J/A+A/632/A33 NGC 613 ALMA datacubes (Audibert+, 2019)
ALMA captures feeding and feedback from the active galactic nucleus in NGC 613.
Audibert A., Combes F., Garcia-Burillo S., Hunt L., Eckart A., Aalto S.,
Casasola V., Boone F., Krips M., Viti S., Muller S., Dasyra K.,
van der Werf P., Martin S.
<Astron. Astrophys. 632, A33 (2019)>
=2019A&A...632A..33A 2019A&A...632A..33A (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Interstellar medium
Keywords: galaxies: active - galaxies: kinematics and dynamics -
submillimeter: ISM - ISM: jets and outflows -
galaxies: evolution - galaxies: individual: NGC 613
Abstract:
We report ALMA observations of CO(3-2) emission in the Seyfert/nuclear
starburst galaxy NGC613, at a spatial resolution of 17pc, as part of
our NUclei of GAlaxies (NUGA) sample. Our aim is to investigate the
morphology and dynamics of the gas inside the central kiloparsec, and
to probe nuclear fueling and feedback phenomena. The morphology of
CO(3-2) line emission reveals a two arm trailing nuclear spiral at
r≲100pc and a circumnuclear ring at a radius of ∼350pc that is
coincident with the star-forming ring seen in the optical images.
Also, we find evidence for a filamentary structure connecting the ring
and the nuclear spiral. The ring reveals two breaks into two winding
spiral arms corresponding to the dust lanes in the optical images. The
molecular gas in the galaxy disk is in a remarkably regular rotation,
however the kinematics in the nuclear region are very skewed. The
nuclear spectrum of CO and dense gas tracers HCN(4-3), HCO+(4-3),
and CS(7-6) show broad wings up to 300km/s, associated with a
molecular outflow emanating from the nucleus (r∼25pc). We derive a
molecular outflow mass Mout=2x106M[sun and a mass outflow rate
of dMout/dt=27M_[sun/yr. The molecular outflow energetics exceed
the values predicted by AGN feedback models: the kinetic power of the
outflow corresponds to PK,out=20%LAGN and the momentum rate is
dMout/dt*v∼400LAGN/c. The outflow is mainly boosted by the AGN
through entrainment by the radio jet, but given the weak nuclear
activity of NGC613, we might be witnessing a fossil outflow resulting
from a previously strong AGN that has now faded. Furthermore, the
nuclear trailing spiral observed in CO emission is inside the inner
Lindblad resonance ring of the bar. We compute the gravitational
torques exerted in the gas to estimate the efficiency of the angular
momentum exchange. The gravity torques are negative from 25 to 100pc
and the gas loses its angular momentum in a rotation period, providing
evidence for a highly efficient inflow towards the center. This
phenomenon shows that the massive central black hole has significant
dynamical influence on the gas, triggering the inflowing of molecular
gas to feed the black hole.
Description:
We report the combined ALMA Cycle 3 and Cycle 4 observations of
CO(3-2), CS(7-6), HCN(4-3), and HCO+(4-3) and continuum in band 7,
at rest frame frequencies rest of 345.8, 342.9, 354.5, 356.7, and
350GHz, respectively. The observations of the NUGA sample are
described in Paper I (Combes et al., 2019A&A...623A..79C 2019A&A...623A..79C); here we
include additional details for NGC613.
Objects:
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RA (2000) DE Designation(s)
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01 34 18.24 -29 25 06.6 NGC 613 = ESO 413-11
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 88 5 List of fits datacubes and image
fits/* . 5 Individual datacubes and image
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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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- 32 I3 --- Nz ? Number of slices for the datacubes
34- 39 F6.1 km/s bVRAD Velocity or lower value of velocity interval
for the datacubes
40- 42 I3 km/s BVRAD ? Upper value of velocity interval
for the datacubes
44- 45 I2 km/s dVRAD ? Velocity resolution for the datcubes
47- 52 I6 Kibyte size Size of FITS file
54- 63 A10 --- FileName Name of FITS file, in subdirectory fits
65- 88 A24 --- Title Title of the FITS file
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Acknowledgements:
Anelise Audibert, anelise.audibert(at)obspm.fr
References:
Combes et al., PaperI 2019A&A...623A..79C 2019A&A...623A..79C
(End) Patricia Vannier [CDS] 25-Oct-2019