Abstract
For the past 12 years we have been studying optical micro-variability of a sample of 15 Blazars. We summarize the results of this study and draw some basic conclusions about the characteristics of micro-variability. The intermittency, the stochastic nature, and the similar profile shapes seen in micro-variations at different times and in different objects have led us to a possible model to explain the observed micro-variations. The model is based on a strong shock propagating down a relativistic jet and encountering turbulence which causes density or magnetic field enhancements. We use the theory of Kirk, Reiger, and Mastichiadis (1998) to describe the pulse of synchrotron emission emanating from individual density enhancements energized by the shock. By fitting these “pulses” to micro-variability observations, we obtain excellent fits to actual micro-variations. The model predicts that the spectral index changes as a function of pulse duration. This effect should be observable in multi-frequency micro-variability data. We present the theoretical model, model fits of our micro-variability light curves, and preliminary multi-frequency micro-variability observations that support this model. A further test that has yet to be carried out involves observing polarization changes in different pulses.
Highlights
Micro-variations are very short-term, low amplitude variations in the optical part of the spectrum.These variations have been studied by a number of observers but no convincing model to account for the characteristics of these variations has been found
The intermittency, stochastic nature, profilemodel shapestoseen in micro-variations at different times and in the different objects haveand ledthe us similar to a possible explain the observed at different times and in different objects have led us to a possible model to explain the observed behavior
The model is based on a strong shock propagating down a relativistic jet and encountering turbulence, or turbulent eddies propagating down the jet encountering a standing shock
Summary
Micro-variations are very short-term, low amplitude variations in the optical part of the spectrum. These variations have been studied by a number of observers but no convincing model to account for the characteristics of these variations has been found. Our program at Florida International University has observed micro-variability in a sample of fifteen Blazars during 164 nights over 12 years. We define micro-variability as: “Rapid, low-amplitude non-linear variations in optical fluctuations in a single night”. The observed timescales are from a few minutes to a few hours, and amplitudes range from.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
