Explore the fascinating world of pulsars in this comprehensive lecture from the "Neutron Stars and Black Holes" summer course. Delve into the remarkable story of the Crab Nebula, understanding its expansion, polarized emission, and the puzzling acceleration of its wisps. Discover the groundbreaking work of scientists like Shklovskii and Pacini, who made crucial predictions about neutron stars. Learn about the serendipitous discovery of pulsars by Jocelyn Bell and the subsequent understanding of their nature as rapidly rotating neutron stars. Examine the unique properties of pulsars, including their periodic pulsations, microstructure of individual pulses, and the phenomenon of "nulling." Gain insights into pulsar electrodynamics, magnetosphere, and the light cylinder concept. Explore various models explaining pulsar radiation, including the Polar Cap Model and pair creation processes. This lecture provides a thorough foundation for understanding pulsars, their emission mechanisms, and their significance in astrophysics.
Neutron Stars and Black Holes - Lecture 6: Pulsars and Their Properties
International Centre for Theoretical Sciences via YouTube
Overview
Syllabus
Time: AM
Neutron Stars and Black Holes Lecture - 6: Pulsars
The remarkable story of the Crab Nebula
Crab Nebula is expanding with a velocity ~ 1500 km per second
Continuous emission is strongly polarized
Expanding wisps near the center of the nebula
Acceleration of the nebula!
Radio emission from the Crab!
A great prediction by Shklovskii
Radio emission from the Crab Nebula is very strongly linearly polarized.
X-Ray emission from the nebula!
The great puzzle!
The great central engine
An extraordinary conjecture by Pacini!
Properties of neutron stars
Oscillating charge will radiate
A Rotating Magnet will radiate
Meanwhile in Cambridge!
Scintillation, or twinkling' of compact radio sources
Jocelyn Bell
An unknown scintillating source
6 August 1967
Periodic pulsations discovered from the same source on 28 November 1967
The great discovery announced!
Micro structure of individual pulses
Coherence of the radio radiation
Brightness temperature limit
Twinkle, twinkle little star
A video made with a TV camera showed that Baade's star pulsed with a period of 33 ms!
The great prediction by Franco Pacini
Neutron Stars as Pulsars
Average pulse profiles are unique to each pulsar. They are like their 'finger print'.
Micro structure of individual pulses
"Nulling" of pulsars
Neutron stars are powerful dynamos!
Pulsar electrodynamics
Magnetosphere of the neutron star
Light Cylinder
Radiation from an accelerated charge
Radiation from a relativistic charge
Radio radiation from pulsars
The Polar Cap Model for pulsars
A hollow cone of radiation
Pulsed emission from the CRAB Pulsar.
Pair creation
Next Lecture - Physical content of the General Theory of Relativity
Q&A
Taught by
International Centre for Theoretical Sciences
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