Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UCLA astronomers detect plasma at black hole

05.09.2003


UCLA astronomers report they have detected remarkably stormy conditions in the hot plasma being pulled into the monstrous black hole residing at the center of our Milky Way galaxy, 26,000 light years away. This detection of the hot plasma is the first in an infrared wavelength, where most of the disturbed plasma’s energy is emitted, and was made using the 10-meter Keck II Telescope at the W.M. Keck Observatory in Hawaii.



Plasma is a hot, ionized, gas-like matter -- a fourth state of matter, distinct from solids, liquids and gases -- believed to make up more than 99 percent of the visible universe, including the stars, galaxies and the vast majority of the solar system.

"Previous observations at radio and X-ray wavelengths suggested that the black hole is dining on a calm stream of plasma that experiences glitches only 2 percent of the time," said Andrea Ghez, professor of physics and astronomy at UCLA, who headed the research team. "Our infrared detection shows for the first time that the black hole’s meal is more like the Grand Rapids, in which energetic glitches from shocked gas are occurring almost continually."


"I see this as a real breakthrough," said Mark Morris, a UCLA professor of physics and astronomy, who worked with Ghez. "It’s a big leap, not just an incremental advance. The infrared is precisely where we need to look to learn what the black hole is eating. In the infrared, you see it all. The black hole’s dirty laundry is hanging right there for us to see. We’re peering deep down inside this tumultuous region."

"One of the big mysteries in studies of the black hole at the center of our galaxy is why the surrounding gas is emitting so little light compared to black holes at the center of other galaxies," Ghez said. "We now have a completely new and continuously open window to study the material that is falling onto the black hole at the center of the Milky Way."

The past two years, Ghez and her colleagues used adaptive optics at the Keck Observatory to get high-resolution images at wavelengths between the short near-infrared, where stars dominate, and the mid-infrared, where dust dominates.

"There’s a history of false detections of this source in the infrared," Ghez said. "At short wavelengths, it’s challenging because there are so many stars. In the mid-infrared, it’s difficult because there is so much dust at the center of the galaxy. Our observation was successful because it was made between these two problematic regimes with an adaptive optics system. This type of observation only became possible last year."

"We are highly confident in our detection," Ghez added. "We have a bright source at exactly the right spot, right on the black hole, and with properties that are unlike the stars around it; the source emits much more strongly at long wavelengths than the stars, and the source doesn’t move, while the stars move at huge velocities. What’s exciting and important is not just that we detected the plasma, but that it varies dramatically in intensity from week-to-week, day-to-day, and even within a single hour. It’s as if we have been watching the black hole breathing."

Black holes are collapsed stars so dense that nothing can escape their gravitational pull, not even light. Black holes cannot be seen directly, but their influence on nearby stars is visible, and provides a signature, Ghez said. The black hole, with a mass more than three million times that of our sun, is in the constellation of Sagittarius.

Since 1995, Ghez has been using the W.M. Keck Observatory’s 10-meter Keck I Telescope atop Mauna Kea in Hawaii -- the world’s largest optical and infrared telescope -- to study the galactic center and the movement of 200 nearby stars. She has made measurements using a technique she refined called infrared speckle interferometry, and for the last few years, has used adaptive optics, an even more sophisticated technique, which enables her to see the region more clearly.

"The Keck Observatory is one of the best facilities in the world for this research," Ghez said.

The astronomers know the location of the black hole so precisely "that it’s like someone in Los Angeles who can identify where someone in Boston is standing to within the width of her hand, if you scale it out to 26,000 light years," Ghez said. The galactic center is located due south in the summer sky.

The black hole at the center of our galaxy came into existence billions of years ago, perhaps as very massive stars collapsed at the end of their life cycles and coalesced into a single, supermassive object.

For decades, the emission at the galactic center could be detected only in radio wavelengths, which do not reveal the variations in intensity. "The radio is partially opaque," Morris said. The emission was detected for the first time recently in the X-way wavelengths, but it is important to now have the detection between these two wavelength extremes, where details of the plasma can be seen. In the X-ray, activity can be seen only about 5 percent of the time, while in the infrared, it can be seen continually, Morris said.

The astronomers are learning what is causing gas to emit radiation as it approaches and enters the black hole. Ghez and her colleagues will continue to study the supermassive black hole at a variety of near infrared wavelengths.

Ghez’s co-authors include Morris; UCLA physics and astronomy professor Eric Becklin, who identified the center of the Milky Way in 1968; California Institute of Technology research scientist Keith Matthews, and UCLA graduate student Shelley Wright.


###
The research is federally funded by an individual grant to the National Science Foundation, the National Science Foundation’s Center for Adaptive Optics, and the Packard Foundation. It has been submitted for publication to the Astrophysical Journal Letters and is available at http://xxx.lanl.gov/abs/astro-ph/0309076. Ghez also will present her findings Sept. 24 in an invited talk at the 4th Cologne-Bonn-Zermatt Symposium on The Dense Interstellar Medium in Galaxies in Zermatt, Switzerland.

Stuart Wolpert | EurekAlert!
Further information:
http://www.astro.ucla.edu/research/galcenter/

More articles from Physics and Astronomy:

nachricht NASA Protects its super heroes from space weather
17.08.2017 | NASA/Johnson Space Center

nachricht New thruster design increases efficiency for future spaceflight
16.08.2017 | American Institute of Physics

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

NASA Protects its super heroes from space weather

17.08.2017 | Physics and Astronomy

Spray-on electric rainbows: Making safer electrochromic inks

17.08.2017 | Materials Sciences

Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

17.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>