Black Hole Feeding Frenzy

by Paul Gilster on July 27, 2007

A research team using data from the Chandra x-ray observatory has examined supermassive black hole activity in galaxy clusters of different ages. Also known as active galactic nuclei (AGN), the black holes are the result of rapid growth in gas-rich environments in the early universe, explaining why they are more common in young clusters than in older ones. Comparing the fraction of AGN in clusters at large distance (when the universe was 58 percent of its current age) to relatively nearby clusters, the team found 20 times more AGN in the more distant sample.

Paul Martini (Ohio State University) sees this as confirmation of earlier theory:

“It’s been predicted that there would be fast-track black holes in clusters, but we never had good evidence until now. This can help solve a couple of mysteries about galaxy clusters.”

Mysteries such as why the number of blue, star-forming galaxies seems to diminish as we move to nearer, older galactic clusters. The process would seem to involve supermassive black holes expelling gas from their host galaxy through powerful eruptions, stifling the star formation process so that only older, redder stars are left. That sequence is thought to consume about a billion years. Says Jason Eastman, also of OSU:

“In a few nearby clusters we’ve seen evidence for huge eruptions generated by supermassive black holes. But this is sedate compared to what might be going on in younger clusters.”

Active galactic nuclei

Keep going back in time and it appears that AGN may be still more common around ten billion years ago, when most of these clusters were forming. As we learn more about the enigmatic black holes at the center of some galaxies, we’re beginning to understand how influential they must be in shaping the development of the galaxy clusters in which they reside. Supermassive black holes can be found outside clusters as well (more commonly in the early universe), but they do not appear nearly as frequently as in the cluster environment.

Image: An artist’s conception of a rapidly growing black hole, otherwise known as an active galactic nucleus (AGN), in the center of a galaxy. A disk of hot gas is flowing into a central black hole, and is surrounded by a large doughnut or torus of cooler gas and dust. Earlier in the history of the universe, galaxies in clusters of galaxies are thought to have contained a lot more gas than galaxies in clusters do today. This abundance of fuel should mean that the piranha-like black holes were able to thrive in young, distant clusters by growing much faster than their counterparts in nearby clusters. Chandra observations have confirmed this by showing, for the first time, that there are more AGN in younger, more distant galaxy clusters. This illustration also shows jets of high energy particles (white) that are propelled away from the vicinity of the black hole by intense electric and magnetic fields. These jets can heat the gas in galaxy clusters and significantly affect their structure. Credit: NASA/CXC/M.Weiss.

The paper is Eastman et al., “First Measurement of a Rapid Increase in the AGN Fraction in High-Redshift Clusters of Galaxies,” Astrophysical Journal Vol. 664 (July 20, 2007), pp. L9-L12 (abstract).

philw July 29, 2007 at 15:29

Why does this article make me think of “The Little Shop of Horrors’? FEED ME!

ljk September 20, 2007 at 9:47

Did the big bang spawn trillions of black holes? news service Sept. 19, 2007


Were vast numbers of black holes
spawned during our universe’s
earliest moments? So far, there is
no hard evidence that such
primordial black holes (PBHs) ever
existed, but new observations just
around the corner could change that.

The black holes emit X-rays that can
escape the vicinity of the black
holes to ionize hydrogen atoms. This

ljk October 19, 2007 at 11:31


Date: Thu, 18 Oct 2007 05:02:21 GMT (8kb)

Title: Can one detect passage of small black hole through the Earth?

Authors: I.B. Khriplovich, A.A. Pomeransky, N. Produit, G.Yu. Ruban

Categories: astro-ph

Comments: 6 pages

The energy losses of a small black hole passing through the Earth are
examined. In particular, we investigate the excitations in the frequency range
accessible to modern acoustic detectors. The main contribution to the effect is
given by the coherent sound radiation of the Cherenkov type. , 8kb

ljk January 9, 2008 at 9:48



Hirosi Ooguri, the Kavli Professor of Theoretical Physics at
Caltech, is a corecipient of the first ever Leonard Eisenbud Prize
for Mathematics and Physics, awarded by the American Mathematical
Society (AMS). The prize, created in 2006, has gone to Ooguri and
coauthors Andrew Strominger and Cumrun Vafa of Harvard University
for their paper “Black hole attractors and the topological string,”
published in 2004.


ljk January 10, 2008 at 11:32

Rogue Black Holes Might Fill Our Galaxy

By Jeanna Bryner

Staff Writer

posted: 09 January 2008

12:30 p.m. ET

AUSTIN, Texas — Our home galaxy could be chockfull
of rogue black holes that devour anything that crosses
their paths, new computer simulations suggest.

