Tag Archives: quasars

What lit up the universe?

New research from UCL shows we will soon uncover the origin of the ultraviolet light that bathes the cosmos, helping scientists understand how galaxies were built.

The study published in The Astrophysical Journal Letters by UCL cosmologists Dr Andrew Pontzen and Dr Hiranya Peiris (both UCL Physics & Astronomy), together with collaborators at Princeton and Barcelona Universities, shows how forthcoming astronomical surveys will reveal what lit up the cosmos. (more…)

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BOSS Quasars Unveil a New Era in the Expansion History of the Universe

Berkeley Lab scientists and their Sloan Digital Sky Survey colleagues use quasars to probe dark energy over 10 billion years in the past

BOSS, the Baryon Oscillation Spectroscopic Survey, is mapping a huge volume of space to measure the role of dark energy in the evolution of the universe. BOSS is the largest program of the third Sloan Digital Sky Survey (SDSS-III) and has just announced the first major result of a new mapping technique, based on the spectra of over 48,000 quasars with redshifts up to 3.5, meaning that light left these active galaxies up to 11.5 billion years in the past.

“No technique for dark energy research has been able to probe this ancient era before, a time when matter was still dense enough for gravity to slow the expansion of the universe, and the influence of dark energy hadn’t yet been felt,” says BOSS principal investigator David Schlegel, an astrophysicist in the Physics Division of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). “In our own time, expansion is accelerating because the universe is dominated by dark energy. How dark energy effected the transition from deceleration to acceleration is one of the most challenging questions in cosmology.” (more…)

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Pair of Black Holes ‘Weigh In’ At 10 Billion Suns, The Most Massive Yet

AUSTIN, Texas — A team of astronomers including Karl Gebhardt and graduate student Jeremy Murphy of The University of Texas at Austin have discovered the most massive black holes to date — two monsters weighing as much as 10 billion suns and threatening to consume anything, even light, within a region five times the size of our solar system.

The research is published in the Dec. 8 issue of the journal Nature in a paper headlined by  graduate student Nicholas McConnell and professor Chung-Pei Ma of the University of California, Berkeley. (more…)

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X-Ray Telescope Finds New Voracious Black Holes in Early Universe

ANN ARBOR, Mich.— Using the deepest X-ray image ever taken, a University of Michigan astronomer and her colleagues have found the first direct evidence that massive black holes were common in the early universe. This discovery from NASA’s Chandra X-ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies.

By pointing Chandra at a patch of sky for over six weeks, astronomers obtained what is known as the Chandra Deep Field South (CDFS). When combined with very deep optical and infrared images from NASA’s Hubble Space Telescope, the new Chandra data allowed astronomers to search for black holes in 200 distant galaxies, from when the universe was between about 800 million and 950 million years old. (more…)

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Measuring the Distant Universe in 3-D

*Berkeley Lab-led BOSS proves it can do the job with quasars*

The biggest 3-D map of the distant universe ever made, using light from 14,000 quasars — supermassive black holes at the centers of galaxies many billions of light years away — has been constructed by scientists with the third Sloan Digital Sky Survey (SDSS-III).

The map is the first major result from the Baryon Oscillation Spectroscopic Survey (BOSS), SDSS-III’s largest survey, whose principal investigator is David Schlegel of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). The huge new map was presented at the April meeting of the American Physical Society in Anaheim, CA, by Anže Slosar of Brookhaven National Laboratory. (more…)

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