Abstract
view Abstract Citations (95) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The far-ultraviolet continuum of quasars and the universe at Z greater than 4 Netzer, H. Abstract Recent observations of quasars are combined with present theoretical ideas to show a serious energy budget problem in many of these objects. If no reddening is assumed, then the total broad-line flux is a factor of 2 larger than predicted by so-called successful photoionization models. Energy conservation requires a F(nu) varies as /nu to the (-0.4) power/ or flatter ionizing continuum, in conflict with many observations. Alternatively, some unconventional ideas such as extremely thick or extremely dense broad-line clouds, must seriously be considered. Reddening of the broad emission lines helps to solve the problem and bring present day models to better agreement with the observations. The continuum is likely to be reddened or partially obscured as well, and a rising ionizing component should seriously be considered. The far-ultraviolet continuum of quasars is observed to be very steep because of dust, intervening gas, or both. In any event, it would be extremely difficult to observe all wavelengths below approximately 500 A in quasars and possibly in other high-redshift objects. The ultraviolet spectrum of Z approximately 5 objects may never be observed. Publication: The Astrophysical Journal Pub Date: February 1985 DOI: 10.1086/162906 Bibcode: 1985ApJ...289..451N Keywords: Continuous Spectra; Energy Budgets; Far Ultraviolet Radiation; Quasars; Ultraviolet Spectra; Universe; Astronomical Spectroscopy; Cosmology; Emission Spectra; Interstellar Extinction; Interstellar Matter; Line Spectra; Radiant Flux Density; Spectral Line Width; Astrophysics full text sources ADS | data products MAST (1)
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