Fifty Years of Quasars by Mauro D'Onofrio download in pdf, ePub, iPad
He popped the plate into the viewer, and it suddenly dawned on him that three of his lines, plus one in the infrared that Associate Professor of Astronomy J. As the gas spirals into the black hole, it releases energy in the form of radiation and heat, surrounding the black hole with a brilliant glow. But many of the specifics of this picture are up for debate. In his excitement, Schmidt began pacing the hallway, where he buttonholed Professor of Astrophysics Jesse Greenstein.
And research aligned with his initial thoughts. Every chemical element, when sufficiently heated, emits visible light at a few specific, well-known wavelengths. And even the gaseous accretion disk supposed to feed black holes has its share of theoretical problems.
The more distant a galaxy is, the more its light gets stretched, en route to us, by the relentless expansion of the universe. Beverley Oke had found using the inch telescope on Mount Wilson, formed a series whose spacing and intensity decreased uniformly from red to blue.
Quasars, as any other object in the universe, will take time to understand. In those days, a radio telescope recorded a wavy line on a roll of chart paper. Sirius, Arcturus, Vega, Antares, and the like.
As in visible red, not infrared. The second, by Schmidt, announced the redshift. Measuring how much a given line has been shifted toward redder, longer wavelengths tells you how long the light's been traveling and thus how far it has come. Picking out the radio source from the myriad of small blots on a photographic plate requires extremely accurate coordinates. But X-rays are a different story.
The holders, in turn, were packed in a light-tight box about the size of a cigar box for their journey to and from the spectrograph. But every now and then the source would be a starlike pinprick of light. Optical and ultraviolet spectra give a wealth of information about the accretion disk that feeds the black hole and the dusty wind that might arise from that disk. As a favorite professor of mine used to say, X-ray photons are often so few in number, you can name them. The faintest stars visible to the naked eye are sixth magnitude.
Larger, purpose-built dishes also had sprung up in England, Australia, and North America. In order to figure out what the source was, you had to train an optical telescope on the same point in the sky. When six o'clock rolled around and no other solution had presented itself, they decided to call it a day. But as seen through a really large telescope, such as Caltech's inch Hale Telescope atop Palomar Mountain, the sky is a very crowded place. Some feeding supermassive black hole shoot out jets at nearly the speed of light, shown here in this artistic depiction, but astronomers still don't even know what particles make up these jets.
When this plate was developed, it showed four nice, fat lines that, once again, didn't match anything. Matthews was using interferometry, triangulating the source's position from the very slight difference in the arrival times of its wave peaks at his two radio dishes.
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