Local alignments of parsec-scale AGN radiojets

Abstract

Context. Coherence in the characteristics of neighboring sources in 2D and 3D space may suggest the existence of large-scale cosmic structures, which are useful for cosmological studies. Numerous works have been conducted to detect such features in global scales as well as in confined areas of the sky. However, results are often contradictory and their interpretation remains controversial.Aims. We investigate the potential alignment of parsec-scale radio jets in localized regions of the coordinates-redshift space. Methods. We use data from the Astrogeo VLBI FITS image database to deduce jet directions of radio sources. We perform the search for statistical alignments between nearby sources and explore the impact of instrumental biases. Results. We unveil four regions for which the alignment between jet directions deviates from randomness at a significance level of more than 5 σ and is unlikely due to instrumental systematics. Intriguingly, their locations coincide with other known large-scale cosmic structures and/or regions of alignments. Conclusions. If the alignments found are the result of physical processes, the discovered regions may designate some of the largest structures known to date.