Gravitational collapse

MAY 01, 1964

Quasi‐stellar radio sources, a subject of intense interest since their discovery in 1960, were the central theme of the International Symposium on Gravitational Collapse and Other Topics in Relativistic Astrophysics, held in Dallas, December 16 to 18, 1963. During the meeting, at the request of L. V. Berkner, it was renamed the John F. Kennedy Memorial Symposium. The author of this review of the discussions is a physicist at NASA’s Goddard Institute for Space Studies and an adjunct assistant professor at Columbia University.

DOI: 10.1063/1.3051610

Hong‐Yee Chiu

With the exception of a few supernova remnants which are in our galaxy, most cosmic radio sources are “radio galaxies”. Although flare stars do emit radio waves occasionally, no ordinary stars with strong, steady radio emission have been found. The typical optical power of stars is from $10^{30} ergs / \sec$ (white dwarfs) to $10^{38} ergs / \sec$ (super giants). For comparison, the optical power of the sun is ${4×10}^{33} ergs / \sec .$ The typical radio power of supernova remnants is around $10^{36} ergs / \sec .$ For a giant galaxy (containing approximately $10^{11} {−10}^{12}$ stars with a total mass of around $10^{11} ⊙,$ where $⊙ = solar$ ${mass = 2×10}^{33} g$ ), the optical power is around $10^{44} ergs / \sec .$ Radio emission from normal galaxies is generally weaker, the power ranging from $10^{37} {−10}^{39} ergs / \sec .$ For certain peculiar galaxies, the so‐called “radio galaxies,” the radio emission rate ranges from $10^{41} {−10}^{44.5} ergs / \sec .$

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