Immediately after the Big Bang, the universe contained only hydrogen and helium. Heavier chemical elements had to be cooked up inside the first stars, then scattered throughout space to be incorporated in next-generation stars and their planets. Black holes may have helped to distribute those elements across the cosmos.

Black holes are not all-consuming monsters. Until gas crosses the boundary known as the event horizon, it can still escape if it is heated sufficiently.

"One of the big questions in cosmology is how much influence massive black holes exert on their surroundings," said co-author Martin Elvis of the Harvard-Smithsonian Center for Astrophysics (CfA). "This research helps answer that question."

An international team of astronomers has found that hot winds from giant black holes in galactic centers may blow heavy elements like carbon and oxygen into the vast tracts of space between galaxies.

The team, led by Yair Krongold of the Universidad Nacional Autonoma de Mexico, studied the supermassive black hole at the center of the galaxy NGC

4051. They found that gas was escaping from much closer to the black hole than previously thought. The outflow source is located about 2,000 Schwarzschild radii from the black hole, or about five times the size of Neptune's orbit. (The Schwarzschild radius is the black hole's "point of no return" - about 4 million miles for the black hole in NGC 4051.)

The team could also determine the fraction of gas that was avoiding being swallowed. That fraction ended up being smaller than earlier studies suggested.

"We calculate that between 2 to 5 percent of the accreting material is flowing back out," says team member Fabrizio Nicastro of the CfA.

Winds from black holes have been clocked at speeds of up to 4 million miles per hour. Over thousands of years, the chemical elements such as carbon and oxygen in those winds can travel immense distances, eventually becoming incorporated into the cosmic clouds of gas and dust, called nebulae, that will form new stars and planets.

This research, which used data from the European Space Agency's XMM-Newton satellite, is being reported in the April 20 issue of The Astrophysical Journal.

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Los Alamos National Laboratory
Scientists Discover Vast Intergalactic Cloud of Plasma Scientists explore the prospect of galactic black holes as sources of widespread magnetic fields Los Alamos NM (SPX) Apr 22 - Combining the world's largest radio telescope at Arecibo, Puerto Rico with a precision imaging, seven-antenna synthesis radio telescope at the Dominion Radio Astrophysical Observatory (DRAO), a team of researchers led by Los Alamos scientist Philipp Kronberg have discovered a new giant in the heavens, a giant in the form of a previously undetected cloud of intergalactic plasma that stretches more than 600 million light years across.

The diffuse, magnetized intergalactic zone of high energy electrons may be evidence for galaxy-sized black holes as sources for the mysterious cosmic rays that continuously zip though the Universe.

In research reported in the April issue of Astrophysical Journal, the team of researchers from Los Alamos, Arecibo, and DRAO in Penticton, British Columbia describe their discovery of a 2-3 megaparsec zone of diffuse, intergalactic plasma located beside the Coma cluster of galaxies.

The combined use of the 305 meter Arecibo radio telescope to make a base scan of 50 square degrees of sky, and the DRAO, making 24 separate 12 hour observations over 24 days of the same sky area, resulted in an image comparable to that of a 1000 meter diameter radio telescope. After Arecibo mapped the larger cloud structure, DRAO data was used to enhance the resolution of the image.

According to Kronberg, "One of the most exciting aspects of the discovery is the new questions it poses. For example, what kind of mechanism could create a cloud of such enormous dimensions that does not coincide with any single galaxy, or galaxy cluster?

Is that same mechanism connected to the mysterious source of the ultra high energy cosmic rays that come from beyond our galaxy? And separately, could the newly discovered fluctuating radio glow be related to unwanted foregrounds of the Cosmic Microwave Background (CMB) radiation?"

The synchrotron-radiating plasma cloud is spread across a vast region of space that may contain several black hole harboring radio galaxies. The cloud may be evidence that black holes in galaxies convert and transfer their enormous gravitational energy, by a yet unknown process, into magnetic fields and cosmic rays in the vast intergalactic regions of the Universe.

