Physical conditions of the coronal line region in Seyfert 2 galaxies

• Main Authors: Daza, J.A (Author), Portilla, J.G (Author)
• Format: Article
• Language: English
• Published: Colombian Academy of Exact, Physical and Natural Sciences 2021
• Subjects: AGN; Coronal lines; Photoionization; Seyfert 2 galaxies
• Online Access: View Fulltext in Publisher

 Recent studies indicate that the region of emission of coronal lines observed in some active galactic nuclei is located in the internal face of the obscurant toroid; however, there are numerous examples of Seyfert 2 galaxies with significant coronal emission. To clarify this anomaly, here we give some insights about the location of the coronal line region (CLR) and determine the physical conditions of the coronal gas in this type of galaxies. We executed a SQL query in the Sloan Digital Sky Survey (SDSS-DR14) database to select various Seyfert 2 galaxies under the following criteria: 3<[O III] λ5007/Hβ<16, 0.5<[N II] λ6584/Hα<2, 0.3<([S II] λ6717+ λ6731)/Hα<0.6, 0.06<[O I] λ6300/Hα<0.2 and 0.02< z <0.13. This procedure yielded 497 Seyfert 2 galaxies. From these, the simultaneous emission of the four optical forbidden lines of [Fe VII] λλλλ6087, 5721, 5158, 3759 was found only in 10 objects. Flux ratios of these four lines enable to set ranges of density (Ne) and electronic temperature (Te) of the CLR through two ways allowing for a better approximation to these values. We found a correlation between the Narrow Line Region (NLR) and the CLR temperatures suggesting some kind of physical connection between the two zones for this type of objects when we compared these values with those from NLR. © 2021 Colombian Academy of Exact, Physical and Natural Sciences. All rights reserved.