Possible γ-ray emission of radio intermediate AGN Ⅲ Zw 2 and its implication on the evolution of jets in AGNs  

作　　者：Liang Chen Jin-Ming Bai Jin Zhang Hong-Tao Liu 

机构地区：[1]National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011, China [2]Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011, China [3]Graduate University of Chinese Academy of Sciences, Beijing 100049, China [4]College of Physics and Electronic Engineering, Guangxi Teachers Education University, Nanning 530001, China

出　　处：《Research in Astronomy and Astrophysics》2010年第8期707-712,共6页天文和天体物理学研究（英文版）

基　　金：the West Ph.D. project of the Training Programme for the Talents of the West Light Foundation of the CAS;the National Natural Science Foundation of China (NSFC;Grant Nos.10903025 and 10778702) for financial support;the National Natural Science Foundation of China (Grant No.10973034);the 973 Program (Grant No.2009CB824800)

摘　　要：AGNs with hard γ-ray emission identified so far are radio-loud. Ⅲ Zw 2 is a radio intermediate AGN with a relativistic jet. We study its spectral energy distribution （SED） and find that the broad band emissions are dominated by the nonthermal emissions from the jet. We model its SED through a synchrotron ＋ inverse Compton （IC） model. The results show that the IC component of Ⅲ Zw 2 peaks at a few MeV, and the flux density drops rapidly at higher energy with photon index F 3.3 above 0.1 GeV. The predicted flux is slightly over the sensitivity of Fermi/LAT, but it was not included in the first Fermi/LAT AGN catalog. The reason for this may be： 1） that the IC peak is low and the spectrum is very steep above 0.1 GeV, 2） that Ⅲ Zw 2 is in the low state during the period of the Fermi/LAT operation. We also find that Ⅲ Zw 2 follows similar jet processes as those in γ-ray AGNs, e.g., the relation between jet power and radiation power, which is called the blazar sequence. We suggest that Ⅲ Zw 2 may be a young source at an earlier stage of jet activity.AGNs with hard γ-ray emission identified so far are radio-loud. Ⅲ Zw 2 is a radio intermediate AGN with a relativistic jet. We study its spectral energy distribution （SED） and find that the broad band emissions are dominated by the nonthermal emissions from the jet. We model its SED through a synchrotron ＋ inverse Compton （IC） model. The results show that the IC component of Ⅲ Zw 2 peaks at a few MeV, and the flux density drops rapidly at higher energy with photon index F 3.3 above 0.1 GeV. The predicted flux is slightly over the sensitivity of Fermi/LAT, but it was not included in the first Fermi/LAT AGN catalog. The reason for this may be： 1） that the IC peak is low and the spectrum is very steep above 0.1 GeV, 2） that Ⅲ Zw 2 is in the low state during the period of the Fermi/LAT operation. We also find that Ⅲ Zw 2 follows similar jet processes as those in γ-ray AGNs, e.g., the relation between jet power and radiation power, which is called the blazar sequence. We suggest that Ⅲ Zw 2 may be a young source at an earlier stage of jet activity.

关 键 词：GALAXIES active -- galaxies Seyfert- galaxies jets -- radiation mechanisms NON-THERMAL 

分 类 号：O442[理学—电磁学] P157.6[理学—物理]