Atomic and molecular gas in the merger galaxy NGC1316 (Fornax A) and its environment

We present and interpret observations of atomic and molecular gas toward the southern elliptical galaxy NGC1316 (FornaxA), a strong double-lobe radio galaxy with a disturbed optical morphology exhibiting numerous shells and loops. The ¹²CO(1-0), ¹²CO(2-1) and HI observations were made with SEST and the VLA., CO emission corresponding to a molecular hydrogen mass of ~5x10⁷ M_sun was detected towards the central position as well as northwest and southeast of the nucleus in the regions of the dust patches. The origin of the gas is likely external and due to accretion of one or several small gas rich galaxies. No HI was detected toward NGC1316 itself but 2x10⁷ M_sun of atomic gas was found toward the the giant HII region discovered by Schweizer (1980) located 6'.7 (or 36.2kpc) from the nucleus. The HI distributions and kinematics of the two nearby spiral companions of NGC1316, NGC1317 (a barred galaxy to its north), and NGC1310 (to the west west) could be studies. Both galaxies have usually small HII disks that may have been affected by ram-pressure stripping.