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Title: RADIUS CONSTRAINTS AND MINIMAL EQUIPARTITION ENERGY OF RELATIVISTICALLY MOVING SYNCHROTRON SOURCES

A measurement of the synchrotron self-absorption flux and frequency provides tight constraints on the physical size of the source and a robust lower limit on its energy. This lower limit is also a good estimate of the magnetic field and electrons' energy, if the two components are at equipartition. This well-known method was used for decades to study numerous astrophysical sources moving at non-relativistic (Newtonian) speeds. Here, we generalize the Newtonian equipartition theory to sources moving at relativistic speeds including the effect of deviation from spherical symmetry expected in such sources. As in the Newtonian case, minimization of the energy provides an excellent estimate of the emission radius and yields a useful lower limit on the energy. We find that the application of the Newtonian formalism to a relativistic source would yield a smaller emission radius, and would generally yield a larger lower limit on the energy (within the observed region). For sources where the synchrotron-self-Compton component can be identified, the minimization of the total energy is not necessary and we present an unambiguous solution for the parameters of the system.
Authors:
;  [1] ;  [2]
  1. Racah Institute for Physics, Hebrew University, Jerusalem 91904 (Israel)
  2. Raymond and Berverly Sackler School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel)
Publication Date:
OSTI Identifier:
22121847
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 772; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ELECTRONS; EMISSION; LIMITING VALUES; MAGNETIC FIELDS; MATHEMATICAL SOLUTIONS; MINIMIZATION; RELATIVISTIC RANGE; SELF-ABSORPTION; SPHERICAL CONFIGURATION; SYMMETRY; SYNCHROTRON RADIATION SOURCES