The broad-band spectra and variability of compact nonthermal sources

QSO Luminosities at λ 1 MM

“…As seen in Table 1 the detection rate at the 3Q flux density level of optically selected quasars increases with redshift while that for radio selection declines. This is also seen for the independently selected radio sample observed by Jones et al [1981). Both radio and optical samples are flux density (apparent magnitude] limited.…”

Extragalactic 1 millimeter sources - Simultaneous observations at centimeter, millimeter, and visual wavelengths

“…Its error is the larger ofthe error in the slope determined from the regression or the propagation of the photometric error in the flux densities. The uncertainty in the correction for galactic extinction does not affect the spectral et al (1978), Jones et al (1981), and Ennis, Neugebauer, and Werner (1982), the number of such 1 mm detections is now 30. We discuss first the spectra defined by our measurements and then their variations since 1977 January.…”

“…The nature of this transition-whether abrupt or gradual, and at what frequency it occurs-can be used to restrict models of the structure and energetics of these sources. Submillimeter or 1-mm observations of nonthermal extragalactic sources have been made by Hildebrand et al (1977), Elias et al (1978), Jones et al (1981), and Ennis, Neugebauer, and Werner (1982). Jones et al report simultaneous radio observations for several sources.…”

Broadband Studies of Compact Sources

“…This ob servational work is supported by theoretical calculations of the appear ance and evolution of compact sources. An analysis of the spectral and variability characteristics of the active sources has been reported elsewhere (Jones et al 1981).A preliminary study of the S4 sources also has been reported (Rudnick and Jones 1982) .The study has shown a strong relationship between the polarization and variability of sources and their spectral shape.If we divide the S4 sources into groups with straight or power spectra (\, e.g., 0954+ 55), simple convex or "humped" spectra (s*\> e.g., 0923+39), and complex spectra e.g., 1641+39), we find that only the complex sources com monly exhibit large amplitude variability on timescales of a few years. The simple convex and straight spectrum sources appear relatively con stant, although they are mostly unresolved at 6cm on the VLA (<0V2) and, therefore, of kiloparsec or smaller dimensions.…”

“…This ob servational work is supported by theoretical calculations of the appear ance and evolution of compact sources. An analysis of the spectral and variability characteristics of the active sources has been reported elsewhere (Jones et al 1981).…”