NASA has selected a science mission that will allow astronomers to explore, for the first time, the hidden details of some of the most extreme and exotic astronomical objects, such as stellar and supermassive black holes, neutron stars and pulsars.
Objects such as black holes can heat surrounding gases to more than a million degrees. The high-energy X-ray radiation from this gas can be polarized – vibrating in a particular direction. The Imaging X-ray Polarimetry Explorer (IXPE) mission will fly three space telescopes with cameras capable of measuring the polarization of these cosmic X-rays, allowing scientists to answer fundamental questions about these turbulent and extreme environments where gravitational, electric and magnetic fields are at their limits. ...
Re: NASA: IXPE to Study Black Holes, Cosmic X-ray Mysteries
<<Imaging X-ray Polarimetry Explorer, IXPE, was launched 9 December 2021 as an international collaboration between NASA and the Italian Space Agency (ASI). IXPE will study exotic astronomical objects and permit mapping the magnetic fields of black holes, neutron stars, pulsars, supernova remnants, magnetars, quasars, and active galactic nuclei. The high-energy X-ray radiation from these objects' surrounding environment can be polarized – vibrating in a particular direction. Studying the polarization of X-rays reveals the physics of these objects and can provide insights into the high-temperature environments where they are created. By obtaining X-ray polarimetry and polarimetric imaging of cosmic sources, IXPE addresses two specific science objectives: to determine the radiation processes and detailed properties of specific cosmic X-ray sources or categories of sources; and to explore general relativistic and quantum effects in extreme environments.
IXPE's payload is a set of three identical imaging X-ray polarimetry systems mounted on a common optical bench and co-aligned with the pointing axis of the spacecraft. Each system operates independently for redundancy, and comprises a 4-meter focal length mirror module assembly that focuses X-rays onto a polarization-sensitive imaging detector developed in Italy. The focal length is achieved using a deployable boom.
X-ray Energy range 2–8 keV
Field of view (FoV) >11′
Angular resolution ≤30″
The Gas Pixel Detectors (GPD) utilize the anisotropy of the emission direction of photoelectrons produced by polarized photons to gauge with high sensitivity the polarization state of X-rays interacting in a gaseous medium. Position-dependent and energy-dependent polarization maps of such synchrotron-emitting sources will reveal the magnetic field structure of the X-ray emitting regions. X-ray polarimetric imaging better indicates the magnetic structure in regions of strong electron acceleration. The system is capable to resolve point sources from surrounding nebular emission or from adjacent point sources.
Technical and science objectives include:
Improve polarization sensitivity by two orders of magnitude
over the X-ray polarimeter aboard the Orbiting Solar Observatory 8
Provide simultaneous spectral, spatial, and temporal measurements
Determine the geometry and the emission mechanism of active galactic nuclei and microquasars
Find the magnetic field configuration in magnetars and determine the magnitude of the field
Find the mechanism for X-ray production in pulsars (both isolated and accreting) and the geometry
Determine how particles are accelerated in pulsar wind nebula
In the image above, the saturation of the magenta color corresponds to the intensity of X-ray light observed by IXPE. It overlays high energy X-ray data, shown in blue, from NASA’s Chandra X-Ray Observatory. Chandra and IXPE, with different kinds of detectors, capture different levels of angular resolution, or sharpness. An additional version of this image is available showing only IXPE data. These images contain IXPE data collected from Jan. 11 to 18.
After Chandra launched in 1999, its first image was also of Cassiopeia A. Chandra’s X-ray imagery revealed, for the first time, that there is a compact object in the center of the supernova remnant, which may be a black hole or neutron star. ...
A key measurement that scientists will make with IXPE is called polarization, a way of looking at how X-ray light is oriented as it travels through space. The polarization of light contains clues to the environment where the light originated. IXPE’s instruments also measure the energy, the time of arrival, and the position in the sky of the X-rays from cosmic sources. ...
With polarization data from Cassiopeia A, IXPE will allow scientists to see, for the first time, how the amount of polarization varies across the supernova remnant, which is about 10 light-years in diameter. Researchers are currently working with the data to create the first-ever X-ray polarization map of the object. This will reveal new clues about how X-rays are produced at Cassiopeia A. ...
