2000/07/03 by L. Costamante, Costamante, L., G. Ghisellini +23
Economics, Econometrics and Finance · Health Professions · Physics and Astronomy · #Astrophysics (astro-ph) #Economic, financial, and policy analysis #FOS: Physical sciences #Planetary Science and Exploration #Radioactivity and Radon Measurements #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0007020
3 pages; to appear in the proceedings of the Fourth Italian Conference on AGNs (MemSAIt)
arxiv created 2000/07/03 · openalex publication_date 2000/07/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Blazars can be classified on the basis of their overall Spectral Energy Distribution (SED). BL Lac objects are usually divided in LBL or HBL (Low or High energy peaked BL Lacs), according to the peak frequency of the synchrotron emission, if in the optical or UV-soft-X band respectively. FSRQs instead are characterized by synchrotron peaks mainly at IR-optical frequencies, similarly to LBLs. Here we report on recent BeppoSAX observations which are unveiling the high energy branch of the range of synchrotron peak frequencies. Four new "extreme" HBLs have been discovered, one of which (1ES 1426+428) peaks near or above 100 keV, in a quiescent state.