Astronomical radio source

As a radio source is an astronomical object is known in radio astronomy, which emits significant radio waves. The strongest astronomical radio sources are sun, exploding stars, quasars and radio galaxies known.

The first observed in the night sky radio source was the diffuse radio emission of the Milky Way (1931 /32). Their discoverer, Karl Jansky was thus the founder of radio astronomy that developed in 1950 to a rapidly growing branch of astronomy.

Causes astronomical radio emission

Such celestial bodies are also referred to as radio loud - as opposed to radio quiet objects that are (almost ) do not emit radio waves. Your radio emission may be caused by the following physical mechanisms:

  • Thermal radiation: Due to its intrinsic temperature emits a body in the cosmos heat radiation.
  • Synchrotron Radiation: Cosmic nebulae are often located in the state of a plasma. At the same time a magnetic field present, the electrons (and ions ) are forced along helical paths around the lines of force in the tangential direction, and radiation, therefore, continual from synchrotron radiation. The intensity of radio waves decreases as frequency.
  • Gas clouds: If radio sources irradiate gas clouds absorb radio waves of certain wavelengths corresponding to the spectrum of the gas and isotropic radiated again. In " see-through", that is, if a radio source is behind the gas cloud observed absorption lines, emission lines in all other directions, see spectroscopy. Important wavelengths are: the hydrogen line with a wavelength of 21.1 cm ( 1420.40575177 MHz)
  • The CO - line with a wavelength of 0.260 cm ( 115,271.2 MHz)
  • The OH lines at wavelengths of 92 cm, 18.0 cm and 6.29 cm ( 327 MHz, 1665.402 / 1667.357 MHz and 4765 MHz)
  • H2O - line with a wavelength of 1.35 cm ( 22.23508 GHz)

Classes of radio sources

  • The sun: In the sunspot minimum, the quiet sun radiates approximately like a black body. Certain wavelength ranges are amplified emitted when the sun is active. In addition, prominences are very good also observable in the radio range
  • Moon and planets: Send All planets from black-body radiation, see eg Jupiter bursts.
  • Supernova remnants and pulsars in our galaxy and in other galaxies
  • Radio galaxies and " active galactic nuclei "
  • Quasars ( portmanteau for quasi- stellar objects )
Field line Isotropy Hydroxyl radical Population inversion Magnetosphere of Jupiter Radio galaxy Cygnus X-1 Cassiopeia A
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