2007/12/04 by F. Massaro, A. Tramacere, A. Cavaliere +2 · 132 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #BL Lac object #Blazar #Context (archaeology) #Curvature #Dark Matter and Cosmic Phenomena #Electron #Gamma ray #Geometry #Nuclear physics #Physics #Spectral line #Spectral shape analysis #Synchrotron #astro-ph
paper · pdf · doi:10.1051/0004-6361:20078639
published in Astronomy and Astrophysics 478(2), 395-401 (EDP Sciences) · 14 pages, 9 figures, A&A accepted
openalex publication_date 2007/12/04 · arxiv created 2007/12/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Context.Many of the extragalactic sources detected in γ rays at TeV energies are BL Lac objects. In particular, they belong to the subclass of “high frequency peaked BL Lacs” (HBLs), as their spectral energy distributions exhibit a first peak in the X-ray band. At a closer look, their X-ray spectra appear to be generally curved into a log-parabolic shape. In a previous investigation of Mrk 421, two correlations were found between the spectral parameters. One involves the height Sp increasing with the position Ep of the first peak; this was interpreted as a signature of synchrotron emission from relativistic electrons. The other involves the curvature parameter b decreasing as Ep increases; this points toward statistical/stochastic acceleration processes for the emitting electrons.