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Are the Highest-Redshift Quasars Magnified by Intervening Gravitational Lenses? (2002)
BibTeX
@MISC{Stuart02arethe,
author = {J. Stuart and B. Wyithe and Abraham Loeb},
title = {Are the Highest-Redshift Quasars Magnified by Intervening Gravitational Lenses?},
year = {2002}
}
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Abstract
The Sloan digital sky survey (SDSS) has recently discovered exceptionally bright quasars1 with redshifts of up to 6.28. Naively, these observations imply the existence of black holes with masses in excess of a few billion solar masses only a billion years after the big bang. Moreover the inferred luminosities of these bright quasars are systematically higher than expected from the survey selection criteria. Here we explain these puzzling results by the inevitable phenomenon of gravitational lensing. We find that up to a third of the SDSS quasars at z ∼ 6 are likely to have their intrinsic flux magnified by a factor ∼> 10 due to lensing by intervening galaxies. The z ∼ 6 quasars appear to be as bright as 3C273, the brightest quasar in the local universe. Even if these accreting black holes shine near their maximum (Eddington) luminosity, their observed fluxes require the assembly of a mass ∼> 3×10 9M ⊙ in a relativistic potential well when the age of the universe was only 5 − 10 % of its current value, and so they challenge models for early structure formation2,3. The prominence of supermassive black holes in the early universe could have important implications for the re-ionization of
Keyphrases
intervening gravitational lens highest-redshift quasar magnified black hole current value survey selection criterion early universe relativistic potential well intrinsic flux bright quasars1 solar mass sloan digital sky survey gravitational lensing local universe early structure formation2 inevitable phenomenon big bang supermassive black hole bright quasar observed flux sd quasar important implication inferred luminosity
