Archive for March, 2013

Gravitational Lensing In The Peculiar “Magatama” Galaxy

Credit: Ehime University

Credit: Ehime University

In a course of studying young galaxies at a distance of 11.6 billion light years from Earth, a team of astronomers led by Professor Yoshiaki Taniguchi (Ehime University) noticed a strangely shaped galaxy that looks like a “magatama”, an ancient, comma-shaped Japanese amulet made of stone (Figure 1). Subsequent research revealed that the magatama galaxy was actually an overlapping system of two young galaxies lying in an extremely close line of sight–an exceedingly rare occurrence among celestial objects. The small angular separation between the foreground and background galaxies gave the current team an opportunity to investigate the effect of gravitational lensing on the properties of the background galaxy. A member of the team, university student Yuya Nakahiro (Ehime University), calculated that the effect of gravitational amplification would be 20% at most. The foreground young galaxy is still forming, and the team concluded that the gravitational lensing effect from such a young galaxy does not affect the luminosity of its background galaxy.

Dr. Inoue expressed his surprise at the finding: “This result was very amazing to me, since this is the discovery of an extremely rare system.” The finding sparked Professor Taniguchi’s idea for the current research: “Soon after I knew this observational result, I became aware of the possibility that light from LAE 221724+001716 is gravitationally amplified by the foreground galaxy”.

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Spotlight Live: Starbursts In The Early Universe

THE MILKY WAY TODAY may fire up one new star every year, but billions of years ago, a subset of galaxies in the relatively young universe were producing new stars at a rate of 1,000 per year. Now, a multi-national team of astronomers has found that these distant, dusty galaxies were churning out stars much earlier than once believed – as early as one billion years after the Big Bang, nearly 13 billion years ago.

On Friday March 29, 12:00-12:30pm PDT, science writer Bruce Lieberman will ask your questions about the starbursts and the early universe with members of the research team: John E. Carlstrom, Dan P. Marrone and Joaquin D. Vieira.

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Saturn Is Like An Antiques Shop, Cassini Suggests

A new analysis of data from NASA’s Cassini spacecraft suggests that Saturn’s moons and rings are gently worn vintage goods from around the time of our solar system’s birth.

Though they are tinted on the surface from recent “pollution,” these bodies date back more than 4 billion years. They are from around the time that the planetary bodies in our neighborhood began to form out of the protoplanetary nebula, the cloud of material still orbiting the sun after its ignition as a star. The paper, led by Gianrico Filacchione, a Cassini participating scientist at Italy’s National Institute for Astrophysics, Rome, has just been published online by the Astrophysical Journal.

“Studying the Saturnian system helps us understand the chemical and physical evolution of our entire solar system,” said Filacchione. “We know now that understanding this evolution requires not just studying a single moon or ring, but piecing together the relationships intertwining these bodies.”

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Hunting High-Mass Stars With Herschel

Copyright: ESA/PACS & SPIRE consortia, A. Rivera-Ingraham & P.G. Martin, Univ. Toronto, HOBYS Key Programme (F. Motte)

Copyright: ESA/PACS & SPIRE consortia, A. Rivera-Ingraham & P.G. Martin, Univ. Toronto, HOBYS Key Programme (F. Motte)

In this new view of a vast star-forming cloud called W3, ESA’s Herschel space observatory tells the story of how massive stars are born.

Spanning almost 200 light-years, W3 is one of the largest star-formation complexes in the outer Milky Way, hosting the formation of both low- and high-mass stars. The distinction is drawn at eight times the mass of our own Sun: above this limit, stars end their lives as supernovas.

Dense, bright blue knots of hot dust marking massive star formation dominate the upper left of the image in the two youngest regions in the scene: W3 Main and W3 (OH). Intense radiation streaming away from the stellar infants heats up the surrounding dust and gas, making it shine brightly in Herschel’s infrared-sensitive eyes.

