The ROGUE Project

Project Description

It is widely accepted that the broad range in radio powers (up to 4 decades), sizes (up to Mpc scales), and radio morphologies of jetted active galactic nuclei (AGNs) stems from the complex interplay between the jet production efficiency (linked to the properties of accretion flow around the supermassive black hole (SMBH) located at the centers of galaxies), interaction of jets with the host galaxy, and the large scale environment they reside in. While accretion onto the SMBH has been unequivocally accepted as the main source of AGN activity, it is not clear what fraction of it is channeled as kinetic energy of a jet as the majority of the optically selected galaxies and their high luminosity counterparts - quasars - do not show significant radio activity. Moreover, the energy exchange between the evolving radio source and the interstellar/intergalactic medium on small as well as large scales forms an important part of the feedback that governs the co-evolution of galaxies, central SMBH and galaxy groups/clusters over cosmological timescales. The wide contrast between the two main morphological classes of radio galaxies, i.e., Fanaroff-Riley type I and II, and the extremely large number of `young' radio galaxies as compared to the `evolved' ones is already driving the need to obtain large samples of radio galaxies in order to derive statistical inferences on the physics of radio AGN. In this regard, a reliable association of radio sources with their host galaxies is crucial for identifying the conditions responsible for the radio AGN trigger from the nuclear regions, host galaxies (i.e., positive/negative feedback), merger history, and the cluster environment). The ROGUE project aims at identifying these conditions and answering some of the pressing questions in AGN physics in a statisitical manner.

Our parent galaxy sample comprises of 662,531 galaxies obtained from the Sloan Digital Sky Survey (SDSS), Data Release (DR) 7. We use both First Images of Radio Sky at Twenty Centimetre (FIRST) and the NRAO VLA Sky Survey (NVSS) surveys at 1.4 GHz frequency to cross-match and corss-identify the radio-counterparts of optical galaxies. In the Radio sources associated with Optical Galaxies and having Unresolved or Extended morphologies (ROGUE) I. SDSS galaxies with FIRST core identifications sample, we have classified the optical and radio morphologies of the SDSS DR7 galaxies which presents a FIRST counterpart within 3 arcsec of the optical possition. This consist of 32,616 galaxies. The remaining galaxies, 629,915, which didn't not find a radio match but could still possess radio structure will be classified in ROGUE II. SDSS galaxies without FIRST core identifications sample.