Archive

Archive for April 22, 2013

ALMA Pinpoints Early Galaxies At Record Speed


A team of astronomers has used the new ALMA (Atacama Large Millimeter/submillimeter Array) telescope to pinpoint the locations of over 100 of the most fertile star-forming galaxies in the early Universe. ALMA is so powerful that, in just a few hours, it captured as many observations of these galaxies as have been made by all similar telescopes worldwide over a span of more than a decade.

The most fertile bursts of star birth in the early Universe took place in distant galaxies containing lots of cosmic dust. These galaxies are of key importance to our understanding of galaxy formation and evolution over the history of the Universe, but the dust obscures them and makes them difficult to identify with visible-light telescopes. To pick them out, astronomers must use telescopes that observe light at longer wavelengths, around one millimetre, such as ALMA.

“Astronomers have waited for data like this for over a decade. ALMA is so powerful that it has revolutionised the way that we can observe these galaxies, even though the telescope was not fully completed at the time of the observations,” said Jacqueline Hodge (Max-Planck-Institut für Astronomie, Germany), lead author of the paper presenting the ALMA observations.

Full Story: http://www.eso.org/public/news/eso1318/

Strange New Bursts Of Gamma-Rays Point To A New Way To Destroy A Star


A team led by the University of Warwick has pinpointed a new type of exceptionally powerful and long-lived cosmic explosion, prompting a theory that they arise in the violent death throes of a supergiant star. These explosions create powerful blasts of high energy gamma-rays, known as gamma-ray bursts, but while most bursts are over in about a minute, this new type can last for several hours.

The first example was found by astronomers on Christmas Day 2010, but it lacked a measurement of distance and so remained shrouded in mystery with two competing theories put forward for its origin. The first model suggested it was down to an asteroid, shredded by the gravity of a dense neutron star in our own galaxy, the second that it was a supernova in a galaxy 3.5 billion light years away, or in the more common language of astronomers at a redshift of 0.33.

A new study by a team of scientists led by Dr Andrew Levan at the University of Warwick finds several more examples of these unusual cosmic explosions and shows that the Christmas Day burst took place in a galaxy much further away than the two theories suggested.

Full Story:  http://www2.warwick.ac.uk/newsandevents/grb

Where Are The Best Windows Into Europa’s Interior?


The surface of Jupiter’s moon Europa exposes material churned up from inside the moon and also material resulting from matter and energy coming from above. If you want to learn about the deep saltwater ocean beneath this unusual world’s icy shell — as many people do who are interested in possible extraterrestrial life — you might target your investigation of the surface somewhere that has more of the up-from-below stuff and less of the down-from-above stuff.

New analysis of observations made more than a decade ago by NASA’s Galileo mission to Jupiter helps identify those places.

“We have found the regions where charged electrons and ions striking the surface would have done the most, and the least, chemical processing of materials emplaced at the surface from the interior ocean,” said J. Brad Dalton of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., lead author of the report published recently in the journal Planetary and Space Science. “That tells us where to look for materials representing the most pristine ocean composition, which would be the best places to target with a lander or study with an orbiter.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-134

Supernova Remnant SN 1006


Credits: NASA / CXC/Middlebury College / F.Winklerch

Credits: NASA / CXC/Middlebury College / F.Winklerch

This year, astronomers around the world have been celebrating the 50th anniversary of X-ray astronomy. Few objects better illustrate the progress of the field in the past half-century than the supernova remnant known as SN 1006.

When the object we now call SN 1006 first appeared on May 1, 1006 A.D., it was far brighter than Venus and visible during the daytime for weeks. Astronomers in China, Japan, Europe, and the Arab world all documented this spectacular sight. With the advent of the Space Age in the 1960s, scientists were able to launch instruments and detectors above Earth’s atmosphere to observe the universe in wavelengths that are blocked from the ground, including X-rays. SN 1006 was one of the faintest X-ray sources detected by the first generation of X-ray satellites.

The new Chandra image provides new insight into the nature of SN 1006, which is the remnant of a so-called Type Ia supernova. This class of supernova is caused when a white dwarf pulls too much mass from a companion star and explodes, or when two white dwarfs merge and explode. Understanding Type Ia supernovas is especially important because astronomers use observations of these explosions in distant galaxies as mileposts to mark the expansion of the universe.

Full Story: http://www.nasa.gov/mission_pages/chandra/multimedia/tapestry.html