Kronberg's work also provides the first preview of small (arc minute - level) features that could be associated with unwanted and confusing foregrounds to the CMB radiation. Because these same radiation frequencies are to be imaged by the PLANCK CMB Explorer, corrections to the observed CMB for foreground fluctuations (the so-called microwave "cirrus clouds") are vitally important to using CMB fluctuations as a probe of the early Universe.

In addition to Kronberg, other members of the research team included, Roland Kothes from DRAO, and Christopher Salter and Phil Perillat from Arecibo and the National Astronomy and Ionosphere Center. The DRAO is operated by the Herzberg Institute of Astrophysics and the National Research Council of Canada.

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XMM-Newton pinpoints intergalactic polluters
Warm gas escaping from the clutches of enormous black holes could be the key to a form of intergalactic 'pollution' that made life possible, according to new results from ESA ' s XMM-Newton space observatory, published today.

Black holes are not quite the all-consuming monsters depicted in popular culture.

Until gas crosses the boundary of the black hole known as the Event Horizon, it can escape if heated sufficiently. For decades now, astronomers have watched warm gas from the mightiest black holes flowing away at speeds of 1000-2000 kilometres per second and wondered just how much gas escapes this way. XMM-Newton has now made the most accurate measurements yet of the process.

The international team of astronomers, led by Yair Krongold, Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, targeted a black hole two million times more massive than the Sun at the centre of the active galaxy NGC 4051.

Previous observations had only revealed the average properties of the escaping gas. XMM-Newton has the special ability to watch a single celestial object with several instruments at the same time. With this, the team collected more detailed information about variations in the gas' brightness and ionization state.

The team also saw that the gas was escaping from much closer to the black hole than previously thought. They could determine the fraction of gas that was escaping. "We calculate that between 2-5 percent of the accreting material is flowing back out," says team member Fabrizio Nicastro, Harvard-Smithsonian Centre for Astrophysics. This was less than some astronomers had expected.

The same heating process that allows the gas to escape also rips electrons from their atomic nuclei, leaving them ionised. The extent to which this has happened in an atom is known as its ionisation state. In particular, metals always have positive ionisation states.

The warm gas contains chemical elements heavier than Hydrogen and Helium. Astronomers term them 'metals; since they are elements in which electrons are ripped away and they have positive ionisation states - like metals.

They include carbon, the essential element for life on Earth. These metals can only be made inside stars, yet they pollute vast tracts of space between galaxies. Astronomers have long wondered how they arrived in intergalactic space.

This new study provides a clue. More powerful active galaxies than NGC 4051, known as quasars, populate space. They are galaxies in which the central hole is feeding voraciously. This would mean that quasars must have escaping gas that could carry metals all the way into intergalactic space.

If quasars are responsible for spraying metals into intergalactic space, the pollution would more likely be found in bubbles surrounding each quasar. So, different parts of the Universe would be enriched with metals at different speeds.

This may explain why astronomers see differing quantities of metals depending upon the direction in which they look.

However, if the fraction of escaping gas is really as low as XMM-Newton shows in NGC 4051, astronomers need to find another source of intergalactic metals. This might be the more prevalent star-forming galaxies called Ultra Luminous Infra Red Galaxies.

"Based on this one measurement, quasars can contribute some but not all of the metals to the intergalactic medium," says Krongold.

To continue the investigation, the astronomers will have to use the same XMM-Newton technique on a more powerful active galaxy. Such observations will allow them to determine whether the fraction of gas escaping changes or stays the same. If the fraction goes up, they will have solved the puzzle. If it stays the same, the search will have to continue.

The above results have been taken from the study 'The Compact, Conical, Accretion-Disk Warm Absorber of the Seyfert 1 Galaxy NGC 4051 and its Implications for IGM-Galaxy Feedback Processes' by Yair Krongold et al. Published 20 April, in the Astrophysical Journal.

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