Archive

Archive for July, 2013

Capturing Black Hole Spin Could Further Understanding Of Galaxy Growth


Artist’s impression. Image credit: NASA/JPL-Caltech

Artist’s impression. Image credit: NASA/JPL-Caltech

Astronomers have found a new way of measuring the spin in supermassive black holes, which could lead to better understanding about how they drive the growth of galaxies.

The scientists at Durham University, observed a black hole – with mass 10 million times that of our Sun – at the centre of a spiral galaxy 500 million light years from Earth while it was feeding on the surrounding disc of material that fuels its growth and powers its activity.

By viewing optical, ultra-violet and soft x-rays generated by heat as the black hole fed, they were able to measure how far the disc was from the black hole.

This distance depends on black hole spin as a fast spinning black hole pulls the disc in closer to itself, the researchers said. Using the distance between the black hole and the disc, the scientists were able to estimate the spin of the black hole.

The scientists said that understanding spin could lead to greater understanding of galaxy growth over billions of years.

Full Story: https://www.dur.ac.uk/news/allnews/?itemno=18365
Also: http://www.ras.org.uk/news-and-press/224-news-2013/2320-capturing-black-hole-spin-could-further-understanding-of-galaxy-growth

This Is Your Galaxy: New Data Help Astronomers Explore The Hidden Milky Way


Today, astronomers with the Sloan Digital Sky Survey III (SDSS-III) released a new online public data set featuring 60,000 stars that are helping to tell the story of how our Milky Way galaxy formed.

The highlight of today’s “Data Release 10” is a new set of high-resolution stellar spectra — measurements of the amount of light given off by a star at each wavelength — using infrared light, invisible to human eyes but able to penetrate the veil of dust that obscures the center of the Galaxy.

“This is the most comprehensive collection of infrared stellar spectra ever made,” said Steven Majewski of the University of Virginia, the lead scientist for the APOGEE project. “Sixty thousand stars is almost ten times more high-resolution infrared stellar spectra than have ever been measured before, by all the world’s telescopes. Selected from all the different parts of our galaxy, from the nearly-empty outskirts to the dust-enshrouded center, these spectra are allowing us to peel back the curtain on the hidden Milky Way.”

Full Story and Data Link: http://www.sdss3.org/press/dr10.php

NASA’s Chandra Sees Eclipsing Planet In X-rays For First Time


For the first time since exoplanets, or planets around stars other than the sun, were discovered almost 20 years ago, X-ray observations have detected an exoplanet passing in front of its parent star.

An advantageous alignment of a planet and its parent star in the system HD 189733, which is 63 light-years from Earth, enabled NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM Newton Observatory to observe a dip in X-ray intensity as the planet transited the star.

“Thousands of planet candidates have been seen to transit in only optical light,” said Katja Poppenhaeger of Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., who led a new study to be published in the Aug. 10 edition of The Astrophysical Journal. “Finally being able to study one in X-rays is important because it reveals new information about the properties of an exoplanet.”

Full Story: http://www.nasa.gov/mission_pages/chandra/news/exoplanet-HD189733b.html

Comet Of The Century? Not Yet!


On September 2nd, 2012, two Russian astronomers discovered a comet designated as C/2012 S1 ISON. When the orbit was calculated, astronomers realized that the object would pass at only 1.3 solar radii from the Sun on November 28th, 2013. Numerous press articles contended that the object would be as bright as the full Moon and that in fact it could become “the comet of the century”.

Dr. Ignacio Ferrin, Astronomer from the Institute of Physics of the University of Antioquia, in Medellín, Colombia, has concluded a study of the comet, using the latest observations available. Dr. Ferrin is a researcher and Faculty Member in the Astronomy Program of that Institute. He is a recognized cometary specialist.

“Comet ISON has presented a peculiar behavior”, said Dr. Ferrín. “The light curve has exhibited a “slowdown event” characterized by a constant brightness with no indication of a brightness increase tendency. This slowdown took place around January 13th, 2013. For 132 days after that date and up to the last available observation, the brightness has remained constant”. Thus the astronomer concludes that it is highly unlikely that the comet will be as bright as the full Moon.

Full Story: http://urania.udea.edu.co/sitios/facom/press.php?_inicomp=3&_numcomp=1&#

The Largest Magnetic Fields In The Universe


An ultra-dense (“hypermassive”) neutron star is formed when two neutron stars in a binary system finally merge. Its short life ends with the catastrophic collapse to a black hole, possibly powering a short gamma-ray burst, one of the brightest explosions observed in the universe. Short gamma-ray bursts as observed with satellites like XMM Newton, Fermi or Swift release within a second the same amount of energy as our Galaxy in one year. It has been speculated for a long time that enormous magnetic field strengths, possibly higher than what has been observed in any known astrophysical system, are a key ingredient in explaining such emission. Scientists at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) have now succeeded in simulating a mechanism which could produce such strong magnetic fields (stronger than ten or hundred million billion times the Earth’s magnetic field)* prior to the collapse to a black hole.

* Strength inserted from elsewhere in the story.

