A near-IR study of the host galaxies of 2Jy radio sources at 0.03 < z < 0.5: I - the data

TL;DR

This study uses near-infrared imaging to analyze the morphology and structural parameters of host galaxies of 2Jy radio sources at moderate redshifts, revealing that most are massive ellipticals with some showing signs of mergers or disturbances.

Contribution

First detailed near-IR morphological analysis of 2Jy radio galaxy hosts at 0.03<z<0.5 using GALFIT, highlighting galaxy types, sizes, and merger activity.

Findings

Most hosts are massive ellipticals with high Sersic indices.

Approximately half show signs of mergers or disturbances.

Measured galaxy sizes align with previous imaging studies.

Abstract

We present the results of a program of K- and Ks-band imaging of a sample of 2Jy radio galaxies with redshifts 0.03 < z < 0.5, for which the host galaxy morphologies and structural parameters (effective radius, Sersic index and unresolved nuclear point source contribution) have been determined using GALFIT. Two-thirds of our sample are best modelled as being hosted by massive elliptical galaxies with Sersic indices of n=4-6, with the remainder being better suited either by a mixture of morphological components (usually a bulge plus a small, less luminous, disk component) or by more disky galaxy models with n=1-2. Our measured galaxy sizes are generally in very good agreement with other imaging programs, both space- and ground-based. We also determine a slightly higher average nuclear point source contribution than similar HST-based programs. This is due to our inability to separate the AGN emission from compact circum-nuclear stellar emission, but does not bias our modelling of the remainder of the host galaxies and our results remain robust. We also observe that roughly half of the objects in our sample are either undergoing major or minor merger activity or are clearly morphologically disturbed.