Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Resolving a Galactic Mystery

01.05.2009
An extremely deep Chandra X–ray Observatory image of a region near the center of our Galaxy has resolved a long-standing mystery about an X-ray glow along the plane of the Galaxy.

The glow in the region covered by the Chandra image was discovered to be caused by hundreds of point-like X-ray sources, implying that the glow along the plane of the Galaxy is due to millions of such sources.


X-ray: NASA/CXC/TUM/M.Revnivtsev et al.; IR: NASA/JPL-Caltech/GLIMPSE Team

This extremely deep Chandra X--ray Observatory image has resolved a long-standing mystery about an X-ray glow along the plane of the Milky Way. The Chandra results show that the X-ray emission in the region is caused by hundreds of point-like sources, implying that the glow along the plane of the Galaxy is due to millions of such sources. In this image, the Chandra field-of-view, a region located only about 1.4 degrees from the Galactic Center, is pulled out from an infrared image from the Spitzer Space Telescope.

This image shows an infrared view from the Spitzer Space Telescope of the central region of the Milky Way, with a pullout showing a Chandra image of a region located only 1.4 degrees away from the center of the Galaxy.

The so-called Galactic ridge X-ray emission was first detected more than two decades ago using early X-ray observatories such as HEAO-1 and Exosat. The ridge was observed to extend about two degrees above and below the plane of the Galaxy and about 40 degrees along the plane of the galaxy on either side of the galactic center. It appeared to be diffuse.

One interpretation of the Galactic X-ray ridge was that it is emission from 100-million-degree gas. This interpretation is problematic because the disk of the Galaxy is not massive enough to confine such hot gas, which should flow away in a wind. Replenishing the gas would then be a problem, since plausible sources of energy such as supernovas are not nearly powerful enough.

A very deep Chandra observation, lasting for about 12 days, was used to study the nature of this ridge emission. The field was chosen to be close enough to the Galactic plane so that the ridge emission was strong, but in a region with relatively little absorption from dust and gas to maximize the number of sources that might be detected. A total of 473 sources were detected in an area on the sky only about 3% of the size of the full Moon, one of the highest densities of X-ray sources ever seen in our Galaxy.

It was found that more than 80% of the seemingly diffuse ridge of X-ray emission was resolved into individual sources. These are believed to be mostly white dwarfs pulling matter from companion stars and double stars with strong magnetic activity that are producing X-ray outbursts or flares that are similar to, but more powerful than the flares seen on the Sun. These stars are unrelated to the large-scale structures seen towards the center of the Spitzer image, which are probably caused by young massive stars.

The paper reporting these results appears in the April 30th issue of Nature. This work was led by Mikhail Revnivtsev from the Excellence Cluster Universe, Technical University Munich, in Garching, Germany, and from the Space Research Institute, in Moscow, Russia. The co-authors were Sergey Sasanov of the Space Research Institute in Moscow, Russia; Eugene Churazov of the Max Planck Institute for Astrophysics (MPA) in Garching, Germany; William Forman and Alexey Vikhlinin from the Harvard-Smithsonian Center for Astrophysics and Rashid Sunyaev from MPA.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

Megan Watzke | Newswise Science News
Further information:
http://www.cfa.harvard.edu

More articles from Physics and Astronomy:

nachricht Nanomagnetism in X-ray Light
23.03.2017 | Max-Planck-Institut für Intelligente Systeme

nachricht When helium behaves like a black hole
22.03.2017 | University of Vermont

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Vanishing capillaries

23.03.2017 | Health and Medicine

Nanomagnetism in X-ray Light

23.03.2017 | Physics and Astronomy

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>