On the environments of giant radio galaxies

We test the hypothesis that environments play a key role in enabling the growth of enormous radio structures spanning more than 700 kpc, an extreme population of radio galaxies called giant radio galaxies (GRGs). To achieve this, we explore the relationships between the occurrence of GRGs and the number density of surrounding galaxies as well as the GRG locations towards large-scale structures by making use of a homogeneous sample of $\sim$100 GRGs detected from the LOFAR Two-metre Sky Survey in combination with (1) photometric galaxies from the DESI Legacy Imaging Surveys and (2) a large-scale filament catalog from the Sloan Digital Sky Survey. We probe the distributions of satellite galaxies around GRGs and the control samples, consisting of galaxies with optical colors and luminosity matched to the properties of the GRG host galaxies. Our results show that the properties of satellites around GRGs are consistent with that around the two control samples. Additionally, the properties of satellite galaxies depend on neither their relative positions to the radio jet/lobe structures nor the sizes of GRGs. We also find that the locations of GRGs and the control samples with respect to the nearby large-scale structures are consistent with each other. These results demonstrate that there is no correlation between the GRG properties and their environments traced by stars, indicating that galaxy environments play little role on the origins of GRGs. Finally, regarding radio feedback, we show that the fraction of blue satellites does not correlate with the GRG properties, suggesting that the radio jets have minimal influence on the nature of their surrounding galaxies.