An ultra-luminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30

摘要

So far, roughly 40 quasars with redshifts greater than z=6 have beendiscovered. Each quasar contains a black hole with a mass of about one billionsolar masses ($10^9 M_\odot$). The existence of such black holes when theUniverse was less than 1 billion years old presents substantial challenges totheories of the formation and growth of black holes and the coevolution ofblack holes and galaxies. Here we report the discovery of an ultra-luminousquasar, SDSS J010013.02+280225.8, at redshift z=6.30. It has an optical andnear-infrared luminosity a few times greater than those of previously known z>6quasars. On the basis of the deep absorption trough on the blue side of the Ly$\alpha$ emission line in the spectrum, we estimate the proper size of theionized proximity zone associated with the quasar to be 26 million light years,larger than found with other z>6.1 quasars with lower luminosities. We estimate(on the basis of a near-infrared spectrum) that the black hole has a mass of$\sim 1.2 \times 10^{10} M_\odot$, which is consistent with the $1.3 \times10^{10} M_\odot$ derived by assuming an Eddington-limited accretion rate.