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



So far, roughly 40 quasars with redshifts greater than z = 6 have been discovered1,2,3,4,5,6,7,8. Each quasar contains a black hole with a mass of about one billion solar masses (109 )2,6,7,9,10,11,12,13. The existence of such black holes when the Universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the coevolution of black holes and galaxies14. Here we report the discovery of an ultraluminous quasar, SDSS J010013.02+280225.8, at redshift z = 6.30. It has an optical and near-infrared luminosity a few times greater than those of previously known z > 6 quasars. On the basis of the deep absorption trough15 on the blue side of the Lyman-α emission line in the spectrum, we estimate the proper size of the ionized proximity zone associated with the quasar to be about 26 million light years, larger than found with other z > 6.1 quasars with lower luminosities16. We estimate (on the basis of a near-infrared spectrum) that the black hole has a mass of 1.2 × 1010 , which is consistent with the 1.3 × 1010 derived by assuming an Eddington-limited accretion rate.

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Figure 1: The optical spectra of J0100+2802.
Figure 2: Transmission in absorption troughs and the proximity zone for J0100+2802.
Figure 3: The combined optical/near-infrared spectrum of J0100+2802 and the fitting of the Mg ii line.
Figure 4: Distribution of quasar bolometric luminosities, Lbol, and black-hole masses, MBH, estimated from the Mg ii lines.

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X.-B.W. thanks the NSFC (grant nos 11033001 and 11373008), the Strategic Priority Research Program ‘The Emergence of Cosmological Structures’ of the Chinese Academy of Sciences (grant no. XDB09000000), and the National Key Basic Research Program of China (grant no. 2014CB845700) for support. X.F., R.W. and I.D.M. thank the US NSF (grant nos AST 08-06861 and AST 11-07682) for support. R.W. thanks the NSFC (grant no. 11443002) for support. We acknowledge the support of the staff of the Lijiang 2.4-m telescope. Funding for the telescope was provided by the Chinese Academy of Sciences and the People’s Government of Yunnan Province. This research uses data obtained through the Telescope Access Program (TAP), which has been funded by the Strategic Priority Research Program ‘The Emergence of Cosmological Structures’ (grant no. XDB09000000), National Astronomical Observatories, Chinese Academy of Sciences, and the Special Fund for Astronomy from the Ministry of Finance of China. We thank D. Osip for help with Magellan/FIRE spectroscopy, and Y.-L. Ai, L. C. Ho, Y. Shen and J.-G. Wang for suggestions about data analyses. We acknowledge the use of SDSS, 2MASS and WISE data, and of the MMT, LBT, Gemini and Magellan telescopes; detailed acknowledgments of these facilities can be found in Supplementary Information.

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X.-B.W., F.W. and X.F. planned the study, and wrote the draft version of the paper. All other co-authors contributed extensively and equally to the observations, data analyses and writing of the manuscript.

Corresponding author

Correspondence to Xue-Bing Wu.

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The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Images of J0100+2802 in SDSS, 2MASS and WISE bands.

J0100+2802 is undetected in SDSS u,g,r bands (top row) but is relatively bright in other bands (lower three rows). It is consistent with a point source in the bands with high signal-to-noise detections. The size is 1′ × 1′ for all images. The green circle represents an angular size of 10″ in each image.

Extended Data Figure 2 The LBT K-band image of J0100+2802.

The size is 10″ × 10″. The horizontal and vertical axes denote the offsets in right ascension (ΔRA) and in declination (ΔDec.). The image, with seeing of 0.4″, shows a morphology fully consistent with a point source.

Extended Data Figure 3 The rest-frame spectral energy distributions of J0100+2802, J1148+5251 and ULAS J1120+0641.

The redshifts of these three quasars are 6.30, 6.42 and 7.085, respectively. The luminosity of J0100+2802 in the ultraviolet/optical bands is about four times higher than that of J1148+5251, and seven times higher than that of ULAS J1120+0641. The photometric data are from literature for J1148+5251 and J1120+0641. The error bars show the 1σ standard deviation.

Extended Data Figure 4 The major absorption features identified from optical and near-infrared spectroscopy of J0100+2802.

Most of them are from Mg ii, C iv and Fe ii. The labels from A to H correspond to the redshifts of absorption materials at 6.14, 6.11, 5.32, 5.11, 4.52, 4.22, 3.34 and 2.33, respectively. Studies of intervening and associated absorption systems will be discussed elsewhere.

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Wu, XB., Wang, F., Fan, X. et al. An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30. Nature 518, 512–515 (2015).

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