X-rays as the dominant excitation mechanism of [Fe II] and H2 emission lines in active galaxies

We investigate the excitation mechanisms of near-infrared [Fe II] and H2 emission lines observed in active galactic nuclei (AGNs). We built a photoionization model grid considering a two-component continuum: one component accounts for the `big bump´ component peaking at 1Ryd and another represents t...

Descripción completa

Detalles Bibliográficos
Autores: Dors, Oli L., Riffel, Rogemar A., Cardaci, Monica Viviana, Hägele, Guillermo Federico, Krabbe, Angela, Pérez Montero, Enrique, Rodrigues, Irapuan
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2012
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/42650
Acceso en línea:http://hdl.handle.net/11336/42650
Access Level:acceso abierto
Palabra clave:Galaxies
Seyfert galaxies
Infrared galaxies
Interstellar medium
https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
Descripción
Sumario:We investigate the excitation mechanisms of near-infrared [Fe II] and H2 emission lines observed in active galactic nuclei (AGNs). We built a photoionization model grid considering a two-component continuum: one component accounts for the `big bump´ component peaking at 1Ryd and another represents the X-ray source that dominates the continuum emission at high energies. Photoionization models considering as ionizing source a spectral energy distribution obtained from photometric data of Seyfert 2 Mrk 1066 taken from the literature were considered. Results of these models were compared with a large sample of observational long-slit and Integral field Unit (IFU) spectroscopy data of the nuclear region for a sample of active objects. We found that the correlation between the observational [Fe II] lambda 1.2570μm/Pa beta and H2 lambda 2.1218μm/Brγ is well reproduced by our models, as are the relationships that involve the H2 emission-line ratios observed in the spectroscopic data. We conclude that heating by X-rays produced by active nuclei can be considered a common and very important mechanism of excitation of [Fe II] and H2.