Y. Chandola1, S. K. Sirothia1, D. J. Saikia1,2 and Neeraj Gupta3
Abstract.
We report the results of Giant Metrewave Radio Telescope (GMRT) obser-
vations of H absorption towards the FRII radio galaxy 3C321 (J1531+2404), which
is associated with an active galaxy interacting with a companion. The absorption profile
towards the radio core is well resolved and consists three components, of which
the two prominent ones are red-shifted by 186 and 235 km s−1 relative to the optical
systemic velocity. The neutral hydrogen column density towards the core is estimated
to be N(H)=9.23×1021 (Ts/100)(fc/1.0) cm−2,
where Ts and fc are the spin temperature
and covering factor of the background source respectively. We also present radio
continuum observations of the source with both the GMRT and the Very Large Array
(VLA) in order to understand the properties of a plume of emission at an angle of ∼30°
to the source axis. This feature appears to have a steep high-frequency spectrum. The
current hotspots and jet are active and seen in X-ray emission. The spectral ages of the
lobes are <26 Myr. We discuss the possibility that the plume could be relic emission
due to an earlier cycle of activity.
Keywords: galaxies: active – galaxies: nuclei – galaxies: individual: 3C321 – radio
continuum: galaxies – radio lines: galaxies
1NCRA, TIFR, Pune University Campus, Post Bag 3, Pune 411 007, India
2Cotton College State University, Panbazar, Guwahati 781 001, Assam, India
2ASTRON, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands