Low-frequency radio surveys allow in-depth studies and new analyses of classes of sources previously known and characterised only in other bands .
In recent years , low radio frequency observations of blazars have been available thanks to new surveys , such as the GaLactic and Extragalactic All-sky MWA Survey ( GLEAM ) .
We search for gamma-ray blazars in a low frequency ( \nu < 240 MHz ) survey , to characterise the spectral properties of the spatial components .
We cross-correlate GLEAM with the fourth catalogue of active galactic nuclei ( 4LAC ) detected by the Fermi satellite .
This improves over previous works using a low frequency catalogue that is wider , deeper , with a better spectral coverage and the latest and most sensitive gamma-ray source list.In comparison to the previous study based on the commissioning survey , the detection rate increased from 35 % to 70 % .
We include Australia Telescope 20 GHz ( AT20G ) Survey data to extract high-frequency high-angular resolution information on the radio cores of blazars .
We find low radio frequency counterparts for 1274 out of 1827 blazars in the 72-231 MHz range .
Blazars have flat spectrum at \sim 100 MHz regime , with a mean spectral index \alpha = -0.44 \pm 0.01 ( assuming S _ { \nu } \propto \nu ^ { \alpha } ) .
Low synchrotron peaked objects have a flatter spectrum than high synchrotron peaked objects .
Low frequency radio and gamma-ray emission show a significant but scattered correlation .
The ratio between lobe and core radio emission in gamma-ray blazars is smaller than previously estimated .