Astronomy   View all facts   Glossary   Help

physical object > natural object > celestial body > radio source

radio source
subject			fact

radio source	has wavelength radio
	is a part of celestial sphere
	has catalog radio source catalog
	has definition A source of extraterrestrial radio radiation. The strongest known is Cassiopeia A, followed by Cyg A and the Crab Nebula (Tau A) (the capital letters following the name of a constellation refer to the radio sources of the constellation, A being the strongest source). Radio sources are divided into two main categories: Class I, those associated with our Galaxy (which is a weak radio source), and Class II, extragalactic sources. Most radio sources are galaxies, supernova remnants, or H II regions.
	is a kind of celestial body
celestial body	has spectra
physical object	has location or center of gravity
	has angular momentum
	has mass
	has velocity
	has momentum
	has temperature
	has volume
	has extent
	has material

Kinds of radio source :

• Cassiopeia A (8 facts) (3C 461, 3U 2321+58) - A radio source in Cassiopeia, the strongest extrasolar source in the sky, believed to be the remnant of a Type II supernova whose light reached Earth about 1667. Optically it is a faint nebula. It has a mass of a few solar masses. It is also an extended source of soft X-rays.
• Centaurus A (7 facts) (3U 1322-42, NGC 5128) - A strong radio source. Optically, it is an elliptical galaxy with a dark obscuring lane. It is the nearest known violent galaxy.
• Lupus Loop (3 facts) - A radio source, a large broken shell 4°.5 in diameter, identified as a prehistoric supernova remnant.
• North Polar Spur (4 facts) - A radio continuum feature extending from the galactic plane to the vicinity of the North Galactic Pole. It is believed to be a supernova remnant. It is also an X-ray source.
• Orion A (3 facts) - A radio continuum feature (an H II region) centered on the Trapezium, and excited by θ¹ Ori C. The Orion A molecular cloud, which lies beyond it, is a rich source of molecules CO, OH, HCN, and probably NO, HCO, and H₂CO have been observed.
• Orion B (4 facts) (NGC 2024) - A radio continuum source.
• radio galaxy (19 kinds, 72 facts) - A galaxy that is extremely luminous at radio wavelengths. A radio galaxy is usually a giant elliptical - the largest galaxy in a cluster - and is a strong emitter of synchrotron radiation. M87 and M82 are examples.
• radio lobes (2 facts) - Extended regions of diffuse radio emission, often dumbbell shaped, that surround a radio galaxy.
• Sagittarius A (5 facts) - A radio source (the galactic center). (Sgr A West is a thermal source; Sgr A East is a nonthermal source.), The very center of the Milky Way, Sagittarius A^* is a strong source of radio waves and probably a massive black hole.
• Sagittarius B2 (4 facts) - A massive (3 × 10⁶ M_sun), dense (up to 10⁸ particles per cm³) H II region and molecular cloud complex - the richest molecular source in the Galaxy. It is in the galactic plane, near the galactic center.
• supernova remnant (7 kinds, 50 facts) (SNR) - The expanding shell of gas ejected at high speed by a supernova explosion, observed as an expanding diffuse gaseous nebula, often with a shell-like structure., A gaseous nebula, the expanding shell ejected by a supernova, and deriving its energy (at least in some cases) from the conversion by the remanent neutron star of its rotational energy into a stream of high-energy particles being continually accelerated in the SNR. About 100 SNRs are known in our Galaxy. Supernova remnants are usually powerful radio sources.
• W3 (4 facts) - A dense cloud of gas in the Perseus arm.
• W49 (3 facts) - A radio source (a giant H II region). It is the most powerful thermal radio source known in our Galaxy.