New X-Ray Telescope To Explore Pulsars and Nebulae
23 December 2021
EIRNS—On Dec. 9, the Imaging X-Ray Polarimetry Explorer (IXPE) was launched on a Falcon 9 rocket from NASA’s Kennedy Space Center. This mission will explore some of the inner workings of the universe’s most dynamic and intriguing objects—black holes, neutron stars (pulsars, quasars, and magnetars are all different types of neutron stars), and, for the first time, will be able to image the polarization of x-rays coming out of these objects.
We’re all familiar with polarized sunglasses—what we perceive as “glare” is usually reflected horizontal light. The sunglasses are treated (either chemically or embedded in the lenses) to filter out that horizontal light, and still allow vertical light waves to pass through. If you hold two polarized lenses over each other, you can see how they can block all light as you rotate them in opposite directions; this would be when the polarized direction is at right angles to one another.
This feature comes into play when making astronomical observations—if an object is far away, how can you tell the light is coming from the object itself, or is glare (reflected light) from another source? If the polarized lens is rotated, and the light varies, then we can know that the light is being scattered; if not, then it’s likely that the light is coming directly from a source.
When looking at something like the Crab Nebula, x-ray polarization can show the direction of the magnetic field, and this is the first object which the IXPE will explore. At the center of the nebula is a pulsar, spinning rapidly and flashing like a lighthouse; these are the remains of the star that created the nebula.
Perhaps the most exciting portion of the mission will be when it turns its focus to our galactic center and the black hole at the center of our own Milky Way galaxy. [jgw]