Taking snapshots of the jet-ISM interplay: The case of PKS0023-26
  We present high angular resolution ALMA CO(2-1) and 1.7 mm continuum
observations of the far-infrared-bright galaxy PKS0023-26, which hosts a young
radio source and a luminous optical AGN. Although young, the powerful radio
source has grown to a size of a few kpc, making it capable of affecting the ISM
of the host galaxy. We detect an extended distribution of molecular gas with a
mass between 0.3 and 3x10^10 Msun, depending on the CO conversion factor. The
gas has a maximum extent of ~24 kpc and is distributed asymmetrically wrt the
radio galaxy. Overall, the observed properties are reminiscent of molecular
structures observed in some galaxy clusters. However, in the inner few kpc, the
kinematics of the gas appears to be affected by the radio source. In the
central regions we observe the brightest emission and the broadest profiles
(FWZI ~ 500 km/s), which indicate a direct interaction of the jet with dense
clouds. On larger scales, the molecular gas appears to avoid the radio lobes
and gas with smaller velocity dispersion (FWZI ~350 km/s) is observed around
the them. There, the gas appears to be affected by the expanding cocoon
surrounding the radio source, dispersing and heating preexisting molecular
clouds. The data suggest that the mode of coupling between radio jets and ISM
changes from an outflowing phase in the inner regions to a maintenance phase at
larger radii. This reveals that on galaxy scales the impact of the AGN is not
limited to outflows. With a star-formation rate of 25 Msun/yr, PKS0023-26 is
located on the SFR-M* relation for star forming galaxies. The AGN does not
appear to have, at present, a major impact on the overall level of star
formation of the host galaxy. However, as the jet and lobes expand throughout
the galaxy, they will carry enough energy to prevent further gas cooling and/or
to inject turbulence and affect future star formation.
