The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta

Autores
Nicholl, M.; Berger, E.; Kasen, D.; Metzger, B. D.; Elias, J.; Briceño, C.; Alexander, K. D.; Blanchard, P. K.; Chornock, R.; Cowperthwaite, P. S.; Eftekhari, T.; Fong, W.; Margutti, R.; Villar, V. A.; Williams, P. K. G.; Brown, W.; Annis, J.; Bahramian, A.; Brout, D.; Brown, D. A.; Chen, H. Y.; Clemens, J. C.; Dennihy, E.; Dunlap, B.; Holz, D. E.; Marchesini, Ezequiel Joaquín; Massaro, F.; Moskowitz, N.; Pelisoli, I.; Rest, A.; Ricci, F.; Sako, M.; Soares-Santos, M.; Strader, J.
Año de publicación
2017
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We present optical and ultraviolet spectra of the first electromagnetic counterpart to a gravitational-wave (GW) source, the binary neutron star merger GW170817. Spectra were obtained nightly between 1.5 and 9.5 days post-merger, using the Southern Astrophysical Research and Magellan telescopes; the UV spectrum was obtained with the Hubble Space Telescope at 5.5 days. Our data reveal a rapidly fading blue component (T ≈ 5500 K at 1.5 days) that quickly reddens; spectra later than ≳4.5 days peak beyond the optical regime. The spectra are mostly featureless, although we identify a possible weak emission line at ∼7900 Å; at t ≲ 4.5 days. The colors, rapid evolution, and featureless spectrum are consistent with a "blue" kilonova from polar ejecta comprised mainly of light r-process nuclei with atomic mass number A ≲ 140. This indicates a sightline within θobs ≲ 45° of the orbital axis. Comparison to models suggests ∼0.03 M o of blue ejecta, with a velocity of . The required lanthanide fraction is ∼10-4, but this drops to <10-5in the outermost ejecta. The large velocities point to a dynamical origin, rather than a disk wind, for this blue component, suggesting that both binary constituents are neutron stars (as opposed to a binary consisting of a neutron star and a black hole). For dynamical ejecta, the high mass favors a small neutron star radius of ≲12 km. This mass also supports the idea that neutron star mergers are a major contributor to r-process nucleosynthesis.
La lista completa de autores que integran el documento puede consultarse en el archivo
Instituto de Astrofísica de La Plata
Materia
Física
binaries: close
gravitational waves
nuclear reactions, nucleosynthesis, abundances
stars: neutron
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:10915/87367

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network_name_str SEDICI (UNLP)
spelling The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar EjectaNicholl, M.Berger, E.Kasen, D.Metzger, B. D.Elias, J.Briceño, C.Alexander, K. D.Blanchard, P. K.Chornock, R.Cowperthwaite, P. S.Eftekhari, T.Fong, W.Margutti, R.Villar, V. A.Williams, P. K. G.Brown, W.Annis, J.Bahramian, A.Brout, D.Brown, D. A.Chen, H. Y.Clemens, J. C.Dennihy, E.Dunlap, B.Holz, D. E.Marchesini, Ezequiel JoaquínMassaro, F.Moskowitz, N.Pelisoli, I.Rest, A.Ricci, F.Sako, M.Soares-Santos, M.Strader, J.Físicabinaries: closegravitational wavesnuclear reactions, nucleosynthesis, abundancesstars: neutronWe present optical and ultraviolet spectra of the first electromagnetic counterpart to a gravitational-wave (GW) source, the binary neutron star merger GW170817. Spectra were obtained nightly between 1.5 and 9.5 days post-merger, using the Southern Astrophysical Research and Magellan telescopes; the UV spectrum was obtained with the Hubble Space Telescope at 5.5 days. Our data reveal a rapidly fading blue component (T ≈ 5500 K at 1.5 days) that quickly reddens; spectra later than ≳4.5 days peak beyond the optical regime. The spectra are mostly featureless, although we identify a possible weak emission line at ∼7900 Å; at t ≲ 4.5 days. The colors, rapid evolution, and featureless spectrum are consistent with a "blue" kilonova from polar ejecta comprised mainly of light r-process nuclei with atomic mass number A ≲ 140. This indicates a sightline within θobs ≲ 45° of the orbital axis. Comparison to models suggests ∼0.03 M o of blue ejecta, with a velocity of . The required lanthanide fraction is ∼10-4, but this drops to <10-5in the outermost ejecta. The large velocities point to a dynamical origin, rather than a disk wind, for this blue component, suggesting that both binary constituents are neutron stars (as opposed to a binary consisting of a neutron star and a black hole). For dynamical ejecta, the high mass favors a small neutron star radius of ≲12 km. This mass also supports the idea that neutron star mergers are a major contributor to r-process nucleosynthesis.La lista completa de autores que integran el documento puede consultarse en el archivoInstituto de Astrofísica de La Plata2017-10-20info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/87367enginfo:eu-repo/semantics/altIdentifier/issn/2041-8205info:eu-repo/semantics/altIdentifier/doi/10.3847/2041-8213/aa9029info: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:UNLP2025-09-29T11:17:10Zoai:sedici.unlp.edu.ar:10915/87367Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:17:10.291SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
title The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
spellingShingle The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
Nicholl, M.
Física
binaries: close
gravitational waves
nuclear reactions, nucleosynthesis, abundances
stars: neutron
title_short The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
title_full The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
title_fullStr The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
title_full_unstemmed The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
title_sort The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta
dc.creator.none.fl_str_mv Nicholl, M.
Berger, E.
Kasen, D.
Metzger, B. D.
Elias, J.
Briceño, C.
Alexander, K. D.
Blanchard, P. K.
Chornock, R.
Cowperthwaite, P. S.
