Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658
Abstract
The co-evolution of a supermassive black hole with its host galaxy through cosmic time is encoded in its spin. At z > 2, supermassive black holes are thought to grow mostly by merger-driven accretion leading to high spin. It is not known, however, whether below z ≈ 1 these black holes continue to grow by coherent accretion or in a chaotic manner, though clear differences are predicted in their spin evolution. An established method of measuring the spin of black holes is through the study of relativistic reflection features from the inner accretion disk. Owing to their greater distances from Earth, there has hitherto been no significant detection of relativistic reflection features in a moderate-redshift quasar. Here we report an analysis of archival X-ray data together with a deep observation of a gravitationally lensed quasar at z = 0.658. The emission originates within three or fewer gravitational radii from the black hole, implying a spin parameter (a measure of how fast the black hole is rotating) of a = 0.87^(+0.08)_(-0.15) at the 3σ confidence level and a > 0.66 at the 5σ level. The high spin found here is indicative of growth by coherent accretion for this black hole, and suggests that black-hole growth at 0.5 ≤ z ≤ 1 occurs principally by coherent rather than chaotic accretion episodes.
Additional Information
© 2014 Macmillan Publishers Limited. Received 28 March 2013; accepted 10 January 2014; Published online 5 March 2014. R.C.R. thanks the Michigan Society of Fellows and NASA for support through the Einstein Fellowship Program, grant number PF1-120087. We thank the ESA XMM-Newton Project Scientist N. Schartel and the XMM-Newton planning team for carrying out the DDT observation. The scientific results reported in this article are based on data obtained from the Chandra Data Archive.Attached Files
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Additional details
- Eprint ID
- 44877
- DOI
- 10.1038/nature13031
- Resolver ID
- CaltechAUTHORS:20140410-162742069
- Michigan Society of Fellows
- PF1-120087
- NASA Einstein Fellowship Program
- Created
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2014-04-11Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field