Testing the evolutionary sequence between hidden broad line region (HBLR) and non-hblr seyfert 2 galaxies with the 4000-Å break strengths

Po Chieh Yu, Kui Yun Huang, Chorng Yuan Hwang, Youichi Ohyama

Research output: Contribution to journalConference articlepeer-review

Abstract

We compared the 4000 Angstrom break (D4000) strength of hidden broad line regions (HBLR) and non-HBLR Seyfert 2 galaxies. Previous studies showed that only about 40% - 45% of Seyfert 2 galaxies show HBLR. The reason of the non-detection of HBLR in some Seyfert 2 galaxies is still under debated. Our results show that the D4000 strength of the non-HBLR Seyfert 2 galaxies is larger than that of HBLR ones, implying that the non-HBLR Seyfert 2 galaxies have older stellar population in the nuclear regions. This suggests that there might be an evolutionary connection between the non-HBLR and HBLR Seyfert 2 galaxies. The gas around the nucleus of the non-HBLR Seyfert 2 galaxies might have diminished in the older age, which would cause low accretion rates. When the accretion rate is below some thresholds, the broad line regions could disappear.

Original languageEnglish
Article number042
JournalProceedings of Science
Volume2012-November
StatePublished - 2012
Event2012 Nuclei of Seyfert Galaxies and QSOs - Central Engine and Conditions of Star Formation, Seyfert 2012 - Bonn, Germany
Duration: 6 Nov 20128 Nov 2012

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