Chapter 2
Observations of Radio and X-ray Pulsars
From Sect. 1.3.2, it is known that the pulsars radiate the signals in the radio, infrared,
visible, ultraviolet, X-ray and gamma-ray bands of the electromagnetic spectrum,
but the atmosphere of the Earth only opens “two observable windows” for human
beings: one is radio window and another is optical window. In other words, only can
the radiation signals in the radio and visible bands freely reach the ground, while
those in the infrared, ultraviolet, X-ray and gamma-ray bands are obstructed outside
the atmosphere and observed only by using the detection devices carried with the
spacecrafts in outer space. Currently, most of the catalogued pulsars radiated the
signals only in the radio and X-ray bands, and a few of the pulsars in the infrared,
visible, ultraviolet and gamma-ray bands. In the applications of constructing the
pulsar timing system and space navigation, the pulsars emitting the radio and X-ray
signals at the same time are usually selected as the catalogued objects in the database.
Therefore, it has important engineering application value and scientific research
significance to intensively discuss the observations of the radio and X-ray pulsars.
In this chapter, the contents related to the radio and X-ray pulsars are introduced
from two aspects: one is to describe the technical developments and principles, and
another is to discuss the observation approaches and devices.
2.1 A Brief History of Radio Astronomy
Since ancient times, people have seen stars in the visible-light window. Although the
radio window is always opened, nobody knows all about it and the radio radiations
from celestial bodies. In 1865, a Scottish physicist and mathematician James Clerk
Maxwell (1831−1897) published a classic paper, “A Dynamical Theory of the Electromagnetic Field”, in which it is demonstrated that the electric and magnetic fields
travel through space as waves moving at the velocity of light. In 1873, Maxwell
published his classic work, A Treatise on Electricity and Magnetism, in which a
set of partial differential equations to describe the characteristics of electromagnetic
© National Defense Industry Press and Springer Nature Singapore Pte Ltd. 2021
P. Shuai, Understanding Pulsars and Space Navigations, Navigation: Science
and Technology 11, https://doi.org/10.1007/978-981-16-1067-7_2
41
Observations of Radio and X-ray Pulsars
From Sect. 1.3.2, it is known that the pulsars radiate the signals in the radio, infrared,
visible, ultraviolet, X-ray and gamma-ray bands of the electromagnetic spectrum,
but the atmosphere of the Earth only opens “two observable windows” for human
beings: one is radio window and another is optical window. In other words, only can
the radiation signals in the radio and visible bands freely reach the ground, while
those in the infrared, ultraviolet, X-ray and gamma-ray bands are obstructed outside
the atmosphere and observed only by using the detection devices carried with the
spacecrafts in outer space. Currently, most of the catalogued pulsars radiated the
signals only in the radio and X-ray bands, and a few of the pulsars in the infrared,
visible, ultraviolet and gamma-ray bands. In the applications of constructing the
pulsar timing system and space navigation, the pulsars emitting the radio and X-ray
signals at the same time are usually selected as the catalogued objects in the database.
Therefore, it has important engineering application value and scientific research
significance to intensively discuss the observations of the radio and X-ray pulsars.
In this chapter, the contents related to the radio and X-ray pulsars are introduced
from two aspects: one is to describe the technical developments and principles, and
another is to discuss the observation approaches and devices.
2.1 A Brief History of Radio Astronomy
Since ancient times, people have seen stars in the visible-light window. Although the
radio window is always opened, nobody knows all about it and the radio radiations
from celestial bodies. In 1865, a Scottish physicist and mathematician James Clerk
Maxwell (1831−1897) published a classic paper, “A Dynamical Theory of the Electromagnetic Field”, in which it is demonstrated that the electric and magnetic fields
travel through space as waves moving at the velocity of light. In 1873, Maxwell
published his classic work, A Treatise on Electricity and Magnetism, in which a
set of partial differential equations to describe the characteristics of electromagnetic
© National Defense Industry Press and Springer Nature Singapore Pte Ltd. 2021
P. Shuai, Understanding Pulsars and Space Navigations, Navigation: Science
and Technology 11, https://doi.org/10.1007/978-981-16-1067-7_2
41