Microlensing as a possible probe of event-horizon structure in quasars
In quasars which are lensed by galaxies, the point-like images sometimes show sharp and uncorrelated brightness variations (microlensing). These brightness changes are associated with the innermost region of the quasar passing through a complicated pattern of caustics produced by the stars in the le...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
08 December 2017
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| In: |
Monthly notices of the Royal Astronomical Society
Year: 2018, Volume: 475, Issue: 2, Pages: 1925-1936 |
| ISSN: | 1365-2966 |
| DOI: | 10.1093/mnras/stx3166 |
| Online Access: | Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1093/mnras/stx3166 Verlag, kostenfrei, Volltext: https://academic.oup.com/mnras/article/475/2/1925/4712234 
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| Author Notes: | Mihai Tomozeiu, Irshad Mohammed, Manuel Rabold, Prasenjit Saha and Joachim Wambsganss |
| Summary: | In quasars which are lensed by galaxies, the point-like images sometimes show sharp and uncorrelated brightness variations (microlensing). These brightness changes are associated with the innermost region of the quasar passing through a complicated pattern of caustics produced by the stars in the lensing galaxy. In this paper, we study whether the universal properties of optical caustics could enable extraction of shape information about the central engine of quasars. We present a toy model with a crescent-shaped source crossing a fold caustic. The silhouette of a black hole over an accretion disc tends to produce roughly crescent sources. When a crescent-shaped source crosses a fold caustic, the resulting light curve is noticeably different from the case of a circular luminosity profile or Gaussian source. With good enough monitoring data, the crescent parameters, apart from one degeneracy, can be recovered. |
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| Item Description: | Gesehen am 16.03.2018 |
| Physical Description: | Online Resource |
| ISSN: | 1365-2966 |
| DOI: | 10.1093/mnras/stx3166 |