Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New technique for ‘weighing’ black holes

ESA's XMM-Newton has helped to find evidence for the existence of controversial Intermediate Mass Black Holes. Scientists used a new, recently proven method for determining the mass of black holes.

Nikolai Shaposhnikov and Lev Titarchuk, at NASA’s Goddard Space Flight Center (GSFC), have used the technique to determine the mass of the black hole, Cygnus X-1, located in the constellation Cygnus (the Swan) approximately 10 000 light years away in our Galaxy, the Milky Way.

The elegant technique, first suggested by Titarchuk in 1998, shows that Cygnus X-1, part of a binary system, contains 8.7 solar masses, with a margin of error of only 0.8 solar masses. Cygnus X-1 was one of the first compelling black hole candidates to emerge in the early 1970s. The system consists of a blue supergiant and a massive but invisible companion.

Alternative techniques have previously suggested that the invisible object was a black hole of about 10 solar masses. “This agreement gives us a lot of confidence that our method works,” says Shaposhnikov. It can help determine a black hole’s mass when alternative techniques fail,” adds Titarchuk.

Working independently from Shaposhnikov and Titarchuk, Tod Strohmayer and Richard Mushotzky, also from GSFC, and four colleagues, used Titarchuk’s technique on XMM data and stumbled upon an Intermediate Mass Black Hole (IMBH)- the existence of which is in theory controversial.

They estimated that an ultraluminous X-ray source in the nearby galaxy, NGC 5408, harbours a black hole with a mass of about 2 000 Suns.“This is one of the best indications to date for an IMBH,” says Strohmayer.

The existence of IMBHs is controversial because there is no widely accepted mechanism for how they could form. But they would fill in a huge gap between black holes such as Cygnus X-1 - which form from collapsing massive stars and contain perhaps 5 to 20 solar masses - and the 'monsters' (up to thousand million solar masses) that lurk in the cores of large galaxies.

Titarchuk’s method takes advantage of a relationship between a black hole and its surrounding accretion disk. Gas orbiting in these disks eventually spirals into the black hole. When a black hole’s accretion rate increases to a high level, material piles up near the black hole in a hot region that Titarchuk likens to a traffic jam.

Titarchuk has shown that the distance from the black hole where this congestion occurs scales directly with the mass of the black hole. The more massive the black hole, the farther this congestion occurs and the longer the orbital period.

In his model, hot gas piling up in the congestion region is linked to observations of X-ray intensity variations that repeat on a nearly, but not perfectly, periodic basis. These Quasi-Periodic Oscillations (QPOs) are observed in many black hole systems. The QPOs are accompanied by simple, predictable changes in the system’s spectrum as the surrounding gas heats and cools in response to the changing accretion rate.

Precise timing observations from NASA’s Rossi X-ray Timing Explorer (RXTE) satellite have shown a close relationship between the frequency of QPOs and the spectrum, telling astronomers how efficiently the black hole is producing X-rays.

Using RXTE, Shaposhnikov and Titarchuk have applied this method to three stellar-mass black holes in the Milky Way and shown that the derived masses from the QPOs concur with mass measurements from other techniques.

Using ESA's XMM-Newton X-ray observatory, Strohmayer, Mushotzky, and their colleagues detected two QPOs in NGC 5408 X-1.

NGC 5408 X-1 is the brightest X-ray source in the small, irregular galaxy NGC 5408, 16 million light years from Earth in the constellation Centaurus. The QPO frequencies, as well as the luminosity and spectral characteristics of the source, imply that it is powered by an IMBH.

“We had two other ways of estimating the mass of the black hole, and all three methods agree within a factor of two,” says Mushotzky. “We don’t have proof this is an IMBH, but the preponderance of evidence suggests that it is.”

One of the study’s coauthors, Roberto Soria of the Harvard-Smithsonian Center for Astrophysics, thinks the black hole’s mass is closer to one hundred Suns.

Norbert Schartel | alfa
Further information:

More articles from Physics and Astronomy:

nachricht First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory

nachricht Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters

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: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

Gene therapy shows promise for treating Niemann-Pick disease type C1

27.10.2016 | Life Sciences

Solid progress in carbon capture

27.10.2016 | Power and Electrical Engineering

More VideoLinks >>>