The Eddington ratio-dependent ‘changing look’ events in NGC 2992
Autor(a) principal: | |
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Data de Publicação: | 2021 |
Outros Autores: | , , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/233029 |
Resumo: | We present an analysis of historical multiwavelength emission of the `Changing Look’ (CL) Active Galactic Nucleu (AGN) in NGC 2992, covering epochs ranging from 1978 to 2021, as well as new X-ray and optical spectra. The galaxy presents multiple Seyfert type transitions from Type 2 to intermediate-type, losing and regaining its Hα broad emission lines (BEL) recurrently. In X-rays, the source shows intrinsic variability with the absorption corrected luminosity varying by a factor of ∼ 40. We rule-out tidal disruption events or variable obscuration as causes of the type transitions, and show that the presence and the flux of th Hα BEL is directly correlated with the 2–10 keV X-ray luminosity (L2−10): the component disappears at L2−10 ≤ 2.6 × 1042 erg cm−2 s−1; this luminosity value translates into an Eddington ratio (λEdd) of ∼ 1 per cent. The λEdd in which the BEL transitions occur is the same as the critical value at which a state transition between a radiatively inefficient accretion flow and a thin accretion disk is expected, such similarity suggests that the AGN is operating at the threshold mass accretion rate between the two accretion modes. We find a correlation between the narrow Fe Kα flux and λEdd, and an anticorrelation between full-width at half maximum of Hα BEL and λEdd, in agreement with theoretical predictions. Two possible scenarios for type transitions are compatible with our results: either the dimming of the AGN continuum, which reduces the supply of ionizing photons available to excite the gas in the Broad Line Region (BLR), or the fading of the BLR structure itself occurs as the low accretion rate is not able to sustain the required cloud flow rate in a disc-wind BLR model. |
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Pereira, Muryel GuoloDutra, Daniel RuschelGrupe, DirkPeterson, Bradley M.Storchi-Bergmann, ThaisaSchimoia, Jáderson da SilvaNemmen, Rodrigo S.Robinson, Andrew2021-12-17T04:30:08Z20210035-8711http://hdl.handle.net/10183/233029001132795We present an analysis of historical multiwavelength emission of the `Changing Look’ (CL) Active Galactic Nucleu (AGN) in NGC 2992, covering epochs ranging from 1978 to 2021, as well as new X-ray and optical spectra. The galaxy presents multiple Seyfert type transitions from Type 2 to intermediate-type, losing and regaining its Hα broad emission lines (BEL) recurrently. In X-rays, the source shows intrinsic variability with the absorption corrected luminosity varying by a factor of ∼ 40. We rule-out tidal disruption events or variable obscuration as causes of the type transitions, and show that the presence and the flux of th Hα BEL is directly correlated with the 2–10 keV X-ray luminosity (L2−10): the component disappears at L2−10 ≤ 2.6 × 1042 erg cm−2 s−1; this luminosity value translates into an Eddington ratio (λEdd) of ∼ 1 per cent. The λEdd in which the BEL transitions occur is the same as the critical value at which a state transition between a radiatively inefficient accretion flow and a thin accretion disk is expected, such similarity suggests that the AGN is operating at the threshold mass accretion rate between the two accretion modes. We find a correlation between the narrow Fe Kα flux and λEdd, and an anticorrelation between full-width at half maximum of Hα BEL and λEdd, in agreement with theoretical predictions. Two possible scenarios for type transitions are compatible with our results: either the dimming of the AGN continuum, which reduces the supply of ionizing photons available to excite the gas in the Broad Line Region (BLR), or the fading of the BLR structure itself occurs as the low accretion rate is not able to sustain the required cloud flow rate in a disc-wind BLR model.application/pdfengMonthly notices of the royal astronomical society. Oxford. Vol. 508, no. 1 (Nov. 2021), p. 144-156Nucleo galaticoGalaxias seyfertGalaxies: nucleiGalaxies: SeyfertX-rays: galaxiesThe Eddington ratio-dependent ‘changing look’ events in NGC 2992Estrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSTEXT001132795.pdf.txt001132795.pdf.txtExtracted Texttext/plain75772http://www.lume.ufrgs.br/bitstream/10183/233029/2/001132795.pdf.txtf7a51ce34c7b9bfad9d353ab6b7ec2faMD52ORIGINAL001132795.pdfTexto completo (inglês)application/pdf785418http://www.lume.ufrgs.br/bitstream/10183/233029/1/001132795.pdf770480faa3aad12a71e3d130976b0761MD5110183/2330292022-01-07 05:26:52.370195oai:www.lume.ufrgs.br:10183/233029Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2022-01-07T07:26:52Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
