skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: OBLIQUE SHOCKS AS THE ORIGIN OF RADIO TO GAMMA-RAY VARIABILITY IN ACTIVE GALACTIC NUCLEI

Journal Article · · Astrophysical Journal

The 'shock in jet' model for centimeter-waveband blazar variability is revisited, allowing for arbitrary shock orientation with respect to the jet flow direction, and both random and ordered magnetic field. It is shown that oblique shocks can explain events with swings in polarization position angle much less than the 90{sup 0} associated with transverse structures, while retaining the general characteristics of outbursts, including spectral behavior and level of peak percentage polarization. Models dominated by a force-free, minimum energy magnetic field configuration (essentially helical) display a shallow rise in percentage polarization and frequency-dependent swing in polarization position angle not in agreement with the results of single-dish monitoring observations, implying that the field is predominantly random in the quiescent state. Outbursts well explained by the 'shock in jet' model are present during {gamma}-ray flaring in several sources, supporting the idea that shock events are responsible for activity from the radio to {gamma}-ray bands.

OSTI ID:
21578418
Journal Information:
Astrophysical Journal, Vol. 735, Issue 2; Other Information: DOI: 10.1088/0004-637X/735/2/81; ISSN 0004-637X
Country of Publication:
United States
Language:
English