Full article here:

ljk January 15, 2008 at 16:17

Black Holes Spin Near Speed of Light

By Jeremy Hsu

Staff Writer

posted: 15 January 2008, 06:38 am ET

Supermassive black holes spin at speeds approaching
the speed of light, new research suggests.

Nine huge galaxies were found to contain furiously
whirling black holes that pump out energetic jets of
gas into the surrounding environment, according to
a study using data from NASA’s Chandra X-ray

“We think these monster black holes are spinning close
to the limit set by Einstein’s theory of relativity, which
means that they can drag material around them at
close to the speed of light,” said Rodrigo Nemmen,
the study’s lead author and a visiting graduate student
at Penn State University.

Einstein’s theory suggests spinning black holes would
make space itself rotate. The overall effect makes gas
spiral in toward the black hole, and also creates a
magnetic field that shoots inflowing gas back out as a jet

Full article here:

James M. Essig May 29, 2008 at 17:50

Hi ljk;

Interesting series of summarized articles above.

Black holes can be an enormous energy source especially the super massive black holes that are located within the center of galaxies. I have read that objects falling near a black hole with the appropriate trajectory simply get kicked back out away from the black hole at relativistic velocities.

I can imagine that a super massive black hole spinning at almost C could be used to produce relativistic kinetic energy gains for materials that “fall into” the black hole and are flung away at velocities approaching C. Naturally, the black hole would have a slight recoil velocity for small macroscopic masses that are tossed. However, after billions if not quadrillions of years of using a central galactic black hole as a general relativistic energy source wherein large quantities of matter have been accelerated to relativistic velocities after being launch in near grazing incidence trajectories around the event horizon, wherein the black hole would begin to drift from its central location by acquiring recoil momentum, the other side of the black hole could be utilized as the region for near grazing incidence in order to reverse the black hole drift.

As the black hole lost mass as a result of Hawking Radiation over roughly 10 EXP 100 years, it could be restocked with injected or infalling matter. What a beautifully elegant energy supply super massive black holes could make for human and ETI civilizations that would exist for cosmic epochs into the future.



ljk August 3, 2008 at 23:53

The minimum mass of a black hole that is capable of accreting a particle

Authors: Scott Funkhouser

(Submitted on 11 Jul 2008 (v1), last revised 24 Jul 2008 (this version, v3))

Abstract: If a black hole should absorb a fundamental particle then the number of bits registered by the black hole must increase by at least one. It follows that the minimum mass of a Schwarzschild black hole that is capable of absorbing a massive particle is inversely proportional to the mass of the particle. That stipulation is identical to the limit obtained by applying Landauer’s Principle to the accretion of a particle.

The minimum Schwarzschild mass necessary for the accretion of nucleons is of the order 10^9kg. Since the minimum mass necessary for accreting electrons is roughly three orders of magnitude larger than the minimum mass necessary for the accretion of protons, it is conceivable that certain black holes could accumulate electrical charge.

Comments: 3 pages; removed discussion of cosmo.constant(reserved for separate paper); added derivation of result from Landauer’s principle

Subjects: General Physics (physics.gen-ph)

Cite as: arXiv:0807.1938v3 [physics.gen-ph]

Submission history

From: Scott Funkhouser [view email]

[v1] Fri, 11 Jul 2008 22:02:31 GMT (148kb)

[v2] Sun, 20 Jul 2008 21:32:53 GMT (401kb)

[v3] Thu, 24 Jul 2008 16:41:57 GMT (219kb)

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