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Published March 1987 | Published
Journal Article Open

Continuum energy distributions of quasars in the Palomar-Green Survey


Nearly simultaneous observations, from 0.3 to 2.2 µm, of the complete set of quasars found in the Palomar-Green survey are presented, along with 3.7 and 10.1 µm observations of a limited number of the quasars. The majority of the continua at rest frequencies between 10^(13.8) and 10^(15.3) Hz are consistent with fits by two power-law slopes plus a "3000 À bump." The spectral indices representing the lower frequency observations have a median value of -1.4, while those describing the higher frequencies have a median value of -0.2. The transition frequency between these slopes is close to 10^(14.5) Hz in the rest frame; the dispersion around this frequency is about one octave. A significant fraction of the low-redshift quasars show evidence of nebulosity within 5" of the quasar.

Additional Information

© 1987 American Astronomical Society. Received 1986 May 20; accepted 1986 August 25. A long-term project like this has taken effort by many people, especially at Palomar Observatory, and we thank them all, but particularly our night assistants J. Carrasco and G. Tuton. Much of the observing was done together with J. Elias, and we thank him for this and for many conversations. This work was supported by grants from the National Science Foundation.

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Published - 1987ApJS___63__615N.pdf


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