Speaker
Description
Blazars constitute the most extreme class of active galactic nuclei (AGN), characterized by relativistic plasma jets oriented directly along the line of sight to Earth. Their multi-wavelength emission displays violent variability across broad electromagnetic bands and diverse time scales, providing crucial probes into relativistic jet dynamics, particle acceleration efficiency, and non-thermal radiation mechanisms. Although Flat Spectrum Radio Quasars (FSRQs) and BL Lacertae objects (BL Lacs) exhibit well-documented spectral differences, the exact quantitative relationship between multi-frequency temporal metrics, light curve morphological structures, and the underlying particle dynamics driving variability remains poorly defined across uniform observational frameworks. This study presents a comprehensive, side-by-side comparative analysis combining high-energy γ-ray data from the Fermi Large Area Telescope (Fermi-LAT) with millimeter-wave radio observations from the Atacama Large Millimeter/submillimeter Array (ALMA). A target sample of six blazars, comprising four FSRQs (3C 273, 3C 279, 3C 454.3, and NRAO 530) and two BL Lacs (OJ 287 and PKS 1749+096), was selected from the 4LAC-DR4, FL16Y, and ALMA source catalogs. Light curves in the 0.1–300 GeV and 85–373 GHz energy ranges spanning approximately 16 years of Fermi-LAT observations across 3-day, 7-day, and 30-day temporal cadences as well as complementary 14-years of high-cadence millimeter-wave datasets from ALMA were analyzed. A suite of statistical variability metrics is computed, and flare properties such as duration, peak amplitude, and rise/decay symmetry are measured. Two-sample Kolmogorov-Smirnov statistical tests are applied to evaluate the significance of metric divergence between FSRQs and BL Lacs across both wavebands and all time-binning scales.
Ultimately, this research establishes a synchronized multi-wavelength observational baseline for blazar light-curve variability, potentially providing constraints on jet physics and emission geometry while serving as valuable input for future long-term blazar monitoring programs with ground-based facilities, including the High Energy Stereoscopic System (H.E.S.S.) and the upcoming Africa Millimetre Telescope (AMT) in Namibia.