AUTHOR=Foschini Luigi TITLE=What We Talk about When We Talk about Blazars JOURNAL=Frontiers in Astronomy and Space Sciences VOLUME=4 YEAR=2017 URL=https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2017.00006 DOI=10.3389/fspas.2017.00006 ISSN=2296-987X ABSTRACT=

After the discovery of powerful relativistic jets from Narrow-Line Seyfert 1 Galaxies, and the understanding of their similarity with those of blazars, a problem of terminology was born. The word blazar is today associated to BL Lac Objects and Flat-Spectrum Radio Quasars, which are somehow different from Narrow-Line Seyfert 1 Galaxies. Using the same word for all the three classes of AGN could drive either toward some misunderstanding, or to the oversight of some important characteristics. I review the main characteristics of these sources, and finally I propose a new scheme of classification.