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From Super To Ultra: Just How Big Can Black Holes Get?

December 24, 2012 Leave a comment

Credit: X-ray: NASA/CXC/Stanford/Hlavacek-Larrondo, J. et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA

Credit: X-ray: NASA/CXC/Stanford/Hlavacek-Larrondo, J. et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA

Some of the biggest black holes in the Universe may actually be even bigger than previously thought, according to a study using data from NASA’s Chandra X-ray Observatory. Astronomers have long known about the class of the largest black holes, which they call “supermassive” black holes. Typically, these black holes, located at the centers of galaxies, have masses ranging between a few million and a few billion times that of our sun.

This new analysis has looked at the brightest galaxies in a sample of 18 galaxy clusters, to target the largest black holes. The work suggests that at least ten of the galaxies contain an ultramassive black hole, weighing between 10 and 40 billion times the mass of the sun. Astronomers refer to black holes of this size as “ultramassive” black holes and only know of a few confirmed examples.

The researchers estimated the masses of the black holes in the sample by using an established relationship between masses of black holes, and the amount of X-rays and radio waves they generate. This relationship, called the fundamental plane of black hole activity, fits the data on black holes with masses ranging from 10 solar masses to a billion solar masses.

Full Story: http://www.chandra.harvard.edu/press/12_releases/press_121812.html

From Cassini For The Holidays: A Splendor Seldom Seen

December 24, 2012 Leave a comment

Image Credit: NASA/JPL-Caltech/Space Science Institute

Image Credit: NASA/JPL-Caltech/Space Science Institute

Just in time for the holidays, NASA’s Cassini spacecraft, in orbit around Saturn for more than eight years now, has delivered another glorious, backlit view of the planet Saturn and its rings.

On Oct. 17, 2012, during its 174th orbit around the gas giant, Cassini was deliberately positioned within Saturn’s shadow, a perfect location from which to look in the direction of the sun and take a backlit view of the rings and the dark side of the planet. Looking back towards the sun is a geometry referred to by planetary scientists as “high solar phase;” near the center of your target’s shadow is the highest phase possible. This is a very scientifically advantageous and coveted viewing position, as it can reveal details about both the rings and atmosphere that cannot be seen in lower solar phase.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2012-402
Also: http://www.ciclops.org/view/7418/A_Splendor_Seldom_Seen?js=1

WIYN/NOAO: A Panoramic Loop In Cygnus

December 24, 2012 Leave a comment

 

Credit: T.A. Rector (University of Alaska Anchorage) and WIYN/NOAO/AURA/NSF

Credit: T.A. Rector (University of Alaska Anchorage) and WIYN/NOAO/AURA/NSF

As an end of the year finale, the National Optical Astronomy Observatory (NOAO) and WIYN partners offer this new wide-field image of the Cygnus loop. Three degrees on a side, this image covers an area of the sky about 45 times that of the full moon. But it does so without sacrificing high resolution. The image is over 600 million pixels in size, making it one of the largest astronomical images ever made.

The Cygnus Loop is a large supernova remnant: the gaseous remains of a massive star that exploded long ago. It is located about 1,500 light-years from Earth in the direction of the constellation Cygnus, the Swan. Astronomers estimate the supernova explosion that produced the nebula occurred between 5,000 to 10,000 years ago. First noted in 1784 by William Herschel, it is so large that its many parts have been catalogued as separate objects, including NGC 6992, NGC 6995 and IC 1340 along the eastern (left) side of the image, NGC 6974 and NGC 6979 near the top-center, and the Veil Nebula (NGC 6960) and Pickering’s Triangle along the western (right) edge. The bright star near the western edge of the image, known as 52 Cygnus, is not associated with the supernova.

Fu;; Story: http://www.noao.edu/news/2012/pr1209.php
Image: http://www.noao.edu/image_gallery/html/im1138.html