Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gone With the Galactic Wind: 10 Years of Chandra

15.03.2010
When NASA launched its Chandra X-ray observing telescope into orbit in 1999, astronomers didn’t know much about the galactic winds made of wispy, multi-million-degree gas clouds that stream out from normal galaxies like our own, because they are “diffuse, gentle and unspectacular” compared to far more dramatic emanations of starbursts, recalls astronomer Q. Daniel Wang of the University of Massachusetts Amherst.

But direct observation by the Chandra orbiting telescope have changed all that and led to “the first characterization of the spatial, thermal, chemical and kinetic properties of the gas in our galaxy,” Wang states.

Chandra data show, among other things, that though seemingly as ephemeral as fog, the outflowing hot gas from normal galaxies exerts a very powerful feedback force on the surroundings, preventing or slowing the infall of intergalactic gas due to gravity. “This discovery is a new key to our understanding of how galaxies work, especially how they lose mass and energy, that was not possible before Chandra,” he adds.

The astronomer catalogs the new knowledge in an article published this week in the early online edition of Proceedings of the National Academy of Sciences. Because his group has made extensive use of Chandra data, he was asked to write a review celebrating the instrument’s 10-year anniversary.

As Wang explains, galaxies like our own are made of visible stars and gas but investigating this matter and its properties using only visible light reveals only a small fraction of material actually present. “The hot gas is very hard to detect because of its low density, hence weak radiation, compared to black holes and neutron stars that accrete from their companions, which tend to overwhelm X-ray emissions from a galaxy,” he adds.

“By X-raying galaxies, we can see the invisible, and with the Chandra instrument we can detect gas that emits or absorbs X-rays, as well as such exotic objects as black holes and neutron stars that tend to emit primarily in X-rays.” X-ray tomography by the high-spectral resolution Chandra instrument has given astronomers the unprecedented opportunity to examine the amount, distribution and composition of the hot gas against bright background sources.

It has also helped to yield clues to the mystery of why there is not enough hot gas present inside or in the immediate vicinity of galaxies as predicted by current theory, in particular elements synthesized and ejected by stars. In fact, says Wang, “we find that the bulk of energy expected from the supernovae is missing as well. We conclude that this missing energy is gone with the wind, a galactic wind that blows matter to much larger regions around galaxies than previously understood.”

“Indeed, we find direct evidence for such winds and outflows in nearby galaxies. This uses another well-known capability of the Chandra, the exquisite spatial resolution, which allows us to detect discrete X-ray sources and to remove them cleanly when mapping X-ray emission in and around galaxies. The outflows are called galactic feedback, which can have profound impact on the ecosystem of the galaxies.”

“These results, compared with detailed simulations, now enable us to study how the feedback regulates the formation and evolution of galaxies,” Wang says.

Daniel Wang
413/545-2131
wqd@astro.umass.edu

Daniel Wang | Newswise Special Wire
Further information:
http://www.umass.edu

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

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: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>