Pulsars as a tool for test of strong gravity
Jérôme PÉTRI
Observatoire Astronomique de Strasbourg
Course
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Abstract
Although they have been discovered more than 40 years ago, pulsars remain enigmatic compact objects. This lecture summarizes our current knowledges about pulsars from an observational point of view as well as from a theoretical one. In a first part, we remind some basic observational facts in order to fix the orders of magnitude (neutron star radius, rotation rate, magnetic field, spin down luminosity) and give some properties of their spectra, from the radio wavelengths to X-rays and gamma-rays. In a second part, we review some models for pulsar magnetospheres which predict the launch of a relativistic wind. We will give an overview of the whole system, from the neutron star surface up to the surrounding nebula. In a third part, we will show that pulsars help to map electrons in the Milky Way as well as the galactic magnetic field. The high precision pulsar timing allowed the detection of the first extrasolar planet around a pulsar and indirectly demonstrated the existence of gravitational waves. In
a last part, we show how to constrain theories of relativistic
gravitation from the observation of neutron stars in binary systems
containing one or even two pulsars. We will discuss in more details the
exceptional case of the double pulsar PSR~J0737-3039 for which the
masses of the two neutron stars have been measured with great accuracy.
These observations agree with the predictions of general relativity.
Bibliography
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