It will provide a Universe-wide assessment on these traits

Aug 5, 2009 10:15 GMT  ·  By
GEMS will detect polarized X-rays from supernova remnants, neutron stars and black holes. Polarized X-rays carry information about the structure of cosmic sources that is not available in any other way
   GEMS will detect polarized X-rays from supernova remnants, neutron stars and black holes. Polarized X-rays carry information about the structure of cosmic sources that is not available in any other way

The NASA-operated Goddard Space Flight Center, in Greenbelt, Maryland, is currently buzzing with excitement, as engineers are working around the clock to complete a new satellite. Dubbed the Gravity and Extreme Magnetism Small Explorer (GEMS), the instrument will systematically measure the polarization of cosmic X-ray sources throughout the Universe, and will complete the first such map ever. Astronomers hope that the new observatory will open up a new and revolutionary window towards understanding the Cosmos.

“To date, astronomers have measured X-ray polarization from only a single object outside the solar system – the famous Crab Nebula, the luminous cloud that marks the site of an exploded star. We expect that GEMS will detect dozens of sources and really open up this new frontier,” Goddard Astrophysicist Jean Swank, the principal investigator for the GEMS mission, says of the satellite. All science operations, science data processing and system engineering will be conducted at Goddard, which is also in charge of providing the X-ray mirrors and polarimeter instruments for the probe.

The main reason why source polarization was selected to be the main objective of the new mission is the fact that it can hint to the presence of a black hole at unknown locations. When electromagnetic radiation, such as visible light, radio waves, and X-rays moves past a black hole, not only is its direction changed, but also its polarization. If GEMS detects a shift in this trait at a seemingly empty point in space, then it could very well mean that a black hole inhabits that place.

“Thanks to these effects, GEMS can probe spatial scales far smaller than any telescope can possibly image,” Swank adds. Additionally, the researcher reveals, certain information about the origin and traits of cosmic X-ray sources is only carried in electromagnetic radiation polarization, and is not available to other types of observation instruments. “GEMS will be about 100 times more sensitive to polarization than any previous X-ray observatory, so we're anticipating many new discoveries,” Goddard Assistant Director for Flight Projects and GEMS Project Manager Sandra Cauffman shares.

The University of Iowa will assist with instrument calibration, and students there will develop an experiment that could become part of the mission. Other GEMS collaborators include the Massachusetts Institute of Technology, Cambridge, Mass.; the Johns Hopkins University, Baltimore, Md.; the Cornell University, Ithaca, N.Y.; the Rice University, Houston, Texas; the North Carolina State University, Raleigh; the Washington University, St. Louis, Mo. and the University of Oulu in Finland.

Further details of the new GEMS satellite can be viewed here.