly Embrace, ‘Spidery’ Pulsars Consume Their Mates

February 24, 2014 Leave a comment

Artist's concept. Image Credit: NASA's Goddard Space Flight Center

Artist’s concept. Image Credit: NASA’s Goddard Space Flight Center

Black widow spiders and their Australian cousins, known as redbacks, are notorious for their tainted love, expressed as an unsettling tendency to kill and devour their male partners. Astronomers have noted similar behavior among two rare breeds of binary system that contain rapidly spinning neutron stars, also known as pulsars.

“The essential features of black widow and redback binaries are that they place a normal but very low-mass star in close proximity to a millisecond pulsar, which has disastrous consequences for the star,” said Roger Romani, a member of the Kavli Institute for Particle Astrophysics and Cosmology, an institute run jointly by Stanford and SLAC National Accelerator Laboratory in Menlo Park, Calif. Black widow systems contain stars that are both physically smaller and of much lower mass than those found in redbacks.

So far, astronomers have found at least 18 black widows and nine redbacks within the Milky Way, and additional members of each class have been discovered within the dense globular star clusters that orbit our galaxy.

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