TY - JOUR
T1 - Properties of the molecular gas in the fast outflow in the Seyfert galaxy IC 5063
AU - Oosterloo, Tom
AU - Raymond Oonk, J. B.
AU - Morganti, Raffaella
AU - Combes, Françoise
AU - Dasyra, Kalliopi
AU - Salomé, Philippe
AU - Vlahakis, Nektarios
AU - Tadhunter, Clive
PY - 2017/12/1
Y1 - 2017/12/1
N2 - We present a detailed study of the properties of the molecular gas in
the fast outflow driven by the active galactic nucleus (AGN) in the
nearby radio-loud Seyfert galaxy IC 5063. By using ALMA observations of
a number of tracers of the molecular gas (12CO(1-0),
12CO(2-1), 12CO(3-2), 13CO(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 12CO lines, as well as that of
13CO(2-1) vs. 12CO(2-1), show that the outflow is
optically thin. We estimate the mass of the molecular outflow to be at
least 1.2 × 106 M⊙ and likely to be a
factor between two and three 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 estimated to be 12
M⊙ 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 used 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 105 and 106 cm-3.
The resulting pressures are 106-107.5 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.
AB - We present a detailed study of the properties of the molecular gas in
the fast outflow driven by the active galactic nucleus (AGN) in the
nearby radio-loud Seyfert galaxy IC 5063. By using ALMA observations of
a number of tracers of the molecular gas (12CO(1-0),
12CO(2-1), 12CO(3-2), 13CO(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 12CO lines, as well as that of
13CO(2-1) vs. 12CO(2-1), show that the outflow is
optically thin. We estimate the mass of the molecular outflow to be at
least 1.2 × 106 M⊙ and likely to be a
factor between two and three 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 estimated to be 12
M⊙ 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 used 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 105 and 106 cm-3.
The resulting pressures are 106-107.5 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.
KW - galaxies: active
KW - galaxies: individual: IC 5063
KW - ISM: jets and outflows
KW - radio lines: galaxies
KW - ENVIRONMENTS
U2 - 10.1051/0004-6361/201731781
DO - 10.1051/0004-6361/201731781
M3 - Article
SN - 0004-6361
VL - 608
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
M1 - A38
ER -