An article to be published in “The Astrophysical Journal” reports a study on Tycho supernova remnants which offers new information on the geometry of its magnetic fields. A team of astronomers led by Riccardo Ferrazzoli of the Italian National Institute of Astrophysics used observations conducted with the IXPE space telescope to examine the polarized X-rays emitted by these supernova remnants. This allowed new clues to be found about the conditions in the shock waves generated by the supernova that accelerate particles to speeds close to the speed of light.
Launched on December 9, 2021, the IXPE (Imaging X-ray Polarimetry Explorer) space telescope is a collaborative mission between NASA and the Italian Space Agency. IXPE is equipped with three highly advanced telescopes that are equipped with polarization detectors, a property of electromagnetic emissions generated by their sources. Consequently, the ability to measure the polarization of observed X-rays offers clues about the environment in which they were generated. The main purpose is to measure the polarization of cosmic X-rays but it’s very useful for other types of studies of polarized emissions as well such as those from supernova remnants.
Tycho supernova remnants continue to be studied more than 450 years after its light was first seen from Earth. Riccardo Ferrazzoli explained that the importance of these remains goes beyond scientific interest because it’s one of the so-called historical supernovae whose observation is recorded in historical documents with a social and even artistic impact.
The study of the polarization of the light coming from the Tycho supernova remnants allows an understanding of what happens inside them. An article published in “The Astrophysical Journal Letters” in May 2016 offered some clues about the supernova and its consequences but there was still much to discover about the ongoing processes. Observing details in the midst of the various types of materials that form those remains is difficult, therefore the information obtained indirectly thanks to the observations of the polarization conducted with the IXPE space telescope is precious.
The result is the mapping of the shape of the magnetic fields of Tycho supernova remnants in unprecedented detail. This helps to understand how the shock waves generated by the supernova accelerated particles to speeds close to the speed of light.
This mapping also showed similarities and differences between Tycho supernova remnants and Cassiopeia A supernova remnants, a previous object of study with the IXPE Space Telescope. In Tycho’s case, the X-ray polarization is much higher than in Cassiopeia A, suggesting that its magnetic field may be more orderly and less turbulent.
The diversity between the two supernova remnants studied so far with the IXPE space telescope is of interest to researchers. Laura Di Gesu, a researcher at the Italian Space Agency and one of the authors of the article, commented that this repays her and her colleagues for the investment made in their work to make IXPE the reality it is today.
Indeed, the results that the IXPE space telescope is showing in the initial phase of its scientific mission confirm the importance of X-ray polarimetry. In the case of supernova remnants, the mapping of magnetic fields will add new information on the physical conditions existing in star explosions.
Supernovae have fascinated humans for who knows how many centuries and Tycho’s is one of the best-known. In general, supernova remnants can be the subject not only of spectacular photos but scatter elements created during those catastrophic events in space, including those indispensable to life forms similar to those on Earth. Those elements may become part of some planet just like those generated by very ancient supernovae that ended up on Earth.