AKARI INFRARED CAMERA OBSERVATIONS OF THE 3.3 μm PAH FEATURE IN Swift/BAT AGNs
AKARI INFRARED CAMERA OBSERVATIONS OF THE 3.3 μm PAH FEATURE IN Swift/BAT AGNs
Angel Castro(Universidad Nacional Autonoma de Mexico); Takamitsu Miyaji(Universidad Nacional Autonoma de Mxico); MAI SHIRAHATA(National Astronomical Observatory of Japan); Kohei Ichikawa(Kyoto University); SHINKI OYABU(Nagoya University); David Clark(Universidad Nacional Autonoma de Mexico); Masatoshi Imanishi(Subaru Telescope); TAKAO NAKAGAWA(Institute of Space and Astronautical Science); Yoshihiro Ueda(Kyoto University)
32권 1호, 197~199쪽
초록
Using the InfraRed Camera (IRC) on board the infrared astronomical satellite {\sl AKARI} we study the 3.3 $\mu$mpolycyclic aromatic hydrocarbon (PAH) feature and its connection to active galactic nucleus (AGN) propertiesfor a sample of 54 hard X-ray selected bright AGN, including both Seyfert 1 and Seyfert 2 type objects. The sample is selected from the 9-month {\sl Swift}/BAT survey in the 14--195 keV band and all of the sources have known neutralhydrogen column densities ($N_{\rm H}$). The 3.3 $\mu$m PAH luminosity ($L_{\rm 3.3{\mu}m}$) is used as a proxy for star-formation (SF)activity and hard X-ray luminosity ($L_{\rm 14-195keV}$) as an indicator of the AGN power. We explore for possible difference of SFactivity between type 1 (un-absorbed) and type 2 (absorbed) AGN. We use several statistical analyses taking the upper-limits of thePAH lines into account utilizing survival analysis methods. The results of our $\log(L_{\rm 14-195keV})$ versus $\log(L_{\rm 3.3{\mu}m})$regression shows a positive correlation and the slope for the type 1/unobscured AGN is steeper than that of type 2/obscured AGN at a$3\sigma$ level. Also our analysis shows that the circum-nuclear SF is more enhanced in type 2/absorbed AGN than type1/un-absorbed AGN for low $L_{\rm 14-195keV}$ luminosity/low Eddington ratio AGN, while there is no significant dependence of SF activityon the AGN type in the high $L_{\rm 14-195keV}$ luminosities/Eddington ratios.
Abstract
Using the InfraRed Camera (IRC) on board the infrared astronomical satellite {\sl AKARI} we study the 3.3 $\mu$mpolycyclic aromatic hydrocarbon (PAH) feature and its connection to active galactic nucleus (AGN) propertiesfor a sample of 54 hard X-ray selected bright AGN, including both Seyfert 1 and Seyfert 2 type objects. The sample is selected from the 9-month {\sl Swift}/BAT survey in the 14--195 keV band and all of the sources have known neutralhydrogen column densities ($N_{\rm H}$). The 3.3 $\mu$m PAH luminosity ($L_{\rm 3.3{\mu}m}$) is used as a proxy for star-formation (SF)activity and hard X-ray luminosity ($L_{\rm 14-195keV}$) as an indicator of the AGN power. We explore for possible difference of SFactivity between type 1 (un-absorbed) and type 2 (absorbed) AGN. We use several statistical analyses taking the upper-limits of thePAH lines into account utilizing survival analysis methods. The results of our $\log(L_{\rm 14-195keV})$ versus $\log(L_{\rm 3.3{\mu}m})$regression shows a positive correlation and the slope for the type 1/unobscured AGN is steeper than that of type 2/obscured AGN at a$3\sigma$ level. Also our analysis shows that the circum-nuclear SF is more enhanced in type 2/absorbed AGN than type1/un-absorbed AGN for low $L_{\rm 14-195keV}$ luminosity/low Eddington ratio AGN, while there is no significant dependence of SF activityon the AGN type in the high $L_{\rm 14-195keV}$ luminosities/Eddington ratios.
- 발행기관:
- 한국천문학회
- 분류:
- 천문학