Although observed already in 1054 by Chinese astronomers, the Crab nebula’s extension in very high energy gamma-rays has remained unknown. Up until now, when an international team of scientists, featuring researchers from Linnaeus University, has succeeded in measuring the extension using the H.E.S.S. telescopes in Namibia.
The Crab nebula is a remnant of a supernova, 6 500 light years away in the Taurus constellation in the Milky Way. It was first observed in 1054 by Chinese astronomers and is one of the most studied celestial objects.
The first measurement of the extension of the Crab nebula in very high energy gamma-rays was presented in the journal Nature Astronomy yesterday by the scientists of the H.E.S.S. telescopes, which are situated in Namibia. This measurement is the result of modern analysis and simulation techniques, enabling a precision unprecedented in gamma-ray astronomy.
“The extension of the Crab nebula strongly depends on the observed energy range. The angular extension of the Crab nebula at gamma-ray energies is about 50 arcseconds, or 0.014 degrees”, explains Yvonne Becherini, associate professor of astrophysics at Linnaeus University and member of the H.E.S.S. collaboration.
Four researchers at Linnaeus University are in the massive list of authors, featuring more than 200 researchers: besides Yvonne Becherini also Tomas Bylund, Michael Punch and Mohanraj Senniappan.
“At Linnaeus University, we have contributed to the internal H.E.S.S. discussions about the analysis and about the findings”, says Yvonne Becherini.
- Read more about the discovery at the website of H.E.S.S..
- The publication: Resolving the Crab pulsar wind nebula at teraelectronvolt energies. H.E.S.S. Collaboration (H. Abdalla et al.). Journal Nature Astronomy 2019.
- The Astroparticle Physics research group's web page.
The X-ray emission from the Crab Nebula as imaged with the Chandra telescope is shown in the centre in yellow/orange (image courtesy of M. C. Weisskopf and J. J. Kolodziejczak). The blue points denote the reconstructed directions of gamma-ray events as measured with the H.E.S.S. telescopes. The white circle shows the corresponding extension of the Crab Nebula as derived by the H.E.S.S. scientists.