We present a detailed study of the properties of the molecular gas in the fast AGN-driven outflow in the nearby radio-loud Seyfert galaxy IC 5063 .
By using ALMA observations of a number of tracers of the molecular gas ( ^ { 12 } CO ( 1-0 ) , ^ { 12 } CO ( 2-1 ) , ^ { 12 } CO ( 3-2 ) , ^ { 13 } CO ( 2-1 ) and HCO ^ { + } ( 4-3 ) ) , we map the differences in excitation , density and temperature of the gas as function of position and kinematics .
The results show that in the immediate vicinity of the radio jet , a fast outflow , with velocities up to 800 km s ^ { -1 } , is occurring of which the gas has high excitation with excitation temperatures in the range 30–55 K , demonstrating the direct impact of the jet on the ISM .
The relative brightness of the ^ { 12 } CO lines , as well as that of ^ { 13 } CO ( 2-1 ) vs ^ { 12 } CO ( 2-1 ) , show that the outflow is optically thin .
We estimate the mass of the molecular outflow to be at least 1.2 \times 10 ^ { 6 } M _ { \odot } and likely to be a factor 2–3 larger than this value .
This is similar to that of the outflow of atomic gas , but much larger than that of the ionised outflow , showing that the outflow in IC 5063 is dominated by cold gas .
The total mass outflow rate we estimate to be \sim 12 M _ { \odot } yr ^ { -1 } .
The mass of the outflow is much smaller than the total gas mass of the ISM of IC 5063 .
Therefore , although the influence of the AGN and its radio jet is very significant in the inner regions of IC 5063 , globally speaking the impact will be very modest . We use RADEX non-LTE modelling to explore the physical conditions of the molecular gas in the outflow .
Models with the outflowing gas being quite clumpy give the most consistent results and our preferred solutions have kinetic temperatures in the range 20–100 K and densities between 10 ^ { 5 } and 10 ^ { 6 } cm ^ { -3 } .
The resulting pressures are 10 ^ { 6 } – 10 ^ { 7.5 } K cm ^ { -3 } , about two orders of magnitude higher than in the outer quiescent disk .
The highest densities and temperatures are found in the regions with the fastest outflow . The results strongly suggest that the outflow in IC 5063 is driven by the radio plasma jet expanding into a clumpy gaseous medium and creating a cocoon of ( shocked ) gas which is pushed away from the jet axis resulting in a lateral outflow , very similar to what is predicted by numerical simulations .