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Posts Tagged ‘astrophysics’

Rings And Loops In The Stars: Planck’s Stunning New Images


Credit: M. Peel / JCBA / Planck / ESA

Credit: M. Peel / JCBA / Planck / ESA

A ring of dust 200 light years across and a loop covering a third of the sky: two of the results in a new map from the Planck satellite. Dr Mike Peel and Dr Paddy Leahy of the Jodrell Bank Centre for Astrophysics (JCBA) presented the images today at the National Astronomy Meeting (NAM 2015) at Venue Cymru, Llandudno, Wales.

The European Space Agency (ESA) Planck satellite, launched in 2009 to study the ancient light of the Big Bang, has also given us maps of our own Galaxy, the Milky Way, in microwaves (radiation at cm- to mm-wavelengths). Microwaves are generated by electrons spiralling in the Galaxy’s magnetic field at nearly the speed of light (the synchrotron process); by collisions in interstellar plasma, by thermal vibration of interstellar dust grains, and by “anomalous” microwave emission (AME), which may be from spinning dust grains.

The relative strength of these processes changes with wavelength, and are separated using multi-wavelength measurements from Planck, from NASA’s WMAP satellite, and from ground-based radio telescopes, giving maps of each component.

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Exiled Stars Explode Far From Home


Artist's concept. Image by Dr. Alex H Parker, NASA and the SDSS

Artist’s concept. Image by Dr. Alex H Parker, NASA and the SDSS

Sharp images obtained by the Hubble Space Telescope confirm that three supernovae discovered several years ago exploded in the dark emptiness of intergalactic space, having been flung from their home galaxies millions or billions of years earlier.

Most supernovae are found inside galaxies containing hundreds of billions of stars, one of which might explode per century per galaxy.

These lonely supernovae, however, were found between galaxies in three large clusters of several thousand galaxies each. The stars’ nearest neighbors were probably 300 light years away, nearly 100 times farther than our sun’s nearest stellar neighbor, Proxima Centauri, 4.24 light years distant.

uch rare solitary supernovae provide an important clue to what exists in the vast empty spaces between galaxies, and can help astronomers understand how galaxy clusters formed and evolved throughout the history of the universe.

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Hubble Video Shows Shock Collision Inside Black Hole Jet


Credit: NASA, ESA, and E. Meyer (STScI)

Credit: NASA, ESA, and E. Meyer (STScI)

When you’re blasting though space at more than 98 percent of the speed of light, you may need driver’s insurance. Astronomers have discovered for the first time a rear-end collision between two high-speed knots of ejected matter from a super-massive black hole. This discovery was made while piecing together a time-lapse movie of a plasma jet blasted from a supermassive black hole inside a galaxy located 260 million light-years from Earth.

he finding offers new insights into the behavior of “light-saber-like” jets that are so energized that they appear to zoom out of black holes at speeds several times the speed of light. This “superluminal” motion is an optical illusion due to the very fast real speed of the plasma, which is close to the universal maximum of the speed of light.

Such extragalactic jets are not well understood. They appear to transport energetic plasma in a confined beam from the central black hole of the host galaxy. The new analysis suggests that shocks produced by collisions within the jet further accelerate particles and brighten the regions of colliding material.

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NASA Instrument On Rosetta Makes Comet Atmosphere Discovery


Image credit: ESA/Rosetta/NAVCAM

Image credit: ESA/Rosetta/NAVCAM

Data collected by NASA’s Alice instrument aboard the European Space Agency’s Rosetta spacecraft reveal that electrons close to the surface of comet 67P/Churyumov-Gerasimenko — not photons from the sun, as had been believed — cause the rapid breakup of water and carbon dioxide molecules spewing from the comet’s surface.

“The discovery we’re reporting is quite unexpected,” said Alan Stern, principal investigator for the Alice instrument at the Southwest Research Institute (SwRI) in Boulder, Colorado. “It shows us the value of going to comets to observe them up close, since this discovery simply could not have been made from Earth or Earth orbit with any existing or planned observatory. And, it is fundamentally transforming our knowledge of comets.

