Skip navigation Chandra, the ultimate X-ray machine
POSTED 5 SEP 2002
 

 

RELATED WHY FILES:
Hubble's greatest hits
X-ray astronomy
Infrared astronomy
Radio astronomy

Note: Colors in the images represent different X-ray energies.

Red: low.
Green: medium.
Blue: high.

 

 

 

 

 

 

 

Right: Chandra image shows the beautiful, complex remnant of a massive star (N132D) that exploded in the Large Magellanic Cloud, a galaxy about 180,000 light years distant. This supernova remnant contains expanding junk from the star, and the nearby matter it is colliding with. The horseshoe shape is probably due to shock waves from a collision between the expanding trash and giant clouds of cool gas. The shock waves heat the gas to millions of degrees, producing the glowing X-ray shell.

All photos from NASA.

 

 

 

 

 

 

Below: It's not the humidity, it's the heat! By pasting up several Chandra images of the center of our Milky Way galaxy, scientists concocted this massive mosaic, 400 light years tall by 900 light years across. Inside, hundreds of white dwarf stars, neutron stars, and black holes are bathed in the incandescent fog of multimillion-degree gas. The black hole at the center of the galaxy is inside the bright white patch in the center.

NASA/UMass/D. Wang et al.

Vertical picture shows series of white, blue and red spots across the center. Hazy white veil partly obscures the brightest objects, at galactic center.

 

 

 

 

 

 

 

 

 

Right: No, it's not a brain -- it's the aftermath of a massive star explosion. G292.0+1.8 is a young supernova remnant with a central pulsar surrounded by outflowing material. Pulsars are formed in supernova explosions, but astronomers don't know which types of massive stars are raw material for pulsars. The pattern of elements seen here should help astronomers trace the ancestry of pulsars.

NASA/CXC/Rutgers/J. Hughes et al.

 

Visions of a spectacular three-year-old
Chandra, the X-ray telescope launched into orbit in July, 1999, has just passed its third birthday. As you'll see, it's made some shockingly pretty pictures. And even though we Why Filers are suckers for a pretty picture, we decided to ask someone who actually knew something about X-ray astronomy.

We contacted Roger Blandford, a professor of theoretical astrophysics at California Institute of Technology, to ask how the three-year-old is doing. He told us Chandra has made significant discoveries in a number of areas:

The ultra-fast jets of gas that may stretch for hundreds of thousands of light years from active galaxies or quasars. Due to Chandra's excellent angular resolution (ability to distinguish nearby objects) the ‘scope shows that, oddly, particles may accelerate after entering the jet. "There is a flow of energy along the jet that is capable of making these very high-energy electrons all along the jet," says Blandford. "That's a somewhat different view from previously.

Chandra has also observed hundred-million-degree gas between galaxies in galactic clusters, and undergirded new estimates of the amount of dark matter and dark energy in the universe. According to the latest calculations emanating from Chandra, optical instruments, and physics theory, conventional matter accounts for only 4 percent of the mass of the universe. At this point, our advice is to stand back as the ultimate X-ray machine continues to crank out amazing science. All we can add is that we only wish every three-year-old could hold a camera this steadily!

Looking like a horseshoe, the clouds of gas are interspersed with bright spots, indicating star formation.
From a selfish point of view, nothing is more important than past supernovas. Stars routinely fuse hydrogen into helium, but they don't make appreciable amounts of heavier elements like oxygen, carbon and nitrogen. Those elements only form during the cataclysmic explosion of a supernova.

X-ray observations of supernova remnants like this, says Blandford, show "highly processed material and evidence for lots of nuclear reactions. The supernova disseminates all this cooked material that enriches the interstellar medium, it's what we're made of." X-ray astronomy is a natural way to investigate these hot remnants, he adds. "You see the proportions and locations of different elements. We're starting to reconstruct the supernova explosion, and understand which elements are made, and how and where they are made."

At center are 2 tiny white specs, surrounded by a cross-shaped region of high temperature. Various points indicate hot regions, either stars or star formation.

Chandra's snapshots of this black hole show it to be rather anemic, says Blandford. Not only will the black hole fail to devour the entire Milky Way, but "it's not eating anything at the moment. What's remarkable is how underluminous it is, it's pathetic, but Chandra can still see it."

Two areas of star formation show blue, white, red, violet regions, indicating arcs, points and veils of hot gas and stars.

Snapshots like this allow astronomers to study starbursts -- episodes of rapid star formation that play a key role in galactic evolution. At least 11 extremely massive stars with ages of about 2 million years are in the bright cluster in the center.

A cobweb of energy, whitish in the center, and golden toward the outside, reflects different temperatures. Overall effect is like a brain, seen from the top.

The rapidly expanding shell of gas, 36 light years across, contains a gazillion freight cars worth of oxygen, neon, magnesium, silicon and sulfur. With an estimated age of 1,600 years, this is one of three known oxygen-rich supernovae in our galaxy.

-- David Tenenbaum

 

 

     

BIBLIOGRAPHY
Chandra @ Harvard
Chandra @ NASA
Chandra's greatest hits

 
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