Abstract
Since the 1995 discovery of the broad iron K-line emission from the Seyfert galaxy MCG–6-30-15 (ref. 1), broad iron K lines have been found in emission from several other Seyfert galaxies2, from accreting stellar-mass black holes3 and even from accreting neutron stars4. The iron K line is prominent in the reflection spectrum5,6 created by the hard-X-ray continuum irradiating dense accreting matter. Relativistic distortion7 of the line makes it sensitive to the strong gravity and spin of the black hole8. The accompanying iron L-line emission should be detectable when the iron abundance is high. Here we report the presence of both iron K and iron L emission in the spectrum of the narrow-line Seyfert 1 galaxy9 1H 0707-495. The bright iron L emission has enabled us to detect a reverberation lag of about 30 s between the direct X-ray continuum and its reflection from matter falling into the black hole. The observed reverberation timescale is comparable to the light-crossing time of the innermost radii around a supermassive black hole. The combination of spectral and timing data on 1H 0707-495 provides strong evidence that we are witnessing emission from matter within a gravitational radius, or a fraction of a light minute, from the event horizon of a rapidly spinning, massive black hole.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Tanaka, Y. et al. Gravitationally redshifted emission implying an accretion disk and massive black hole in the active galaxy MCG–6–30–15. Nature 375, 659–661 (1995)
Nandra, K. et al. An XMM-Newton survey of broad iron lines in Seyfert galaxies. Mon. Not. R. Astron. Soc. 382, 194–228 (2008)
Miller, J. M. Relativistic X-Ray lines from the inner accretion disks around black holes. Annu. Rev. Astron. Astrophys. 45, 441–479 (2007)
Cackett, E. M. et al. Relativistic iron emission lines in neutron star low-mass X-ray binaries as probes of neutron star radii. Astrophys. J. 674, 415–420 (2008)
Guilbert, P. W. & Rees, M. J. ‘Cold’ material in non-thermal sources. Mon. Not. R. Astron. Soc. 233, 475–484 (1988)
Ross, R. R. & Fabian, A. C. The effects of photoionization on X-ray reflection spectra in active galactic nuclei. Mon. Not. R. Astron. Soc. 261, 74–82 (1993)
Fabian, A. C. et al. X-ray fluorescence from the inner disc in Cygnus X-1. Mon. Not. R. Astron. Soc. 238, 729–736 (1989)
Brenneman, L. W. & Reynolds, C. S. Constraining black hole spin via X-ray spectroscopy. Astrophys. J. 652, 1028–1043 (2006)
Osterbrock, D. E. & Pogge, R. W. The spectra of narrow-line Seyfert 1 galaxies. Astrophys. J. 297, 166–176 (1985)
Boller, Th et al. XMM-Newton discovery of a sharp spectral feature at 7 keV in the narrow-line Seyfert 1 galaxy 1H 0707–49. Mon. Not. R. Astron. Soc. 329, L1–L5 (2002)
Fabian, A. C. et al. X-ray reflection in the narrow-line Seyfert 1 galaxy 1H 0707–495. Mon. Not. R. Astron. Soc. 353, 1071–1077 (2004)
Gallo, L. C. et al. Long-term spectral changes in the partial-covering candidate narrow-line Seyfert 1 galaxy 1H 0707–495. Mon. Not. R. Astron. Soc. 353, 1064–1070 (2004)
Tanaka, Y. et al. Partial covering interpretation of the X-ray spectrum of the NLS1 1H 0707–495. Publ. Astron. Soc. Jpn 56, L9–L13 (2004)
Laor, A. Line profiles from a disk around a rotating black hole. Astrophys. J. 376, 90–94 (1991)
Ross, R. R. & Fabian, A. C. A comprehensive range of X-ray ionized-reflection models. Mon. Not. R. Astron. Soc. 358, 211–216 (2005)
Shara, M. M. & Hurley, J. R. Star clusters as type Ia supernova factories. Astrophys. J. 571, 830–842 (2002)
Uttley, P., McHardy, I. M. & Vaughan, S. Non-linear X-ray variability in X-ray binaries and active galaxies. Mon. Not. R. Astron. Soc. 359, 345–362 (2005)
Arevalo, P. & Uttley, P. Investigating a fluctuating-accretion model for the spectral-timing properties of accreting black hole systems. Mon. Not. R. Astron. Soc. 367, 801–814 (2006)
Bian, W. & Zhao, Y. On X-ray variability in narrow line and broad line active galactic nuclei. Mon. Not. R. Astron. Soc. 343, 164–168 (2003)
Gallo, L. Investigating the nature of narrow-line Seyfert 1 galaxies with high-energy spectral complexity. Mon. Not. R. Astron. Soc. 368, 479–486 (2006)
Acknowledgements
A.C.F. thanks the Royal Society for support. This work is based on observations made with XMM-Newton, a European Space Agency (ESA) science mission with instruments and contributions directly funded by ESA member states and the USA (NASA). A.Z. acknowledges the support of the Algerian Higher Education Ministry and the UK Science and Technology Facilities Council (STFC). C.S.R., W.N.B., G.M., G.P. and R.C.R., and A.J.B. acknowledge support from the US National Science Foundation, NASA, the Spanish Ministerio de Ciencia e Innovacion, the French National Research Agency and the UK STFC for support, respectively.
Author information
Authors and Affiliations
Corresponding author
Supplementary information
Supplementary Information
This file contains Supplementary Notes, Supplementary References and Supplementary Figures 1-8 with Legends. (PDF 489 kb)
Rights and permissions
About this article
Cite this article
Fabian, A., Zoghbi, A., Ross, R. et al. Broad line emission from iron K- and L-shell transitions in the active galaxy 1H 0707-495. Nature 459, 540–542 (2009). https://doi.org/10.1038/nature08007
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature08007
This article is cited by
-
X-ray polarization observations of IC 4329A with IXPE: Constraining the geometry of X-ray corona
Journal of Astrophysics and Astronomy (2023)
-
Coupling between the accreting corona and the relativistic jet in the microquasar GRS 1915+105
Nature Astronomy (2022)
-
XMM-Newton and Swift observations of the Seyfert 1 AGN NGC 5940
Astrophysics and Space Science (2022)
-
Light bending and X-ray echoes from behind a supermassive black hole
Nature (2021)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
