Netherlands Research School for Astronomy (NOVA) | 2017 Nov 14
[img3=" Artist's impression of the launching of a jet by a neutron star. Gas, stripped from the normal star in the background, first spirals towards the neutron star before being expelled in a powerful stream of plasma. Credit: NASA/CXC/M.Weiss"]http://www.astronomie.nl/media/medialib ... et_ENG.jpg[/img3][hr][/hr]An international team of astronomers led by the University of Amsterdam (The Netherlands) suspects that neutron stars with a strong magnetic field can still launch so-called jets. Since the 1980s, it was thought that strong magnetic fields inhibit the formation of these plasma streams. But observations with more advanced telescopes indicate jet-like radiation. ...
Jets are energy rich plasma streams that are blown out of black holes or neutron stars at high speed. Jets have been known for decades, but so far no jets have been observed at neutron stars with a strong magnetic field. The prevailing assumption was that strong magnetic fields prevent the formation of jets. Since the eighties, astronomers hardly actively looked for jets at neutron stars with a strong magnetic field.
In 2013, astronomer Nathalie Degenaar (University of Amsterdam, the Netherlands) decided that it was time to observe a few neutron stars with improved telescopes. She asked and got observing time with the Very Large Array (VLA), a radio telescope with 27 dishes in the state of New Mexico (USA). On June 6, 2013, and June 16, 2013, the VLA focused on the binary systems Her X-1 and GX 1+4 for a few dozens of minutes. Both systems consist of a neutron star with a very strong magnetic field and a normal star that orbits around it. Material flows from the normal star to the neutron star. The radio observations were intended to test whether these systems, with such a strong magnetic field, indeed do not launch a jet. ...
The observational data was stocked for some time until the PhD student Jakob van den Eijnden (University of Amsterdam) started to crunch it in the summer of 2017. ... The analysis showed that both neutron stars emit radio radiation and that the intensity of that radiation is comparable to that of jets. The researchers do not claim that there are real jets, because for that claim additional measurements are needed. ...
Discovery of Radio Emission from the Symbiotic X-ray Binary System GX 1+4 - J. van den Eijnden et al
- Monthly Notices of the RAS: Letters (online 13 Nov 2017) DOI: 10.1093/mnrasl/slx181
arXiv.org > astro-ph > arXiv:1711.01958 > 06 Nov 2017
- Monthly Notices of the RAS: Letters (online 13 Nov 2017) DOI: 10.1093/mnrasl/slx180
arXiv.org > astro-ph > arXiv:1711.01971 > 06 Nov 2017