By studying the two regions of massive star formation – W3 Main and W3 (OH) – scientists have made progress in solving one of the major conundrums in the birth of massive stars. That is, even during their formation, the radiation blasting away from these stars is so powerful that they should push away the very material they are feeding from. If this is the case, how can massive stars form at all?

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New Radio Telescope In SA Will Also Shed New Light On The Earliest Moments Of The Universe: C-BASS South Commissioning At Hartebeesthoek

In the week that saw the release of the first results from the European Space Agency’s Planck satellite, astronomers at the Hartebeesthoek Radio Astronomy Observatory (HartRAO) near Johannesburg are working on a new radio telescope that will also shed new light on the very earliest moments of the universe.

The C-Band All-Sky Survey (C-BASS) is a project to map the sky in microwave (short-wavelength radio) radiation. Like Planck, it will survey the whole sky, mapping out how bright the sky is, and also the orientation of the waves (called polarization). While Planck observes very short wavelengths, C-BASS observes longer wavelengths that are actually easier to observe from the ground.

“Because we want to observe at these longer wavelengths, the C-BASS telescope has to be much bigger than the telescope on Planck,” explains South African C-BASS team member Charles Copley. “The C-BASS dish is over seven metres across – much too big to launch on a rocket.”

In order to observe the entire sky, C-BASS needs to use two different telescopes, one in the northern hemisphere and one in the southern hemisphere.

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Sun Block For The Big Dog: Detection Of Titanium Oxide And Titanium Dioxide Around The Giant Star VY Canis Majoris

Credits: Molecule symbols: CDMS/T. Kamiński, Background image: NASA/ESA and R. Humphreys (University of Minnesota)

Credits: Molecule symbols: CDMS/T. Kamiński, Background image: NASA/ESA and R. Humphreys (University of Minnesota)

An international team of astronomers, including researchers from the Max Planck Institute for Radio Astronomy and from the University of Cologne, discovered two titanium oxides, TiO and TiO2, at radio wavelengths using telescope arrays in the USA and in France. The detection was made in the environment of VY Canis Majoris, a giant star close to the end of its life.

The discovery was made in the course of a study of a spectacular star, VY Canis Majoris or VY CMa for short, which is a variable star located in the constellation Canis Major (Greater Dog). “VY CMa is not an ordinary star, it is one of the largest stars known, and it is close the end of its life,” says Tomasz Kamiński from the Max Planck Institute for Radio Astronomy (MPIfR). In fact, with a size of about one to two thousand times that of the Sun, it could extend out to the orbit of Saturn if it were placed in the center of our Solar System.

The star ejects large quantities of material which forms a dusty nebula. The complexity of this nebula has been puzzling astronomers for decades. It has been formed as a result of stellar wind, but it is not understood well why it is so far from having a spherical shape. Neither is known what physical process blows the wind, i.e. what lifts the material up from the stellar surface and makes it expand. “The fate of VY CMa is to explode as a supernova, but it is not known exactly when it will happen”, adds Karl Menten, head of the “Millimeter and Submillimeter Astronomy” Department at MPIfR.

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Hubble Observes The Hidden Depths Of Messier 77

Image credit: NASA, ESA & A. van der Hoeven

Image credit: NASA, ESA & A. van der Hoeven

Messier 77 is a galaxy in the constellation of Cetus, some 45 million light-years away from us. Also known as NGC 1068, it is one of the most famous and well-studied galaxies. It is a real star among galaxies, with more papers written about it than many other galaxies put together!

Despite its current fame and striking swirling appearance, the galaxy has been a victim of mistaken identity a couple of times; when it was initially discovered in 1780, the distinction between gas clouds and galaxies was not known, causing finder Pierre Méchain to miss its true nature and label it as a nebula. It was misclassified again when it was subsequently listed in the Messier Catalogue as a star cluster.

Now, however, it is firmly categorised as a barred spiral galaxy, with loosely wound arms and a relatively small central bulge. It is the closest and brightest example of a particular class of galaxies known as Seyfert galaxies — galaxies that are full of hot, highly ionised gas that glows brightly, emitting intense radiation.

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