The parsec scale properties of low power radio loud active galactic nuclei
| Main Author: | Giroletti, Marcello |
|---|---|
| Format: | info publication-thesis Journal |
| Terbitan: |
, 2004
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/49483 |
Daftar Isi:
- The properties of BL Lac objects are absolutely amazing at all wavelengths, from the extreme brightness temperature in the radio all the way through the electromagnetic spectrum, up to their incomparable emission at TeV energy. Besides the high brightness temperatures, the radio data present evidence for significant polarization and variability, and compact component in jets are often reported to move superluminally; optical radiation is also variable and strongly polarized, lacking significant spectral features; at higher frequency, variability is even larger, and X-ray spectra present a wide range of indexes; finally, the $\gamma-$ray data from EGRET (in the MeV/GeV domain) and from the Whipple observatory (above 100 GeV, up to 10 TeV) have revealed emission of extremely energetic photons, which contribute a major amount of the total emitted energy. Most of the properties of BL Lacs can be ascribed to non-thermal processes, such as synchrotron emission and Inverse Compton scattering. Both processes require the presence of relativistic particles, possibly located in a set of "twin" jets, originating in a compact region around a supermassive black hole.