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arXiv · 2503.10811

A FLASH on Blazars: Capturing the Radio Realm of 4FGL Blazars with SKAO Pathfinders

Meriem Behiri·Elizabeth Mahony·Elaine Sadler·Emily Kerrison·Alberto Traina·MariaVittoria Zanchettin·Vincenzo Galluzzi·Andrea Lapi·Marcella Massardi
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Abstract

This work investigates the multi-wavelength properties of 165 4FGL blazars from the Fermi-LAT fourth source catalogue, looking for with counterparts in the Australian SKA Pathfinder (ASKAP) First Large Absorption Survey in HI (FLASH) continuum. Using high-resolution data from FLASH and complementary radio datasets, combined with archival Atacama Large Millimeter Array (ALMA) observations, we perform detailed spectral energy distribution (SED) analyses across cm-to-mm wavelengths. Our findings reveal that most blazars exhibit re-triggered peaked spectra, indicative of emission dominated by a single emitting region. Additionally, we identify strong correlations between radio and gamma-ray luminosities, highlighting the significant role of relativistic jets in these active galactic nuclei. The inclusion of spectroscopic redshifts from Sloan Digital Sky Survey (SDSS) and Gaia enables a comprehensive analysis of the evolutionary trends and physical characteristics of the sources. Furthermore, we report a tight Radio-X-ray Correlation for Flat Spectrum Radio Quasars, contrasting with the more scattered behaviour observed in BL-Lacs, reflecting their distinct accretion and jet-driving mechanisms. These results provide critical insights into the physics of blazars and their environments, paving the way for future studies with next-generation facilities like the SKA Observatory (SKAO) for radio observations and Cherenkov Telescope Array for gamma-ray studies.

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Meriem Behiri, Elizabeth Mahony, Elaine Sadler, Emily Kerrison, Alberto Traina, MariaVittoria Zanchettin, Vincenzo Galluzzi, Andrea Lapi, Marcella Massardi. 2025-09-11. A FLASH on Blazars: Capturing the Radio Realm of 4FGL Blazars with SKAO Pathfinders. https://doi.org/10.1051/0004-6361%2F202554523

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