Abstract Details
| Name: Pratik Dabhade Affiliation: University of Pune Conference ID: ASI2015_411 Title : Discovery of 10 Giant radio galaxies Authors and Co-Authors : Pratik Dabhade,Madhuri Gaikwad (University of Pune) & Joydeep Bagchi (IUCAA) Abstract Type : Poster Abstract Category : Extragalactic astronomy Abstract : We present the discovery of ten new giant radio galaxies found from the The NRAO VLA Sky Survey (NVSS) which was released about 15 years ago, which signifies the importance of the survey and the fact that its far from becoming obsolete. All the sources are FR II radio galaxies with a projected linear size greater than 1 Mpc. GRGs are extremely useful laboratories for astrophysical studies and based on our current understanding and observations, they are the single largest objects in the universe.GRGs are rare among the entire population of radio galaxies (RGs) and their physical evolution is not well understood so far.These radio sources host a active galactic nuclei (AGN) at the center. It is believed that the central engine in the AGN is responsible for the production of bipolar relativistic jets. Since the GRGs are known expand to such enormous large sizes, they are thought to be the last stop of radio galaxy evolution and hence help us provide important constraints on the various evolutionary models. For the existence of the lobes at greater distances a working surface is essential or in other words some medium is necessary for the lobes to formed. The lobes of these radio sources are capable of compressing cold gas clumps and can set in motion ideal conditions for star or even dwarf galaxy formation, they can also contribute sigificantly in transporting gas from a host galaxy to large distances and seed the intergalactic medium (IGM) with magnetic fields. These objects are also most likely the candidates for accelerating particles to high energies. We also present the computed radio and the infrared luminosities of all the GRGs.The mass of the central black hole of GRGs has been determined using the M-sigma relation and K band bulge luminosity. The optical and radio observations clearly show that two of our new GRGs lie in a dense cluster medium which emphasizes that the environment does not play a major role in their exceptional large sizes. We have shown for first time the classification of GRGs into QSOs, LERGs, HERGs etc using the WISE color color plot. A more thorough radio studies of these GRGs at lower frequencies are neccesary to obtain its spectral index and map the diffused emission. |