Abstract Details
| Name: Mousumi Mahato Affiliation: IUCAA, Pune Conference ID: ASI2019_314 Title : Multifrequency radio properties of Giant radio quasars using GMRT Authors and Co-Authors : Pratik Dabhade, Mousumi Mahato, Joydeep Bagchi, Madhuri Gaikwad, Huub Rottgering, Ishwar Chandra, Francoise Combes, DJ Saikia, KG Biju, Shishir Sankhyayan. Abstract Type : Oral Abstract Category : Extragalactic Astronomy Abstract : The extreme rarity and enormity (≥ 0.7 Mpc), as well as high redshift and high luminosity, have made giant radio quasars (GRQs) an unprecedented beacon to leaf through the tide of years to unveil the history of our Universe. To understand the evolutionary scheme of radio sources, eventually leading to their unification scheme, it is inevitable to understand the lifetime of jet forming activity of AGN and the stability of jets. Till date, no study of giant radio quasars has prospectively considered the spectral ageing analysis & estimation of the magnetic field. Our study for the first time focuses on multifrequency radio properties of 3 GRQs. GMRT provides high-resolution radio maps at low frequencies enabling us to perform spectral analysis (dissecting radio core, lobe, jet & backflows). Multifrequency observations provide us with information on break frequency as well as the spectral index in the significant regions under consideration from the power law spectrum. The spectral index profile gives us an idea about the equipartition energy density and magnetic field profiles (classical: 1.1 - 7.7 microgauss and revised: 1.6 - 11.6 microgauss) which along with the break frequency yield in spectral ages of the aforesaid regions. The spectral ages (classical and revised) are in the range of 30 - 83 Myr. We have also estimated the jet kinetic power of the sources (10^43 - 10^44 erg/s). The results from the numerical analysis are quite consistent with the results obtained from simulation-based analytical model (Hardcastle 2018). Apart from this, the star formation rate (SFR) of our 3 GRQs (4 - 66 Msun/yr), computed using mid-infrared (24 micrometres) luminosity comes out to be high. It gives an insight into the feedback mechanism of the most powerful AGNs in the Universe. |