Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Method Developed to Weigh, Resolve Distant Black Holes

04.06.2008
Arkansas Professor presents new, simple method to learn about black holes up to eight billion light years away.

Research presented to the American Astronomical Society meeting in St. Louis today offers astronomers a new, simple method to learn about black holes up to eight billion light years away – thousands of times farther away than black holes can be measured today.

Dr. Marc Seigar, assistant professor of physics and astronomy in the College of Science and Math at the University of Arkansas at Little Rock, and his research team have concluded that the larger the black hole at the center of a spiral galaxy, the tighter the galaxy’s arms wrap around itself. If correct, the simple relationship would give researchers an easy way to learn about black holes.

“This is a really easy way to determine the masses of these super-massive black holes at the centers of galaxies that are very far away,” Seigar said. “This gives us a way to measure the size of these far away black holes.”

Since super-massive black holes were discovered in nearby galaxies, researchers have been determining their masses by looking at how fast the stars were moving in the very central regions of those galaxies. But that method only works for relatively nearby galaxies, Seigar said.

“For more distant galaxies out to the distances we’re talking about, you have to develop alternative methods,” Seigar said. “And we have developed such a method.”

The method he described to the Astronomical Society involves taking a snapshot of a distant galaxy and measuring how tightly the spiral arms wrap around the galaxy, or the wrapping angle. He determined that the more massive the black hole, the tighter the spiral arms wrap around the galaxy, which indicates a small wrapping angle.

Seigar’s team studied photographs of 27 spiral galaxies, including our galaxy, the Milky Way, and its nearest neighbor, the Andromeda Galaxy. Galaxies with the smallest black holes had spiral arms with wrapping angles of up to 43 degrees. Those with biggest black holes had spiral arms at angles of only seven degrees between their central bulges.

“One of the important reasons to learn about the every distant black holes is, when you are looking at galaxies very far away, you are looking at them as they were in the past, so you can learn about how masses of black holes grow over time, ” Seigar said.

The black holes he is studying are super-massive black holes that are millions or billions times more massive than our sun. Since they seem to be found at the centers of all galaxies, they could be a key element of how galaxies form in the first place.

His studies also indicate that the mass of a black hole may depend on how centrally concentrated the dark matter is in a galaxy. “But that is a hypothesis that has yet to be proven,” he said. “We’re going to work on that.”

Seigar joined UALR’s faculty in 2007 following a stint as an assistant project scientist and McCue Fellow at the University of California-Irvine. His other experience includes postdoctoral research associate at the University of California-Irvine, adjunct professor at the University of Hawaii-Hilo, postdoctoral research associate at the University of London’s Imperial College and at Ghent University in Belgium. He also was a visiting astronomer at the Space Telescope Science Institute.

Seigar, who earned a Ph.D. in astrophysics at John Moores University in Liverpool, teaches Introduction to Astronomy at UALR as well as performing research in the structure, dynamics and star formation in spiral galaxies, and the nature of intracluster light in clusters of galaxies.

“Since my thesis I have been interested in the overall structure, morphology and dynamics of nearby galaxies, especially disk galaxies,” Seigar said.

He is involved in the Carnegie-Irvine Nearby Galaxies Survey (CINGS), a comprehensive optical and infrared imaging survey of the 600 brightest galaxies in the southern-hemisphere sky, being carried out at the 2.5-meter Du Pont telescope at Las Campanas Observatory. He is also involved in the Arkansas Galaxy Evolution Survey (AGES), part of which is to conduct a census of super-massive black holes in the universe.

To see photographs demonstrating Seigar’s paper can be found at http://www.ualr.edu/mxseigar/pics/Andromeda.jpg and http://www.ualr.edu/mxseigar/pics/Triangulum.jpg

Joan I. Duffy | newswise
Further information:
http://www.ualr.edu

More articles from Physics and Astronomy:

nachricht A tale of two pulsars' tails: Plumes offer geometry lessons to astronomers
18.01.2017 | Penn State

nachricht Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>