Supermassive Black Holes in the Early Universe

Abstract: The recent discovery of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.3 has exacerbated the time compression problem implied by the appearance of supermassive black holes only ~900 Myr after the big bang, and only ~500 Myr beyond the formation of Pop II and III stars. Aside from heralding the onset of cosmic reionization, these first and second generation stars could have reasonably produced the ~5-20 solar-mass seeds that eventually grew into z~6-7 quasars. But this process would have taken ~900 Myr, a timeline that appears to be at odds with the predictions of LCDM without an anomalously high accretion rate, or some exotic creation of ~10^5 solar-mass seeds. There is no evidence of either of these happening in the local universe. In this paper, we show that a much simpler, more elegant solution to the supermassive black hole anomaly is instead to view this process using the age-redshift relation predicted by the R_h=ct Universe, an FRW cosmology with zero active mass. In this context, cosmic reionization lasted from t~883 Myr to ~2 Gyr (z~15 to z~6), so ~5-20 solar-mass black hole seeds formed shortly after reionization had begun, would have evolved into ~10^10 solar-mass quasars by z~6-7 simply via the standard Eddington-limited accretion rate. The consistency of these observations with the age-redshift relationship predicted by R_h=ct supports the existence of dark energy; but not in the form of a cosmological constant.