Full Story: http://www.aei.mpg.de/303590/Die_staerksten_Magnetfelder_im_Universum

A New Baby Picture Of The Universe


THIS SPRING, HUMANITY WAS SHOWN ITS MOST DETAILED MAP of the early universe ever created. Generated by observations from the Planck spacecraft, the map shows fluctuations in temperature in the relic radiation left over from the Big Bang – the moment when space and time came into existence nearly 14 billion years ago. That relic radiation, a kind of afterglow from the Big Bang, is called the cosmic microwave background, or CMB. It streams toward Earth from everywhere in the sky, and it provides a snapshot of what the universe looked like when the CMB was generated 380,000 years after the Big Bang.

Recently, scientists on the Planck team found certain large-scale features on the CMB sky, which they called “anomalies,” that they cannot explain. One of them, for example, is a large cold spot, which corresponds to an anomalously large area of high density. What this means: the theory for how the universe began may need to be modified, amended or even fundamentally changed. In any of these cases, the result will be consequential to how we understand the evolution of existence.

Full Story: http://www.kavlifoundation.org/science-spotlights/kicc-planck-universe

Galaxies, Comets, And Stars! Oh My!


Comet ISON. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Comet ISON. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

The sun-approaching Comet ISON floats against a seemingly infinite backdrop of numerous galaxies and a handful of foreground stars. The icy visitor, with its long gossamer tail, appears to be swimming like a tadpole through a deep pond of celestial wonders.

In reality, the comet is much, much closer. The nearest star to the Sun is over 60,000 times farther away, and the nearest large galaxy to the Milky Way is over thirty billion times more distant. These vast dimensions are lost in this deep space Hubble exposure that visually combines our view of the universe from the very nearby to the extraordinarily far away.

Full Story and Images: http://hubblesite.org/newscenter/archive/releases/2013/31/image/a/

NASA Mission Discovers Particle Accelerator In Heart Of Van Allen Radiation Belts


Using data from a NASA satellite, scientists have discovered a massive particle accelerator in the heart of one of the harshest regions of near-Earth space, a region of super-energetic, charged particles surrounding the globe and known as the Van Allen radiation belts.

New results from NASA’s Van Allen Probes show the acceleration energy is in the belts themselves. Local bumps of energy kick particles inside the belts to ever-faster speeds, much like a well-timed push on a moving swing. Knowing the location of the acceleration within the radiation belts will help scientists improve predictions of space weather, which can be hazardous to satellites near Earth. The results were published Thursday in the journal Science.

“Until the 1990s, we thought the Van Allen belts were pretty well-behaved and changed slowly,” says Geoff Reeves, lead author on the paper and a radiation belt scientist at Los Alamos National Laboratory in Los Alamos, N.M. “With more and more measurements, however, we realized how quickly and unpredictably the radiation belts change. They are basically never in equilibrium, but in a constant state of change.”

Full Story: http://www.nasa.gov/press/2013/july/nasa-mission-discovers-particle-accelerator-in-heart-of-van-allen-radiation-belts/#.UfFsW2Q4XB4

WIYN/NOAO: M51, The Whirlpool Galaxy, Seen With New ODI Camera On WIYN Telescope


Image credit: K. Rhode, M. Young and WIYN / NOAO / AURA / NSF

Image credit: K. Rhode, M. Young and WIYN / NOAO / AURA / NSF

The Whirlpool Galaxy (Messier 51) has been a popular night sky target for astronomers for centuries. Charles Messier first identified it in 1773 and listed it as number 51 in his catalog. To him, it looked like a faint, fuzzy object that might be a comet. William Parsons, the 3rd Earl of Rosse, used his 72-inch telescope “Leviathan” to observe the Whirlpool in 1845. Since then, Messier 51 has likely been targeted by virtually every telescope in the northern hemisphere. It is found in the constellation Canes Venatici (the Hunting Dogs) and is a classic example of a spiral galaxy.

Now, a new camera on the WIYN 3.5-meter telescope at Kitt Peak National Observatory has imaged the Whirlpool Galaxy anew. The wide field of the One Degree Imager (ODI) camera makes it possible to capture the entire galaxy and its companion in one pointing, something that even the Hubble Space Telescope cannot do.

“The WIYN telescope is an ideal telescope for the survey because of its wide field and because it produces some of the sharpest, highest-quality images possible with a ground-based telescope”, explained Indiana University (IU) astronomy professor Katherine Rhode. “WIYN’s 3.5-meter mirror is also very efficient at gathering light from astronomical objects, so it allows us to image faint objects, like individual star clusters within the galaxies.”

Full Story: http://www.noao.edu/news/2013/pr1309.php

CfA-Built Telescope On IRIS Sees First Light


Credit: NASA

Credit: NASA

NASA’s Interface Region Imaging Spectrograph (IRIS) observatory has produced its first images and spectra of a little understood region of the Sun through which the energy that supports the Sun’s hot corona is transported. IRIS was launched on June 27, 2013, and the front cover of the IRIS telescope was opened on July 17.

“Already, we’re finding that IRIS has the capability to reveal a very dynamic and highly structured chromosphere and transition region,” says astrophysicist Hui Tian of the Harvard-Smithsonian Center for Astrophysics (CfA). “Thin and elongated structures are clearly present in these first-light images, and they evolve quickly in time.”

Important goals of the IRIS mission are to understand how the Sun’s million degree corona is heated and to reveal the genesis of the solar wind.

Full Story: http://www.cfa.harvard.edu/news/2013/pr201321.html