Emission of the Sun in radio wavelengths from centimeters to dekameters, under both quiet and disturbed conditions. Some patterns, known variously as noise storms, bursts, and sweeps, are identified a
s described below. These types of emission are subjectively rated on an importance scale of 1 to 3, 3 representing the most intense.
Type I. A noise storm composed of many short, narrow-band bursts in the meter wavelength range (300-50 MHz), of extremely variable intensity. The storm may last from several hours to several days.
Type ll. Narrow-band emission that begins in the meter range (300 MHz) and sweeps slowly (tens of minutes) toward dekameter wavelengths (10 MHz). Type II emissions occur in loose association with major flares and are indicative of a shock wave moving through the solar atmosphere.
Type III. Narrow-band bursts that sweep rapidly (seconds) from decimeter to dekameter wavelengths (500-0.5 MHz). They often occur in groups and are an occasional feature of complex solar active regions.
Type IV. A smooth continuum of broad-band bursts primarily in the meter range (300-30 MHz). These bursts occur with some major flare events; they begin 10 to 20 minutes after flare maximum and can last for hours.
Type V. Short-duration (a few minutes) continuum noise in the dekameter range usually associated with Type III bursts.
A galaxy that is extremely luminous at radio wavelengths between 10 MHz and 100 GHz. The radio luminosity of a strong radio galaxy (10^37 - 10^39 watts) can be up to a million times greater than the r
adio output of an ordinary galaxy and up to a hundred times greater than the optical luminosity of a galaxy such as the Milky Way. The optical counterparts of radio galaxies are usually an elliptical galaxy. Radio galaxies often exhibit jet structure from a compact nucleus. They typically display two radio lobes that are often approximately aligned with the jets observed in the optical and that may extend for millions of light-years.