Magnetised accretion discs in Kerr spacetimes: II. Hot spots

Autores
García, Federico; Ranea Sandoval, Ignacio Francisco; Johannsen, Tim
Año de publicación
2016
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
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.
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
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
Fil: Johannsen, Tim. Perimeter Institute For Theoretical Physics; Canadá. University of Waterloo; Canadá
Materia
ACCRETION
ACCRETION DISKS
BLACK HOLE PHYSICS
GRAVITATION
MAGNETIC FIELDS
RELATIVISTIC PROCESSES
X-RAYS: BINARIES
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/82419
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/82419
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Magnetised accretion discs in Kerr spacetimes: II. Hot spotsGarcía, FedericoRanea Sandoval, Ignacio FranciscoJohannsen, TimACCRETIONACCRETION DISKSBLACK HOLE PHYSICSGRAVITATIONMAGNETIC FIELDSRELATIVISTIC PROCESSESX-RAYS: BINARIEShttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1Context. 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.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; ArgentinaFil: Ranea Sandoval, Ignacio Francisco. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Johannsen, Tim. Perimeter Institute For Theoretical Physics; Canadá. University of Waterloo; CanadáEDP Sciences2016-03info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/82419García, 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; 1-70004-6361CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201527862info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/abs/2016/03/aa27862-15/aa27862-15.htmlinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:44:50Zoai:ri.conicet.gov.ar:11336/82419instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:44:50.665CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Magnetised accretion discs in Kerr spacetimes: II. Hot spots
title Magnetised accretion discs in Kerr spacetimes: II. Hot spots
spellingShingle Magnetised accretion discs in Kerr spacetimes: II. Hot spots
García, Federico
ACCRETION
ACCRETION DISKS
BLACK HOLE PHYSICS
GRAVITATION
MAGNETIC FIELDS
RELATIVISTIC PROCESSES
X-RAYS: BINARIES
title_short Magnetised accretion discs in Kerr spacetimes: II. Hot spots
title_full Magnetised accretion discs in Kerr spacetimes: II. Hot spots
title_fullStr Magnetised accretion discs in Kerr spacetimes: II. Hot spots
title_full_unstemmed Magnetised accretion discs in Kerr spacetimes: II. Hot spots
title_sort Magnetised accretion discs in Kerr spacetimes: II. Hot spots
dc.creator.none.fl_str_mv García, Federico
Ranea Sandoval, Ignacio Francisco
Johannsen, Tim
author García, Federico
author_facet García, Federico
Ranea Sandoval, Ignacio Francisco
Johannsen, Tim
author_role author
author2 Ranea Sandoval, Ignacio Francisco
Johannsen, Tim
author2_role author
author
dc.subject.none.fl_str_mv ACCRETION
ACCRETION DISKS
BLACK HOLE PHYSICS
GRAVITATION
MAGNETIC FIELDS
RELATIVISTIC PROCESSES
X-RAYS: BINARIES
topic ACCRETION
ACCRETION DISKS
BLACK HOLE PHYSICS
GRAVITATION
MAGNETIC FIELDS
RELATIVISTIC PROCESSES
X-RAYS: BINARIES
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv 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.
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
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
Fil: Johannsen, Tim. Perimeter Institute For Theoretical Physics; Canadá. University of Waterloo; Canadá
description 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.
publishDate 2016
dc.date.none.fl_str_mv 2016-03
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/82419
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
0004-6361
CONICET Digital
CONICET
url http://hdl.handle.net/11336/82419
identifier_str_mv 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
0004-6361
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201527862
info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/abs/2016/03/aa27862-15/aa27862-15.html
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv EDP Sciences
publisher.none.fl_str_mv EDP Sciences
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
_version_ 1844613410667364352
score 13.070432

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