J/A+A/704/A125 AGN inflow and outflow in the Circinus galaxy (Goesaert+, 2025)
Torus feeding and outflow launching in the active nucleus of the Circinus
galaxy.
Goesaert W.M., Tristram R.W.K, Impellizzeri C.M.V., Hygate A.P.S.,
Venselaar S., Wang J., Zhang Z.
<Astron. Astrophys. 704, A125 (2025)>
=2025A&A...704A.125G 2025A&A...704A.125G (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Active gal. nuclei ; Millimetric/submm sources
Keywords: galaxies: active - galaxies: ISM - galaxies: individual: Circinus -
galaxies: kinematics and dynamics - galaxies: nuclei -
galaxies: Seyfert
Abstract:
Most active galactic nuclei (AGN) are believed to be surrounded by a
dusty molecular torus on the parsec scale, which is often embedded
within a larger circumnuclear disk (CND). AGN are fuelled by the
inward transport of material through these structures and can launch
multi-phase outflows that influence the host galaxy through AGN
feedback.
We use the Circinus Galaxy as a nearby laboratory to investigate the
physical mechanisms responsible for feeding the torus and launching a
multi-phase outflow in this Seyfert-type AGN, as these mechanisms
remain poorly understood.
We analysed observations from the Atacama Large
Millimeter/submillimeter Array of the Circinus nucleus at angular
resolutions down to 13mas (0.25pc). We traced dust and the ionised
outflow using 86-665GHz continuum emission and studied the morphology
and kinematics of the molecular gas using the HCO+(3-2),
HCO+(4-3), HCN(3-2), HCN(4-3) and CO(3-2) transitions.
We find that the Circinus CND hosts molecular and dusty spiral arms,
two of which connect directly to the torus. We detect inward mass
transport along these structures and argue that the non-axisymmetric
potential generated by these arms is the mechanism responsible for
fuelling the torus. We estimate a feeding rate of 0.3-7.5M☉/yr,
implying that over 88% of the inflowing material is expelled in a
multi-phase outflow before reaching the accretion disk. The inferred
feeding time scale (tfeed,torus=120kyr-2.7Myr) suggests that
variability in AGN activity may be driven by changes in torus feeding.
On parsec scales, the ionised outflow is traced by optically thin
free-free emission. The outflow is stratified, with a slightly wider
opening angle in the molecular phase than in the dusty and ionised
components. The ionised outflow is launched or collimated by a warped
accretion disk at a radius of r∼0.16pc, and its geometry requires an
anisotropic launching mechanism.
Description:
We hereby publish our moment zero integrated flux density maps of the
Circinus AGN. This data was taken as part of the project
2018.1.00581.S which was led by the PI: Konrad R.W. Tristram. For
details about the data reduction, we refer the user to our paper.
IMPORTANT for the CO(3-2) map: As discussed in the paper, we masked
out negative values in the image cube to remove artefacts caused by
large scale emission that exceeds the maximal recoverable scale. Since
this mask causes an upward bias in the flux density, the resulting
CO(3-2) moment zero map is unsuitable for quantitative flux
measurements.
In addition to these 2D maps, we also provide an extended version of
the SED flux density measurements from table A.2 in our paper. The new
data points in this list were obtained by first convolving the maps to
some common beam size and then either measuring the continuum peak
value for the AGN or circular aperture photometry with radius 150 mas
or 100 mas. The names of the new measurements are as follows:
InstrumentALMAbandcommonbeamsizeband, so ALMAB9cb3 is band 9
continuum data which has first been convolved to have the same beam
size as band 3 before taking the photometry.
Objects:
--------------------------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------------------------
14 13 09.90 -65 20 20.4 Circinus galaxy = ESO-LV 97-0130
--------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea2.dat 112 35 SED datapoints extended list from table A.1
list.dat 165 8 List of fits images
fits/* . 8 Individual fits images
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See also:
J/A+A/549/A139 : Circinus galaxy CRIRES observations (Gnerucci+, 2013)
J/A+A/663/A35 : Circinus galaxy N-band VLTI/MATISSE images (Isbell+, 2022)
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Inst Instrument name
19- 30 E12.7 Hz Freq Frequency
32- 49 E18.13 Jy S Flux density at Freq
51- 71 F21.19 Jy e_S Flux density at Freq error
73- 81 F9.7 arcmin amaj Major beamsize
83- 88 F6.4 arcmin amin Minor beamsize
90-112 A23 --- Ref Reference (1)
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Note (1): References as follows:
Elmouttie et al. (1998) = 1998MNRAS.297.1202E 1998MNRAS.297.1202E
Prieto et al. 2004 = 2004ApJ...614..135P 2004ApJ...614..135P
Reunanen et al. 2009 = 2009hnc2.conf..289R
Tristram et al. 2007 = 2007A&A...474..837T 2007A&A...474..837T
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Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 55 A26 "datime" Obs.date Observation date
57- 61 I5 Kibyte size Size of FITS file
63-104 A42 --- FileName Name of FITS file, in subdirectory fits
106-165 A60 --- Title Title of the FITS file
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Acknowledgements:
M. Wout Goesaert, goesaert(at)strw.leidenuniv.nl
(End) Patricia Vannier [CDS] 29-Sep-2025