A report of the findings has been accepted for publication by the journal Astronomy and Astrophysics.

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Hubble Observes One-of-a-Kind Star Nicknamed ‘Nasty’


Artist's Illustration Credit: NASA, ESA, and G. Bacon (STScI)

Artist’s Illustration Credit: NASA, ESA, and G. Bacon (STScI)

Astronomers using NASA’s Hubble Space Telescope have uncovered surprising new clues about a hefty, rapidly aging star whose behavior has never been seen before in our Milky Way galaxy. In fact, the star is so weird that astronomers have nicknamed it “Nasty 1,” a play on its catalog name of NaSt1. The star may represent a brief transitory stage in the evolution of extremely massive stars.

First discovered several decades ago, Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving star that is much more massive than our sun. The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core.

But Nasty 1 doesn’t look like a typical Wolf-Rayet star. The astronomers using Hubble had expected to see twin lobes of gas flowing from opposite sides of the star, perhaps similar to those emanating from the massive star Eta Carinae, which is a Wolf-Rayet candidate. Instead, Hubble revealed a pancake-shaped disk of gas encircling the star. The vast disk is nearly 2 trillion miles wide, and may have formed from an unseen companion star that snacked on the outer envelope of the newly formed Wolf-Rayet. Based on current estimates, the nebula surrounding the stars is just a few thousand years old, and as close as 3,000 light-years from Earth.

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NASA’s WISE Spacecraft Discovers Most Luminous Galaxy In Universe

May 21, 2015 1 comment

Artist's concept. Image credit: N/A

Artist’s concept. Image credit: N/A

A remote galaxy shining with the light of more than 300 trillion suns has been discovered using data from NASA’s Wide-field Infrared Survey Explorer (WISE). The galaxy is the most luminous galaxy found to date and belongs to a new class of objects recently discovered by WISE — extremely luminous infrared galaxies, or ELIRGs.

“We are looking at a very intense phase of galaxy evolution,” said Chao-Wei Tsai of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, lead author of a new report appearing in the May 22 issue of The Astrophysical Journal. “This dazzling light may be from the main growth spurt of the galaxy’s black hole.

The brilliant galaxy, known as WISE J224607.57-052635.0, may have a behemoth black hole at its belly, gorging itself on gas. Supermassive black holes draw gas and matter into a disk around them, heating the disk to roaring temperatures of millions of degrees and blasting out high-energy, visible, ultraviolet, and X-ray light. The light is blocked by surrounding cocoons of dust. As the dust heats up, it radiates infrared light.

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Giant Spiraling Molecular Gas Arms As Cradles Of Dense Massive Molecular Cores


Credit: ALMA(ESO/NAOJ/NRAO), H. B. Liu, J. Dale

Credit: ALMA(ESO/NAOJ/NRAO), H. B. Liu, J. Dale

A research team led by Dr. Hauyu Liu at the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA) observed the luminous OB cluster-forming massive molecular clump G33.92+0.11 with the Atacama Large Millimeter/submillimeter Array (ALMA), and unveiled the fine molecular gas structures deeply embedded at the center of the parent molecular cloud. This finding provides a greatly simplified picture of overall cloud geometry and kinematics, which represents a crucial step forward in the understanding of the upper end of the stellar and molecular core mass functions. The research was published in the April 28 issue of The Astrophysical Journal.

Via ALMA observations, this research for the first time resolved an embedded giant coherent dense gas structure on a several light-year scale. Surprisingly, this dense gas structure presents several spiral arms, which appear like a version of the previously observed spiral arms surrounding the low-mass protobinary, scaled-up by a factor of ~103. These giant spiral arms, and the massive molecular gas cores located at their convergence, are cradles to form the highest mass stars in this stellar cluster.

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