Eftekhari, T.
Fong, W.
Margutti, R.
Villar, V. A.
Williams, P. K. G.
Brown, W.
Annis, J.
Bahramian, A.
Brout, D.
Brown, D. A.
Chen, H. Y.
Clemens, J. C.
Dennihy, E.
Dunlap, B.
Holz, D. E.
Marchesini, Ezequiel Joaquín
Massaro, F.
Moskowitz, N.
Pelisoli, I.
Rest, A.
Ricci, F.
Sako, M.
Soares-Santos, M.
Strader, J.
author Nicholl, M.
author_facet Nicholl, M.
Berger, E.
Kasen, D.
Metzger, B. D.
Elias, J.
Briceño, C.
Alexander, K. D.
Blanchard, P. K.
Chornock, R.
Cowperthwaite, P. S.
Eftekhari, T.
Fong, W.
Margutti, R.
Villar, V. A.
Williams, P. K. G.
Brown, W.
Annis, J.
Bahramian, A.
Brout, D.
Brown, D. A.
Chen, H. Y.
Clemens, J. C.
Dennihy, E.
Dunlap, B.
Holz, D. E.
Marchesini, Ezequiel Joaquín
Massaro, F.
Moskowitz, N.
Pelisoli, I.
Rest, A.
Ricci, F.
Sako, M.
Soares-Santos, M.
Strader, J.
author_role author
author2 Berger, E.
Kasen, D.
Metzger, B. D.
Elias, J.
Briceño, C.
Alexander, K. D.
Blanchard, P. K.
Chornock, R.
Cowperthwaite, P. S.
Eftekhari, T.
Fong, W.
Margutti, R.
Villar, V. A.
Williams, P. K. G.
Brown, W.
Annis, J.
Bahramian, A.
Brout, D.
Brown, D. A.
Chen, H. Y.
Clemens, J. C.
Dennihy, E.
Dunlap, B.
Holz, D. E.
Marchesini, Ezequiel Joaquín
Massaro, F.
Moskowitz, N.
Pelisoli, I.
Rest, A.
Ricci, F.
Sako, M.
Soares-Santos, M.
Strader, J.
author2_role author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Física
binaries: close
gravitational waves
nuclear reactions, nucleosynthesis, abundances
stars: neutron
topic Física
binaries: close
gravitational waves
nuclear reactions, nucleosynthesis, abundances
stars: neutron
dc.description.none.fl_txt_mv We present optical and ultraviolet spectra of the first electromagnetic counterpart to a gravitational-wave (GW) source, the binary neutron star merger GW170817. Spectra were obtained nightly between 1.5 and 9.5 days post-merger, using the Southern Astrophysical Research and Magellan telescopes; the UV spectrum was obtained with the Hubble Space Telescope at 5.5 days. Our data reveal a rapidly fading blue component (T ≈ 5500 K at 1.5 days) that quickly reddens; spectra later than ≳4.5 days peak beyond the optical regime. The spectra are mostly featureless, although we identify a possible weak emission line at ∼7900 Å; at t ≲ 4.5 days. The colors, rapid evolution, and featureless spectrum are consistent with a "blue" kilonova from polar ejecta comprised mainly of light r-process nuclei with atomic mass number A ≲ 140. This indicates a sightline within θobs ≲ 45° of the orbital axis. Comparison to models suggests ∼0.03 M o of blue ejecta, with a velocity of . The required lanthanide fraction is ∼10-4, but this drops to <10-5in the outermost ejecta. The large velocities point to a dynamical origin, rather than a disk wind, for this blue component, suggesting that both binary constituents are neutron stars (as opposed to a binary consisting of a neutron star and a black hole). For dynamical ejecta, the high mass favors a small neutron star radius of ≲12 km. This mass also supports the idea that neutron star mergers are a major contributor to r-process nucleosynthesis.
La lista completa de autores que integran el documento puede consultarse en el archivo
Instituto de Astrofísica de La Plata
description We present optical and ultraviolet spectra of the first electromagnetic counterpart to a gravitational-wave (GW) source, the binary neutron star merger GW170817. Spectra were obtained nightly between 1.5 and 9.5 days post-merger, using the Southern Astrophysical Research and Magellan telescopes; the UV spectrum was obtained with the Hubble Space Telescope at 5.5 days. Our data reveal a rapidly fading blue component (T ≈ 5500 K at 1.5 days) that quickly reddens; spectra later than ≳4.5 days peak beyond the optical regime. The spectra are mostly featureless, although we identify a possible weak emission line at ∼7900 Å; at t ≲ 4.5 days. The colors, rapid evolution, and featureless spectrum are consistent with a "blue" kilonova from polar ejecta comprised mainly of light r-process nuclei with atomic mass number A ≲ 140. This indicates a sightline within θobs ≲ 45° of the orbital axis. Comparison to models suggests ∼0.03 M o of blue ejecta, with a velocity of . The required lanthanide fraction is ∼10-4, but this drops to <10-5in the outermost ejecta. The large velocities point to a dynamical origin, rather than a disk wind, for this blue component, suggesting that both binary constituents are neutron stars (as opposed to a binary consisting of a neutron star and a black hole). For dynamical ejecta, the high mass favors a small neutron star radius of ≲12 km. This mass also supports the idea that neutron star mergers are a major contributor to r-process nucleosynthesis.
publishDate 2017
dc.date.none.fl_str_mv 2017-10-20
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/10915/87367
url http://sedici.unlp.edu.ar/handle/10915/87367
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/2041-8205
info:eu-repo/semantics/altIdentifier/doi/10.3847/2041-8213/aa9029
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
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
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reponame_str SEDICI (UNLP)
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instname_str Universidad Nacional de La Plata
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institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
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