Speaker
Description
Blazars, a subclass of active galactic nuclei (AGN) with relativistic jets aligned close to our line of sight, dominate the extragalactic gamma-ray sky and are characterised by pronounced variability across the electromagnetic spectrum. Millimetre observations are particularly valuable as they probe emission regions close to the base of the jet, where high-energy activity is thought to originate. In this study, we investigate the variability properties of the blazar 3C 279 using long-term light curves from Metsähovi at 37 GHz and from ALMA Bands 3, 6, and 7 at millimetre and sub-millimetre wavelengths. A suite of time-series analysis techniques, including the Interpolated Cross-Correlation Function (ICCF), Z-transformed Discrete Correlation Function (ZDCF), JAVELIN, and PyROA, are applied to search for inter-band time delays. The results generally indicate frequency-dependent variability behaviour consistent with opacity effects in the jet, although indications of more complex emission processes are also present. Variability amplitudes are additionally characterised using the fractional variability parameter, which shows a systematic dependence on observing frequency. These findings underscore the importance of coordinated, multi-frequency millimetre monitoring for probing jet physics in blazars and highlight the potential contribution of the Africa Millimetre Telescope (AMT) to future long-term variability studies from the southern hemisphere.
| Stream | Science or Engineering |
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