Alignment of Radio Galaxy Axes using FIRST Catalogue

Abstract

We study the alignment of radio galaxies axes using the FIRST catalogue. we impose several cuts in order to select the candidates which are most likely to be free of systematic bias. In our study we primarily focus on testing for alignment among sources within a certain angular separation from one another since for most sources redshift information is not available. We find a very significant effect for angular distances less than 1 degrees. The distance scale of alignment is found to be roughly 28 Mpc, in agreement with earlier estimates, assuming that these sources are dominantly at redshift of 0.8. However we are not able to entirely rule out the possibility of systematic bias in data. We also perform a full three dimensional analysis using a smaller data sample for which redshift information is available. In this case we only find a very weak signal at much larger distances.

Probing the cosmological principle using the slope of log N-log S relationship for quasars

“…Many other observations indicate a potential departure from the ΛCDM model. These include a dipole in the radio polarization offset angles [30], alignment of quasar polarization at optical frequencies at Gpc distance scales [31,32], alignment of radio polarizations [33][34][35], alignment of radio axes [36,37] and anisotropy in the Hubble constant [38]. Ref.…”

Local alignments of parsec-scale AGN radiojets

“…The lack of alignments was explained by the sparsity of this sample. Lately, Panwar et al (2020) used information from the FIRST catalogue to study possible alignments of sources with small angular separation. They searched for systematic alignments of the axes of radio galaxies at different angular scales.…”