Mapping low- and high-density clouds in astrophysical nebulae by imaging forbidden line emission

Autor(es)

Steiner, J. E. ^[1] ; Menezes, R. B. ^[1] ; Ricci, T. V. ^[1] ; Oliveira, A. S. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil

^[2] Univ Vale Paraiba, IP & D, BR-12244000 Sao Jose Dos Campos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 396, n. 2, p. 788-793, June 2009.
• Área do conhecimento: Ciências Exatas e da Terra - Astronomia
• Citações Web of Science: 6
• Assunto(s): Galáxias ativas Meio interestelar Nuvens Espectroscopia óptica

Resumo

Emission line ratios have been essential for determining physical parameters such as gas temperature and density in astrophysical gaseous nebulae. With the advent of panoramic spectroscopic devices, images of regions with emission lines related to these physical parameters can, in principle, also be produced. We show that, with observations from modern instruments, it is possible to transform images taken from density-sensitive forbidden lines into images of emission from high- and low-density clouds by applying a transformation matrix. In order to achieve this, images of the pairs of density-sensitive lines as well as the adjacent continuum have to be observed and combined. We have computed the critical densities for a series of pairs of lines in the infrared, optical, ultraviolet and X-rays bands, and calculated the pair line intensity ratios in the high- and low-density limit using a four- and five-level atom approximation. In order to illustrate the method, we applied it to Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (GMOS-IFU) data of two galactic nuclei. We conclude that this method provides new information of astrophysical interest, especially for mapping low- and high-density clouds; for this reason, we call it 'the ld/hd imaging method'. (AU)

• Processo FAPESP: 05/03323-9 - Análise de componentes principais de uma amostra de galáxias Seyferts próximas
• Beneficiário: Tiago Vecchi Ricci
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 06/05203-3 - Diferenciação de modelos para LINERs
• Beneficiário: Roberto Bertoldo Menezes
• Modalidade de apoio: Bolsas no Brasil - Mestrado