Cookie cutter in the sky

December 16, 2008

Black holes can now be thought of as donut holes. The shape of material around black holes has been seen for the first time: an analysis of over 200 active galactic nuclei--cores of galaxies powered by disks of hot material feeding a super-massive black hole--shows that all have a consistent, ordered physical structure that seems to be independent of the black hole's size.

"This should be a very messy and complicated environment, but the stuff flowing onto different black holes looks the same, no matter how massive the black hole is," says Barry McKernan, a Research Associate in Astrophysics at the American Museum of Natural History and a professor at the Borough of Manhattan Community College, City University of New York. "This observed shape should constrain all our ideas as to how the glow around black holes is produced, and if we can handle the stuff around black holes, we can begin to study black holes themselves."

Although black holes cannot be seen directly, the hot material swirling around super-massive black holes can be observed. In this paper, McKernan and colleagues tested a hypothesis about the relationship between two extremes of radiation coming from around super-massive black holes: X-rays should come from very hot material close to the black hole, and infrared light should come from warm material much further from the hole. This pattern allowed them to tell if matter around the black hole was being observed face-on (looking directly down onto the black hole ringed by X-rays and infrared light) or edge-on (seeing only the side of the donut of material). Some of the infrared light should also come from part of the donut that has been fried by X-ray bombardment. By comparing the proportion of X-rays to infrared light coming from around a black hole, it is possible to indirectly figure out how material may be distributed around the black hole.

McKernan and colleagues looked at a large sample size of 245 active galactic nuclei containing black holes between 1 million and 100 million times heavier than the sun. All of these active galactic nuclei have been described, and data is available through the NASA/IPAC Extragalactic Database. After partitioning the systems into those observed edge-on and those observed face-on, the team found that 90% of the active galactic nuclei observable face-on had basically the same proportion of X-rays to infrared light.

"Because the data points in the infrared range are from the old Infrared Astronomical Satellite, we can say this is not a infrared-biased sample because the satellite looked at all of the sky," says coauthor K.E. Saavik Ford, also a Research Associate in Astrophysics at AMNH and a professor at BMCC, CUNY. "It is interesting to learn something about black holes as a class."

McKernan agrees. "Now we know they all look like donuts, and the same kind of donut too. The lack of variety would disappoint Homer Simpson."
-end-
The research is published in Monthly Notices of the Royal Astronomical Society. Coauthors include Nathan Chang, an undergraduate at BMCC, CUNY, and Chris Reynolds, Associate Professor in the Department of Astronomy, University of Maryland College Park. Grants from NASA and the City University of New York funded the research, and research was carried out in the Department of Astrophysics at AMNH.

American Museum of Natural History

Related Black Hole Articles from Brightsurf:

Black hole or no black hole: On the outcome of neutron star collisions
A new study lead by GSI scientists and international colleagues investigates black-hole formation in neutron star mergers.

The black hole always chirps twice: New clues deciphering the shape of black holes
A team of gravitational-wave scientists led by the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) reveal that when two black holes collide and merge, the remnant black hole 'chirps' not once, but multiple times, emitting gravitational waves--intense ripples in the fabric space and time--that inform us about its shape.

Wobbling shadow of the M87 black hole
New analysis from the Event Horizon Telescope (EHT) Collaboration reveals the behavior of the supermassive black hole in the center of the M87 galaxy across multiple years, indicating the crescent-like shadow feature appears to be wobbling.

How to have a blast like a black hole
Scientists at Osaka University have created magnetized-plasma conditions similar to those near a black hole using very intense laser pulses.

Black hole collision may have exploded with light
Astronomers have seen what appears to the first light ever detected from a black hole merger.

Black hole's heart still beating
The first confirmed heartbeat of a supermassive black hole is still going strong more than ten years after first being observed.

Black hole team discovers path to razor-sharp black hole images
A team of researchers have published new calculations that predict a striking and intricate substructure within black hole images from extreme gravitational light bending.

Planets around a black hole?
Theoreticians in two different fields defied the common knowledge that planets orbit stars like the Sun.

Black hole mergers: Cooking with gas
Gravitational wave detectors are finding black hole mergers in the universe at the rate of one per week.

Going against the flow around a supermassive black hole
At the center of a galaxy called NGC 1068, a supermassive black hole hides within a thick doughnut-shaped cloud of dust and gas.

Read More: Black Hole News and Black Hole Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.