NASA captures detailed look of Crab Nebula, more secrets revealed
New Delhi : Scientists have utilized NASA's Imaging X-ray Polarimetry Explorer (IXPE) to generate a comprehensive and intricate map of the Crab Nebula, shedding new light on the inner workings of its donut-shaped magnetic field.
Situated approximately 6,500 light-years away from Earth, the Crab Nebula is a extensively examined astronomical phenomenon resulting from a supernova event recorded in 1054. The explosion of a massive star gave rise to the Crab Pulsar, a dense object emitting gases, shock waves, magnetic fields, and high-energy light and particles, creating a peculiar and enigmatic environment that is still not fully understood.
"The Crab Nebula has been extensively studied as one of the most prominent high-energy astrophysical objects in the sky. Therefore, it is particularly thrilling that the utilization of IXPE's polarized lenses has enabled us to gain new insights into this system," stated Michela Negro, a research scientist at NASA's Goddard Space Flight Center affiliated with the University of Maryland, Baltimore, and a co-author of the study.
Although the magnetic field of the Crab Nebula shares similarities with that of the Vela Pulsar Wind Nebula, recent findings have revealed unexpected characteristics. Scientists were surprised to discover that the magnetic field turbulence in the Crab Nebula is more irregular and uneven than anticipated, displaying patchy and asymmetrical patterns.
Back in the 1970s, Weisskopf, who is currently an emeritus astronomer at NASA's Marshall Space Flight Center in Huntsville, Alabama, and his colleagues conducted X-ray polarization measurements of the Crab Nebula in order to gain insights into its extreme environment. Their findings indicated that the Crab Nebula exhibits an average polarization of approximately 20%.
The measurements of polarization obtained by IXPE for the entire Crab Nebula were consistent with those previously conducted by Weisskopf and his team. However, the advanced capabilities of IXPE allowed for a more precise determination of polarization angles and enabled the study of polarization variations across the entire nebula. Interestingly, the IXPE data revealed that the outer regions of the nebula exhibited significantly higher levels of polarization compared to areas closer to the pulsar where polarization was lower.
These findings suggest that the X-rays in the Crab Nebula predominantly originate from the outer magnetic field region, commonly referred to as the "wind" region. However, the exact location and mechanism of this process are still unknown and require further investigation.