Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification

Autores
Reig, Pablo; Méndez, Mariano R.; van der Klis, M.; Ford, Eric
Año de publicación
2000
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Based on Rossi X-Ray Timing Explorer data, we discuss the classification of the soft X-ray transient Aquila X-1 in the Z/atoll scheme and the relation of its kilohertz quasi-periodic oscillations (kHz QPOs) properties to the X-ray colors. The color-color diagram shows one elongated ("banana") structure and several "islands" of data points. The power spectra of the island are best represented by a broken power law whereas those of the banana by a power law below ~1 Hz plus an exponentially cutoff component at intermediate frequencies (30-60 Hz). The parameters of these two components change in correlation with the position of the source in the color-color diagram. Based on the pattern that the source shows in the color-color diagram and its aperiodic variability, we conclude that Aquila X-1 is an atoll source. We have also investigated the possible correlation between the frequency of the kHz QPOs and the position of the source in the color-color diagram. The complexity seen in the frequency versus count rate diagram is reduced to a single track when the frequency is plotted against hard or soft color.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Astronomía
Ciencias Astronómicas
accretion, accretion disks
stars : individual (Aquila X-1)
stars : neutron
X-rays : stars
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/127256
Acceder
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oai_identifier_str oai:sedici.unlp.edu.ar:10915/127256
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll ClassificationReig, PabloMéndez, Mariano R.van der Klis, M.Ford, EricAstronomíaCiencias Astronómicasaccretion, accretion disksstars : individual (Aquila X-1)stars : neutronX-rays : starsBased on Rossi X-Ray Timing Explorer data, we discuss the classification of the soft X-ray transient Aquila X-1 in the Z/atoll scheme and the relation of its kilohertz quasi-periodic oscillations (kHz QPOs) properties to the X-ray colors. The color-color diagram shows one elongated ("banana") structure and several "islands" of data points. The power spectra of the island are best represented by a broken power law whereas those of the banana by a power law below ~1 Hz plus an exponentially cutoff component at intermediate frequencies (30-60 Hz). The parameters of these two components change in correlation with the position of the source in the color-color diagram. Based on the pattern that the source shows in the color-color diagram and its aperiodic variability, we conclude that Aquila X-1 is an atoll source. We have also investigated the possible correlation between the frequency of the kHz QPOs and the position of the source in the color-color diagram. The complexity seen in the frequency versus count rate diagram is reduced to a single track when the frequency is plotted against hard or soft color.Facultad de Ciencias Astronómicas y Geofísicas2000-02-20info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf916-922http://sedici.unlp.edu.ar/handle/10915/127256enginfo:eu-repo/semantics/altIdentifier/url/https://iopscience.iop.org/article/10.1086/308399info:eu-repo/semantics/altIdentifier/issn/0004-637xinfo:eu-repo/semantics/altIdentifier/issn/1538-4357info:eu-repo/semantics/altIdentifier/doi/10.1086/308399info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International (CC BY 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-10-22T17:11:37Zoai:sedici.unlp.edu.ar:10915/127256Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-10-22 17:11:37.399SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification
title Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification
spellingShingle Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification
Reig, Pablo
Astronomía
Ciencias Astronómicas
accretion, accretion disks
stars : individual (Aquila X-1)
stars : neutron
X-rays : stars
title_short Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification
title_full Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification
title_fullStr Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification
title_full_unstemmed Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification
title_sort Correlated Timing and Spectral Variations of the Soft X-Ray Transient Aquila X-1 : Evidence for an Atoll Classification
dc.creator.none.fl_str_mv Reig, Pablo
Méndez, Mariano R.
van der Klis, M.
Ford, Eric
author Reig, Pablo
author_facet Reig, Pablo
Méndez, Mariano R.
van der Klis, M.
Ford, Eric
author_role author
author2 Méndez, Mariano R.
van der Klis, M.
Ford, Eric
author2_role author
author
author
dc.subject.none.fl_str_mv Astronomía
Ciencias Astronómicas
accretion, accretion disks
stars : individual (Aquila X-1)
stars : neutron
X-rays : stars
topic Astronomía
Ciencias Astronómicas
accretion, accretion disks
stars : individual (Aquila X-1)
stars : neutron
X-rays : stars
dc.description.none.fl_txt_mv Based on Rossi X-Ray Timing Explorer data, we discuss the classification of the soft X-ray transient Aquila X-1 in the Z/atoll scheme and the relation of its kilohertz quasi-periodic oscillations (kHz QPOs) properties to the X-ray colors. The color-color diagram shows one elongated ("banana") structure and several "islands" of data points. The power spectra of the island are best represented by a broken power law whereas those of the banana by a power law below ~1 Hz plus an exponentially cutoff component at intermediate frequencies (30-60 Hz). The parameters of these two components change in correlation with the position of the source in the color-color diagram. Based on the pattern that the source shows in the color-color diagram and its aperiodic variability, we conclude that Aquila X-1 is an atoll source. We have also investigated the possible correlation between the frequency of the kHz QPOs and the position of the source in the color-color diagram. The complexity seen in the frequency versus count rate diagram is reduced to a single track when the frequency is plotted against hard or soft color.
Facultad de Ciencias Astronómicas y Geofísicas
description Based on Rossi X-Ray Timing Explorer data, we discuss the classification of the soft X-ray transient Aquila X-1 in the Z/atoll scheme and the relation of its kilohertz quasi-periodic oscillations (kHz QPOs) properties to the X-ray colors. The color-color diagram shows one elongated ("banana") structure and several "islands" of data points. The power spectra of the island are best represented by a broken power law whereas those of the banana by a power law below ~1 Hz plus an exponentially cutoff component at intermediate frequencies (30-60 Hz). The parameters of these two components change in correlation with the position of the source in the color-color diagram. Based on the pattern that the source shows in the color-color diagram and its aperiodic variability, we conclude that Aquila X-1 is an atoll source. We have also investigated the possible correlation between the frequency of the kHz QPOs and the position of the source in the color-color diagram. The complexity seen in the frequency versus count rate diagram is reduced to a single track when the frequency is plotted against hard or soft color.
publishDate 2000
dc.date.none.fl_str_mv 2000-02-20
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
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://sedici.unlp.edu.ar/handle/10915/127256
url http://sedici.unlp.edu.ar/handle/10915/127256
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://iopscience.iop.org/article/10.1086/308399
info:eu-repo/semantics/altIdentifier/issn/0004-637x
info:eu-repo/semantics/altIdentifier/issn/1538-4357
info:eu-repo/semantics/altIdentifier/doi/10.1086/308399
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International (CC BY 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International (CC BY 4.0)
dc.format.none.fl_str_mv application/pdf
916-922
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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