Model for the Transient Emission from Blazars

Extract

The discovery of strong, variable gamma-ray sources identified with blazars by CGRO has motivated many theoretical investigations concerning the emission from relativistic jets, and several models of gamma-ray blazars have recently been developed (e.g., Dermer & Schlickeiser 1993; Bloom & Marscher 1993; Manneheim 1993; Sikora, et al. 1994; Blandford &; Levinson 1995). However, most of these efforts have been devoted to examine spectral properties of blazars using steady-state models, which are most suitable for exploring quiescent states. Although some progress in identifying the emission mechanisms in different types of blazars, and constraining the content and dynamics of relativistic jets on small scales has been made, it has became widely recognized that quantitative analysis of variability data is crucial for advancing our understanding of the nature of relativistic jets further. Despite recent observational efforts (e.g., Reich et al. 1993; Maraschi et al. 1994; Wagner 1996; Buckley et al. 1996; Takahashi et al. 1996; Mattox et al. 1997) to characterize the transient emission in blazars, only very few attempts have been made (see e.g., Romanova & Lovelace 1997) to model variability data using time dependent models.