Open AccessA radio study of neutral gas and dust in the radio galaxy 3C 293
Author(s) -
Beswick R.J.,
Pedlar A.,
Holloway A.J.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05024.x
Subject(s) - physics , astrophysics , dust lane , radius , astronomy , x shaped radio galaxy , galaxy , radio galaxy , position angle , active galactic nucleus , giant metrewave radio telescope , angular resolution (graph drawing) , star formation , computer security , mathematics , combinatorics , computer science
We have observed broad H i absorption in the radio galaxy 3C 293 using Multi‐Element Radio Linked Interferometric Network (MERLIN) at 0.2‐arcsec angular resolution and the Giant Meterwavelength Radio Telescope (GMRT) at arcsec resolution. Extensive H i is found in absorption across the centre of this peculiar radio galaxy, allowing a detailed study of the dynamics of the neutral gas on linear scales down to ∼160 pc. In optical depth position–velocity diagrams across the central few kpc we detect a distinct velocity gradient of 179 km s −1 arcsec −1 associated with the broad absorption. This is interpreted as a ring of neutral gas rotating around the suspected position of the active galactic nucleus (AGN). The radius of this high velocity gradient ring is found to be >0.74 arcsec (600 pc), implying an upper limit upon the enclosed mass of, assuming a near edge‐on disc with an inclination of i . The optical depth of H i is mapped across the entire central region of 3C 293 showing enhancements of a factor of 4 in the areas that are co‐spatial with dust lanes seen in Hubble Space Telescope ( HST ) imaging of this galaxy.