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Quasar 3C273
Chandra X-ray of 3C273
Credit: NASA/CXC/
SAO/H. Marshall et al.
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Quasars look like any normal star through an optical telescope. It wasn’t
until the 1950’s, when radio astronomy was first developed, that
astronomers realized these extragalactic objects are emitting massive amounts of
radio energy. This important discovery was named a quasar, short for
“Quasi-stellar radio source”. By waiting for known radio sources to
pass behind the moon, optical and radio data could be combined to give
astronomers the precise location of quasars in the sky.
Quasars are among the most distant, energetic objects ever observed. Even though
individual quasars are brighter than hundreds of galaxies put together, many are
smaller than the size of our own solar system.
What is 3C273?
Radio astronomers use a system of numbers to name objects in the sky. 3C273 was
named in the 3rd Cambridge catalog as the 273rd radio source identified. 3C273,
along with 3C48, were the first quasars to be identified. These objects had
bizarre spectra unlike any ever studied before. In 1963
astronomers Maarten Schmidt (3C273) and Jesse Greenstein and Thomas Matthews
(3C48) noticed that the spectrum made sense if it was simply an extremely large
redshift. In other words, 3C273 was moving away from us at
an incredible one-tenth the speed of light.
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