An Intermediate State of Cygnus X-1

Autores
Belloni, Tomaso; Méndez, Mariano R.; Klis, M. van der; Hasinger, Günther; Lewin, Walter H. G.; Paradijs, J. van
Año de publicación
1996
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We report RXTE/PCA observations of the black hole candidate Cygnus X-1. In 1996 February the source was in its usual "low" state. In three observations during 1996 May the source was on average brighter by a factor of 2 and showed less rapid variability and a softer energy spectrum. However, the observations indicate that Cyg X-1 did not enter a high state like the one observed in black hole transients. Flux, variability, and spectral shape suggest instead that the source was in an "intermediate" state similar to what has been observed in GS 1124-68 and GX 339-4. Perhaps also the state transitions of Cyg X-1 observed in the 1970s were not to a high state but to this intermediate state.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
X-rays: stars
stars: individual (Cygnus X-1)
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/123556

id SEDICI_c91046d9ec74ec6ec4d3561341d875cf
oai_identifier_str oai:sedici.unlp.edu.ar:10915/123556
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling An Intermediate State of Cygnus X-1Belloni, TomasoMéndez, Mariano R.Klis, M. van derHasinger, GüntherLewin, Walter H. G.Paradijs, J. vanCiencias AstronómicasX-rays: starsstars: individual (Cygnus X-1)We report RXTE/PCA observations of the black hole candidate Cygnus X-1. In 1996 February the source was in its usual "low" state. In three observations during 1996 May the source was on average brighter by a factor of 2 and showed less rapid variability and a softer energy spectrum. However, the observations indicate that Cyg X-1 did not enter a high state like the one observed in black hole transients. Flux, variability, and spectral shape suggest instead that the source was in an "intermediate" state similar to what has been observed in GS 1124-68 and GX 339-4. Perhaps also the state transitions of Cyg X-1 observed in the 1970s were not to a high state but to this intermediate state.Facultad de Ciencias Astronómicas y Geofísicas1996-12-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfL107-L110http://sedici.unlp.edu.ar/handle/10915/123556enginfo:eu-repo/semantics/altIdentifier/issn/0004-637Xinfo:eu-repo/semantics/altIdentifier/doi/10.1086/310369info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:29:14Zoai:sedici.unlp.edu.ar:10915/123556Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:29:15.072SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv An Intermediate State of Cygnus X-1
title An Intermediate State of Cygnus X-1
spellingShingle An Intermediate State of Cygnus X-1
Belloni, Tomaso
Ciencias Astronómicas
X-rays: stars
stars: individual (Cygnus X-1)
title_short An Intermediate State of Cygnus X-1
title_full An Intermediate State of Cygnus X-1
title_fullStr An Intermediate State of Cygnus X-1
title_full_unstemmed An Intermediate State of Cygnus X-1
title_sort An Intermediate State of Cygnus X-1
dc.creator.none.fl_str_mv Belloni, Tomaso
Méndez, Mariano R.
Klis, M. van der
Hasinger, Günther
Lewin, Walter H. G.
Paradijs, J. van
author Belloni, Tomaso
author_facet Belloni, Tomaso
Méndez, Mariano R.
Klis, M. van der
Hasinger, Günther
Lewin, Walter H. G.
Paradijs, J. van
author_role author
author2 Méndez, Mariano R.
Klis, M. van der
Hasinger, Günther
Lewin, Walter H. G.
Paradijs, J. van
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
X-rays: stars
stars: individual (Cygnus X-1)
topic Ciencias Astronómicas
X-rays: stars
stars: individual (Cygnus X-1)
dc.description.none.fl_txt_mv We report RXTE/PCA observations of the black hole candidate Cygnus X-1. In 1996 February the source was in its usual "low" state. In three observations during 1996 May the source was on average brighter by a factor of 2 and showed less rapid variability and a softer energy spectrum. However, the observations indicate that Cyg X-1 did not enter a high state like the one observed in black hole transients. Flux, variability, and spectral shape suggest instead that the source was in an "intermediate" state similar to what has been observed in GS 1124-68 and GX 339-4. Perhaps also the state transitions of Cyg X-1 observed in the 1970s were not to a high state but to this intermediate state.
Facultad de Ciencias Astronómicas y Geofísicas
description We report RXTE/PCA observations of the black hole candidate Cygnus X-1. In 1996 February the source was in its usual "low" state. In three observations during 1996 May the source was on average brighter by a factor of 2 and showed less rapid variability and a softer energy spectrum. However, the observations indicate that Cyg X-1 did not enter a high state like the one observed in black hole transients. Flux, variability, and spectral shape suggest instead that the source was in an "intermediate" state similar to what has been observed in GS 1124-68 and GX 339-4. Perhaps also the state transitions of Cyg X-1 observed in the 1970s were not to a high state but to this intermediate state.
publishDate 1996
dc.date.none.fl_str_mv 1996-12-01
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/10915/123556
url http://sedici.unlp.edu.ar/handle/10915/123556
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0004-637X
info:eu-repo/semantics/altIdentifier/doi/10.1086/310369
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
L107-L110
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
_version_ 1844616171617255424
score 13.070432