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The Question

(Submitted March 16, 1998)

Who discovered the quasar and when?

The Answer

The discovery of quasars was really spread over time. Quasar is a shortening of "quasi-stellar radio source", and they've also been called quasi-stellar objects or QSOs. In the late 50s, several radio sources were matched with very dim optical objects that looked like stars, but had strange spectra with a lot of ultraviolet excess. One of them, 3C273 had it's position very accurately measured by C. Hazard and co-workers, using lunar occultations. In 1962, M. Schmidt obtained a spectrum of this "star", which showed a redshift of 0.158. This is when QSO was coined, because this was a very distant object that was masquerading as a star, a quasi-stellar object.

This description is paraphrased from a book, "High Energy Astrophysics", by M.S. Longair.

Also, you can see http://heasarc.gsfc.nasa.gov/docs/rosat/gallery/misc_3c273.html

Thanks for your question!

Eric Christian and Maggie Masetti
for Ask an Astrophysicist

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