Last updated on April 17, 2014 at 14:29 EDT

Latest Active galactic nucleus Stories

2011-05-03 06:30:00

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 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...

2011-03-02 13:39:54

Using a perfectly orchestrated world-wide network of radio telescopes, astronomers have produced a high-resolution map of an Active Galactic Nucleus (AGN) belonging to an unknown class of gamma-ray sources. The unusual source and the groundbreaking technique used to produce the image are detailed in a letter published today in Astronomy & Astrophysics. The paper, "Global e-VLBI observations of the gamma-ray narrow line Seyfert 1 PMN J0948+0022" (abstract, full html, PDF), presents very...

2011-02-25 11:55:00

When two galaxies merge to form a giant, the central supermassive black hole in the new galaxy develops an insatiable appetite. However, this ferocious appetite is unsustainable. For the first time, observations with the Gemini Observatory clearly reveal an extreme, large-scale galactic outflow that brings the cosmic dinner to a halt. The outflow is effectively blowing the galaxy apart in a negative feedback loop, depriving the galaxy's monstrous black hole of the gas and dust it needs to...

2011-01-20 12:53:49

Seen in X-rays, the entire sky is aglow. Even far away from bright sources, X-rays originating from beyond our galaxy provide a steady glow in every direction. Astronomers have long suspected that the chief contributors to this cosmic X-ray background were dust-swaddled black holes at the centers of active galaxies. The trouble was, too few of them were detected to do the job. An international team of scientists using data from NASA's Swift satellite confirms the existence of a largely unseen...

2011-01-12 13:44:18

Astronomers at the California Institute of Technology (Caltech), University of Illinois at Urbana-Champaign (UIUC), and University of Hawaii (UH) have discovered 16 close-knit pairs of supermassive black holes in merging galaxies. The discovery, based on observations done at the W. M. Keck Observatory on Hawaii's Mauna Kea, is being presented in Seattle on January 12 at the meeting of the American Astronomical Society, and has been submitted for publication in the Astrophysical Journal. These...

2011-01-10 08:29:08

Discovery gives important clues about a previously-unobserved, very early phase of galaxy evolution The surprising discovery of a supermassive black hole in a small nearby galaxy has given astronomers a tantalizing look at how black holes and galaxies may have grown in the early history of the Universe. Finding a black hole a million times more massive than the Sun in a star-forming dwarf galaxy is a strong indication that supermassive black holes formed before the buildup of galaxies, the...

2011-01-05 07:50:00

What happens when galaxies crash together? For years, these cosmic collisions have been blamed for triggering violent outbursts at the hearts of galaxies. Now, a remarkable piece of detective work has given a verdict: galactic mergers do not usually whet the appetite of the black holes that power these active galactic nuclei, meaning other, less dramatic phenomena are responsible. Most galaxies, including our own, have a huge but well-behaved black hole at their heart, while some have messy...

2010-12-20 14:57:21

A new study from NASA's Chandra X-ray Observatory tells scientists how often the biggest black holes have been active over the last few billion years. The object could help scientists better understand how massive stars explode, which ones leave behind black holes or neutron stars, and how many black holes are in our galaxy and others. This discovery clarifies how supermassive black holes grow and could have implications for how the giant black hole at the center of the Milky Way will behave...

2010-11-25 06:36:54

New findings disagree with current models Some of the universe's most massive galaxies may have formed billions of years earlier than current scientific models predict, according to surprising new research led by Tufts University. The findings appear in the Astrophysical Journal published online Nov. 24 in advance of print publication on Dec. 10, 2010. "We have found a relatively large number of very massive, highly luminous galaxies that existed almost 12 billion years ago when the universe...

2010-07-01 06:20:00

Evidence for a recoiling black hole has been found using data from the Chandra X-ray Observatory, XMM-Newton, the Hubble Space Telescope (HST), and several ground-based telescopes. This black hole kickback was caused either by a slingshot effect produced in a triple black hole system, or from the effects of gravitational waves produced after two supermassive black holes merged a few million years earlier. The discovery of this object, located in this composite image, comes from a large,...

Latest Active galactic nucleus Reference Libraries

2004-10-19 04:45:42

Seyfert Galaxy -- Seyfert galaxies are spiral or irregular galaxies containing an extremely bright nucleus, most likely caused by a supermassive black hole, that can sometimes outshine the surrounding galaxy. The light from the central nucleus varies in less than a year, which implies that the emitting region must be less than one light year across. They are named for the astronomer Carl Seyfert, who studied them extensively in the 1940s. They are a subclass of active galactic nuclei....

2004-10-19 04:45:42

Quasar -- A quasar (from quasi-stellar radio source) is an astronomical object that looks like a star in optical telescopes (i.e. it is a point source), but has a very high redshift. The general consensus is that this high redshift is cosmological, the result of Hubble's law and that their redshift indicates that they are typically very distant from Earth; we observe them as they were several billions of years ago. Since we can see them despite their distance, they must emit more...

2004-10-19 04:45:41

Active Galaxy -- An active galaxy is a galaxy where a significant fraction of the energy output is not emitted from normal stellar populations or interstellar gas. This energy, depending on the active galaxy type, can be emitted across most of the electromagnetic spectrum, as infrared, radio waves, UV, X-ray and gamma rays. Frequently, the abbreviation AGN (Active Galactic Nuclei) is used, since most of the active galaxies emit most of their radiation from a narrow region in their...

2004-10-19 04:45:40

Circinus Galaxy -- Resembling a swirling witch's cauldron of glowing vapors, the black hole-powered core of a nearby active galaxy appears in this colorful NASA Hubble Space Telescope image. The galaxy lies 13 million light-years away in the southern constellation Circinus. This galaxy is designated a type 2 Seyfert, a class of mostly spiral galaxies that have compact centers and are believed to contain massive black holes. Seyfert galaxies are themselves part of a larger class of objects...

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