水村 好貴

Recently, the numbers of discoveries of AGNs in GeV and sub-TeV energy bands have increased rapidly. Many simultaneous multiwavelength campaigns for AGN are performed and physical mechanisms are discussed aggressively. We select four Fermi AGNs from three sub-class of blazars, and discuss the quasi-simultaneous multiwavelength spectra using a simple leptonic jet model. For two HBLs (H 2356-309 and PKS 2155-304), the SEDs can be explained by a one-zone synchrotron self-Compton (SSC) scenario, and obtained parameters are almost in the range of typical HBL values. In the case of LBL (PKS 0537-441) and FSRQ (3C 279), our SSC model cannot explain the observed SEDs, and may require an introduction of another component, such as inverse Compton radiation with external photons.

CANGAROO-III observations of several extragalactic objects have been made since its launch. Here we present the results for two BL Lac objects (H 2356-309 and PKS 2155-304) and one starburst galaxy (M 83). H2356-309 was observed in July and August 2005. The quality selected data for a total live time of 26 hours are analyzed, and no excess events in the direction of H2356-309 are found. The upper limit of the gamma-ray flux above 750 GeV is calculated. Observations of M83 were done in Mar 2005 for 4 nights. No significant excess events was found, and the flux upper limit was obtained above 490 GeV. We have observed the well-known HBL, PKS 2155-304(z = 0.116), for 19 nights from July to September 2008 with the CANGAROO-III telescopes including the multiwavelength campaign periods. No significant excess signal was detected, and the average integral flux upper limit was calculated above 720 GeV.