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dc.contributor.author
García, Federico
dc.contributor.author
Ranea Sandoval, Ignacio Francisco
dc.contributor.author
Johannsen, Tim
dc.date.available
2019-08-28T19:23:00Z
dc.date.issued
2016-03
dc.identifier.citation
García, Federico; Ranea Sandoval, Ignacio Francisco; Johannsen, Tim; Magnetised accretion discs in Kerr spacetimes: II. Hot spots; EDP Sciences; Astronomy and Astrophysics; 587; 141; 3-2016; 1-7
dc.identifier.issn
0004-6361
dc.identifier.uri
http://hdl.handle.net/11336/82419
dc.description.abstract
Context. Quasi-periodic variability has been observed in a number of X-ray binaries that harbor black hole candidates. In general relativity, black holes are uniquely described by the Kerr metric and, according to the cosmic censorship conjecture, curvature singularities always have to be clothed by an event horizon. Aims. In this paper, we study the observed light curves that arise from orbiting hotspots in thin accretion discs around Kerr black holes and naked singularities, and the effect introduced by the presence of an external magnetic field. Methods. We employ a ray-Tracing algorithm to calculate the light curves and power spectra of these hot spots as seen by a distant observer for uniform and dipolar magnetic field configurations, assuming a weak coupling between the magnetic field and the disc matter. Results. We show that the presence of an external dipolar magnetic field leads to potentially observable modifications of these light curves for both Kerr black holes and naked singularities, while an external uniform magnetic field has practically no effect. In particular, we demonstrate that the emission from a hotspot, which is orbiting near the innermost stable circular orbit of a naked singularity in a dipolar magnetic field, can be significantly harder than the emission of the same hotspot in the absence of this type of magnetic field. Conclusions. The comparison of our model with observational data may allow us to study the geometry of magnetic fields around compact objects and to test the cosmic censorship conjecture in conjunction with other observables, such as thermal continuum spectra and iron line profiles.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
EDP Sciences
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
Accretion
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Accretion Disks
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Black Hole Physics
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Gravitation
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Magnetic Fields
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Relativistic Processes
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X-Rays: Binaries
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Astronomía
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Ciencias Físicas
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CIENCIAS NATURALES Y EXACTAS
dc.title
Magnetised accretion discs in Kerr spacetimes: II. Hot spots
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2019-08-16T16:48:27Z
dc.journal.volume
587
dc.journal.number
141
dc.journal.pagination
1-7
dc.journal.pais
Francia
dc.journal.ciudad
Paris
dc.description.fil
Fil: García, Federico. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina
dc.description.fil
Fil: Ranea Sandoval, Ignacio Francisco. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
dc.description.fil
Fil: Johannsen, Tim. Perimeter Institute For Theoretical Physics; Canadá. University of Waterloo; Canadá
dc.journal.title
Astronomy and Astrophysics
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1051/0004-6361/201527862
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/abs/2016/03/aa27862-15/aa27862-15.html
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