A 2.5-5 μm spectroscopic study of hard X-ray selected AGNs using AKARI infrared camera

A. Castro, T. Miyaji, T. Nakagawa, M. Shirahata, S. Oyabu, M. Imanishi, Y. Ueda, K. Ichikawa

Research output: Contribution to journalConference articlepeer-review


We present results of the 2.5-5 μm spectroscopy of a sample of hard X-ray selected active galactic nuclei (AGNs) using the grism mode of the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band, which provides a fair sample of AGNs including highly absorbed ones. The 2.5-5 μm spectroscopy provide a strong diagnostic tool for the circumnuclear environment of AGNs through the continuum shapes and emission/absorption features such as the 3.3 μm polycyclic aromatic hydrocarbon (PAH) emission and the broad 3.1 μm H2O ice, 3.4 μm bare carbonaceous dust, 4.26 μm CO2 and 4.67 μm CO absorptions. As our first step, we use the 3.3 μm PAH emission as a proxy for the star-formation activity and searched for possible difference of star-formation activity between type 1 (unabsorbed) and type 2 (absorbed) AGNs. We found no significant dependence of the 3.3 μm PAH line luminosity, normalized by the black hole mass, on optical AGNs types or the X-ray measured column densities.

Original languageEnglish
Article number068
JournalProceedings of Science
Publication statusPublished - 2012
Externally publishedYes
Event2012 Nuclei of Seyfert Galaxies and QSOs - Central Engine and Conditions of Star Formation, Seyfert 2012 - Bonn, Germany
Duration: 2012 Nov 62012 Nov 8

ASJC Scopus subject areas

  • General

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