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Archive for July 30, 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