Polycyclic aromatic hydrocarbons and the ionized gas in galaxies with active nuclei

Author(s)

Silva-Ribeiro, A. ^[1] ; Krabbe, A. C. ^[1] ; Canelo, C. M. ^[2] ; Monteiro, A. F. ^[1] ; Sales, Dinalva A. ^[3] ; Hernandez-Jimenez, J. A. ^[1] ; Andrade, D. P. P. ^[4]

Affiliation

^[1] Univ Vale Paraiba, Inst Pesquisa & Desenvolvimento, BR-12244000 Sao Jose Dos Campos - Brazil

^[2] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Dept Astron, BR-05508090 Sao Paulo - Brazil

^[3] Univ Fed Rio Grande, Inst Matemat Estat & Fis, BR-96203900 Rio Grande, RS - Brazil

^[4] Univ Fed Rio de Janeiro, Observ Valongo, BR-20080090 Rio De Janeiro - Brazil

• Document type: Journal article
• Source: Monthly Notices of the Royal Astronomical Society; v. 509, n. 1, p. 327-344, JAN 2022.
• Web of Science Citations: 0

Abstract

We present a study for a sample of galaxies with active nuclei to characterize the main type of PAH molecules present in these objects and the local physical conditions of their irradiating sources, as well as the characteristics of the residing ionized gas, by combining optical and infrared data. Photoionization models were built with the CLOUDY code to reproduce optical emission line ratios in combination with PAH intensity ratios. We find that the species containing 10-82 carbon atoms are the most abundant in the sample. We suggest that family of species with only two or three fused rings of and a nitrogen hanging, such as small aromatic amides are important targets worthy of consideration in future experimental/theoretical as well as observational studies. We find that the AGN photoionization models reproduce most of the observational data in the log (6.2/11.3) versus log ({[}N II] lambda 6584/H alpha) diagram with the optical to X-ray spectral index of alpha(ox) = -1.4. The flux of small PAH, as well as the flux of ionized PAHs and PANH, decrease as the logarithm of the ionization parameter (log U) increases. The 6.2/11.3 PAH intensity ratio presents an anti correlation between the oxygen abundance and log U. Finally, we found that the ionization degree of PAH species increases with the decreasing of the 11.3/7.7 ratio and the log U, in agreement with the models proposed by Draine \& Li. (AU)

• FAPESP's process: 21/08920-8 - Interacting galaxies: new catalog with data from the S-Plus survey and characterization of physical properties with data from the Survey MaNGA.
• Grantee: Jose Andres Hernandez Jimenez
• Support Opportunities: Scholarships in Brazil - Technical Training Program - Technical Training
• FAPESP's process: 20/16416-5 - Interacting galaxies: new catalog with data from the S-Plus survey and characterization of physical properties with data from the Survey MaNGA
• Grantee: Angela Cristina Krabbe
• Support Opportunities: Regular Research Grants