X-ray cameras designed by MIT astrophysicists are a key component ofa new instrument aboard an orbiting Japanese observatory that willprobe the secrets of such phenomena as exploding stars.
Recently MIT's team was overjoyed -- and relieved -- when theinstrument, the X-ray Imaging Spectrometer (XIS), took its firstpictures, flawlessly capturing the image of an exploded star in theSmall Magellanic Cloud. Only a few weeks earlier, one of the other twoinstruments on the observatory, known as Suzaku, had failed.
For a little while Mark Bautz, leader of the MIT team, also fearedthe worst for XIS. He and colleagues had returned home from Japan,where they had activated their instrument, but were awaiting the finalstep -- the opening of the Japanese-built protective covers -- beforethe cameras could start taking images of the sky.
At 2 a.m. one August morning, Bautz waited in Boston for news ofwhether that step was successful. "I was trading instant messaging withmy Japanese colleagues right up until the commands were sent [to openthe covers], and then all of a sudden they stopped responding," saidthe principal research scientist at MIT's Kavli Institute forAstrophysics and Space Research. "I knew we had only a five-minutewindow, so it wasn't long before I was convinced it hadn't worked."
Half an hour later, the good news finally appeared on his screen."Turns out they were so excited the instrument worked that they forgotto let me know," said Bautz.
Although humans may revel in the bright hues of a rainbow or theflash of a colorful bird, we are blind to a host of other phenomenabecause they radiate light, like X-rays, that our eyes can't detect."It turns out that almost everything you see in the sky emits X-rays aswell, so you can learn a lot about an object by taking X-ray images,"Bautz said.
Enter Suzaku, the latest observatory to explore the X-ray sky. MIThas also been involved in past X-ray expeditions including theHigh-Energy Transient Explorer (HETE-2), the Chandra X-Ray Observatoryand the Advanced Satellite for Cosmology and Astrophysics (ASCA).
The XIS aboard Suzaku is composed of the four cameras developed byMIT plus four telescopes developed at NASA's Goddard Space FlightCenter that focus the sky onto the cameras. The cameras send the imagesback to Earth.
The researchers hope to learn more about such phenomena assupernovas (exploding stars) and clusters of galaxies so massive thatthey trap clouds of hot gas that emit X-rays.
In conjunction with another instrument aboard Suzaku, the XIS willalso help scientists study the emission processes near black holes."There's a nice synergy there because our instrument covers X-rays atvery low energies, while the other instrument goes to very highenergies. Together they'll help us put together the entire X-rayspectrum coming from matter just outside a black hole," Bautz said.
In addition to MIT and NASA, other institutions involved in XIS arethe Institute of Space and Astronomical Sciences of the JapaneseAerospace Exploration Agency, Osaka University and Kyoto University.
Bautz's MIT colleagues on the XIS team are Rick Foster, SteveKissel, Beverly LaMarr, Eric Miller, Gregory Prigozhin, George Ricker,Matthew Smith, James O'Connor and Michael Doucette, all of the KavliInstitute, and Jim Gregory, Barry Burke and Al Pillsbury of Lincoln Lab.
The Suzaku mission is a collaboration between the Japan Aerospace Exploration Agency and NASA.
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