Abstract
Gamma-ray emission from blazars is known to originate from jets emitted by supermassive black holes1. However, the exact location and size of the γ-ray emitting part of the jets is uncertain2,3,4,5,6. The main difficulty is the very small angular size of these sources, beyond the angular resolution of γ-ray telescopes. Here, we report a measurement of the projected size of the γ-ray jet, revealed by the detection of microlensing in the gravitationally lensed blazar PKS 1830-211. This measurement is consistent with a constraint from the intrinsic variability timescale of the blazar. Our measurement shows that the γ-ray emission originates from the vicinity of the central supermassive black hole. Combining the X-ray and γ-ray data, we use the microlensing effect to constrain the size of the X-ray source. We show that the effect of pair production of γ-rays on X-ray photons does not make the source opaque, owing to the large size of the X-ray emission region.
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Acknowledgements
The work of I.V. is supported by the Swiss National Science Foundation grant P2GEP2_151815. The work of A.N. is supported by the Swiss National Science Foundation grant PP00P2_144923.
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I.V. and D.M. performed the analysis of the Fermi/LAT data. A.N. and I.V. jointly investigated the theoretical aspects of this work. D.M. performed the analysis of the INTERGRAL observations. A.N. and I.V. jointly wrote the paper. All authors took part in discussion of the results and contributed to the manuscript.
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Neronov, A., Vovk, I. & Malyshev, D. Central engine of a gamma-ray blazar resolved through the magnifying glass of gravitational microlensing. Nature Phys 11, 664–667 (2015). https://doi.org/10.1038/nphys3376
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DOI: https://doi.org/10.1038/nphys3376
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