The Eddington ratio-dependent ‘changing look’ events in NGC 2992 |
title |
The Eddington ratio-dependent ‘changing look’ events in NGC 2992 |
spellingShingle |
The Eddington ratio-dependent ‘changing look’ events in NGC 2992 Pereira, Muryel Guolo Nucleo galatico Galaxias seyfert Galaxies: nuclei Galaxies: Seyfert X-rays: galaxies |
title_short |
The Eddington ratio-dependent ‘changing look’ events in NGC 2992 |
title_full |
The Eddington ratio-dependent ‘changing look’ events in NGC 2992 |
title_fullStr |
The Eddington ratio-dependent ‘changing look’ events in NGC 2992 |
title_full_unstemmed |
The Eddington ratio-dependent ‘changing look’ events in NGC 2992 |
title_sort |
The Eddington ratio-dependent ‘changing look’ events in NGC 2992 |
author |
Pereira, Muryel Guolo |
author_facet |
Pereira, Muryel Guolo Dutra, Daniel Ruschel Grupe, Dirk Peterson, Bradley M. Storchi-Bergmann, Thaisa Schimoia, Jáderson da Silva Nemmen, Rodrigo S. Robinson, Andrew |
author_role |
author |
author2 |
Dutra, Daniel Ruschel Grupe, Dirk Peterson, Bradley M. Storchi-Bergmann, Thaisa Schimoia, Jáderson da Silva Nemmen, Rodrigo S. Robinson, Andrew |
author2_role |
author author author author author author author |
dc.contributor.author.fl_str_mv |
Pereira, Muryel Guolo Dutra, Daniel Ruschel Grupe, Dirk Peterson, Bradley M. Storchi-Bergmann, Thaisa Schimoia, Jáderson da Silva Nemmen, Rodrigo S. Robinson, Andrew |
dc.subject.por.fl_str_mv |
Nucleo galatico Galaxias seyfert |
topic |
Nucleo galatico Galaxias seyfert Galaxies: nuclei Galaxies: Seyfert X-rays: galaxies |
dc.subject.eng.fl_str_mv |
Galaxies: nuclei Galaxies: Seyfert X-rays: galaxies |
description |
We present an analysis of historical multiwavelength emission of the `Changing Look’ (CL) Active Galactic Nucleu (AGN) in NGC 2992, covering epochs ranging from 1978 to 2021, as well as new X-ray and optical spectra. The galaxy presents multiple Seyfert type transitions from Type 2 to intermediate-type, losing and regaining its Hα broad emission lines (BEL) recurrently. In X-rays, the source shows intrinsic variability with the absorption corrected luminosity varying by a factor of ∼ 40. We rule-out tidal disruption events or variable obscuration as causes of the type transitions, and show that the presence and the flux of th Hα BEL is directly correlated with the 2–10 keV X-ray luminosity (L2−10): the component disappears at L2−10 ≤ 2.6 × 1042 erg cm−2 s−1; this luminosity value translates into an Eddington ratio (λEdd) of ∼ 1 per cent. The λEdd in which the BEL transitions occur is the same as the critical value at which a state transition between a radiatively inefficient accretion flow and a thin accretion disk is expected, such similarity suggests that the AGN is operating at the threshold mass accretion rate between the two accretion modes. We find a correlation between the narrow Fe Kα flux and λEdd, and an anticorrelation between full-width at half maximum of Hα BEL and λEdd, in agreement with theoretical predictions. Two possible scenarios for type transitions are compatible with our results: either the dimming of the AGN continuum, which reduces the supply of ionizing photons available to excite the gas in the Broad Line Region (BLR), or the fading of the BLR structure itself occurs as the low accretion rate is not able to sustain the required cloud flow rate in a disc-wind BLR model. |
publishDate |
2021 |
dc.date.accessioned.fl_str_mv |
2021-12-17T04:30:08Z |
dc.date.issued.fl_str_mv |
2021 |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/233029 |
dc.identifier.issn.pt_BR.fl_str_mv |
0035-8711 |
dc.identifier.nrb.pt_BR.fl_str_mv |
001132795 |
identifier_str_mv |
0035-8711 001132795 |
url |
http://hdl.handle.net/10183/233029 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Monthly notices of the royal astronomical society. Oxford. Vol. 508, no. 1 (Nov. 2021), p. 144-156 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
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openAccess |
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