For the first time, scientists have successfully mapped the topography of a pulsar’s two magnetic poles. This was made feasible by an effect of gravity described by Einstein’s theory of general relativity.
Pulsars, or fast rotating neutron stars, are one of the most bizarre objects in the Universe, with a gravitational field second only to black holes. They have the most powerful magnetic fields in the Universe and release radio emission from their magnetic poles. The study outcomes were reported in the Science journal on September 6th, 2019.
“This pulsar, known as PSR J1906+0746, is a member of a binary system with another neutron star. The extreme gravitational environment of the two neutron stars causes spacetime to be distorted. This in turn causes the pulsar to precess, changing the angle we view the radio emission and thus allowing us to map out the emission,” stated Professor Andrew Lyne of The University of Manchester, who used the Lovell telescope at Jodrell Bank Observatory to first ascertain the nature of this system.
This pulsar is expected to precess so far that in 2028 the pulsar will no longer be visible from Earth and we will continue to monitor it with our telescopes including the Lovell Telescope at Jodrell Bank Observatory up to that point to see what more we can learn from this interesting system.
Ben Stappers, Professor of Astrophysics, The University of Manchester
The research group, headed by Gregory Desvignes from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, used observations from the Nançay and Arecibo telescopes.
PSR J1906+0746 is a unique laboratory in which we can simultaneously constrain the radio pulsar emission physics and test Einstein’s theory of general relativity. These results show that the emission beam is not round as might be expected, but elongated.
Gregory Desvignes, Max Planck Institute for Radio Astronomy
The outcome is the most accurate measurement of what is called the geodetic precession effect predicted by the theory of general relativity. In addition, the maps of these emission beams offer vital details related to the population of double neutron stars in the Milky Way galaxy and the predicted gravitational wave detection rate mergers of neutron stars.
“The experiment took us a long time to complete, but was well worth the investment in telescope time,” concluded Michael Kramer, Director of MPIfR and University of Manchester affiliated Professor.