Spectral energy distribution template of redshift-zero AGN and the comparison with that of quasars

Abstract

Spectral energy distributions (SEDs) of the central few tens of parsecs of some of the nearest active galactic nuclei [AGN] have been used to construct a genuine redshift-zero SED template [1]. This paper presents the comparison between this redshift-zero template and those of the radio loud and radio quiet quasar templates by [2]. Despite the four orders of magnitude difference in power between the redshift-zero AGNs, mostly Seyfert galaxies, and that of quasars, they all show a remarkable similarity. The distinction relays on the importance of the so-called blue bump component – emission from the accretion disk - which is absent in Seyfert type 2, mildly present in Seyfert type 1, seen in full realm in quasars. Conversely, the characteristic red bump component - dust reprocessed emission in the IR - is present in all cases. The difference between the three AGN classes can be ascribed in terms of central dust obscuration and progressive view angle of the nuclear core.