J/A+A/656/A60 NGC1808 ALMA datacubes (Audibert+, 2021)
Black hole feeding and star formation in NGC 1808.
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. 656, A60 (2021)>
=2021A&A...656A..60A 2021A&A...656A..60A (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, Seyfert ; Millimetric/submm sources
Keywords: galaxies: active - galaxies: starburst -
galaxies: kinematics and dynamics - galaxies: ISM -
galaxies: nuclei - galaxies: individual: NGC 1808
Abstract:
We report on Atacama Large Millimeter Array (ALMA) observations of
CO(3-2) emission in the Seyfert2/starburst galaxy NGC 1808, at a
spatial resolution of 4pc. Our aim is to investigate the morphology
and dynamics of the gas inside the central 0.5kpc and to probe the
nuclear feeding and feedback phenomena. We discovered a nuclear spiral
of radius 1"=45pc. Within it, we found a decoupled circumnuclear
disk or molecular torus of a radius of 0.13"=6pc. The HCN(4-3)
and HCO+(4-3) and CS(7-6) dense gas line tracers were
simultaneously mapped and detected in the nuclear spiral and they
present the same misalignment in the molecular torus. At the nucleus,
the HCN/HCO+ and HCN/CS ratios indicate the presence of an active
galactic nucleus (AGN). The molecular gas shows regular rotation,
within a radius of 400pc, except for the misaligned disk inside the
nuclear spiral arms. The computations of the torques exerted on the
gas by the barred stellar potential reveal that the gas within a
radius of 100pc is feeding the nucleus on a timescale of five
rotations or on an average timescale of ∼60Myr. Some non-circular
motions are observed towards the center, corresponding to the nuclear
spiral arms. We cannot rule out that small extra kinematic
perturbations could be interpreted as a weak outflow attributed to AGN
feedback. The molecular outflow detected at ≥250pc in the NE
direction is likely due to supernovae feedback and it is connected to
the kpc-scale superwind.
Description:
We report the combined ALMA Cycle 3 and Cycle 4 observations for
NGC1808 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).
Objects:
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RA (2000) DE Designation(s)
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05 07 42.34 -37 30 47.0 NGC 1808 = ESO 305-G008
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 115 5 List of fits fits image and datacube
fits/* . 5 Individual image and datacube
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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- 42 F9.3 km/s bVRAD Velocity or lower value of velocity interval
for the datacubes
44- 50 F7.3 km/s BVRAD ? Upper value of velocity interval
for the datacubes
52- 59 F8.5 km/s dVRAD ? Velocity resolution for the datacubes
61- 66 I6 Kibyte size Size of FITS file
68- 85 A18 --- FileName Name of FITS file, in subdirectory fits
87-115 A29 --- Title Title of the FITS file
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Acknowledgements:
Anelise Audibert, anelise.audibert(at)iac.es
References:
Combes et al., Paper I 2019A&A...623A..79C 2019A&A...623A..79C
(End) Patricia Vannier [CDS] 15-Nov-2021