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High frequency peakers
Author(s) -
Orienti M.
Publication year - 2009
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200811147
Subject(s) - physics , blazar , context (archaeology) , astrophysics , radio spectrum , radio frequency , class (philosophy) , active galactic nucleus , simple (philosophy) , astronomy , computer science , telecommunications , galaxy , geology , artificial intelligence , paleontology , gamma ray , philosophy , epistemology
High Frequency Peaker (HFP) radio sources are an extreme class of active galactic nuclei whose nature has not been fully understood yet. They are compact objects with a simple convex radio spectrum which turns over at frequencies well above a few GHz. In the context of evolutionary models such sources are likely to represent the earliest stage in individual radio source evolution, with typical ages of a few hundred years. However, the selection tools used to identify a source as an HFP are based on the spectral shape and can introduce a contamination by beamed blazar objects. The study of their radio properties provides us with important information on their nature and on the ambient medium in which they are evolving (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)