J/A+A/586/A98 NGC 2683 VLA C and D datacubes (Vollmer+, 2016)
The flaring HI disk of the nearby spiral galaxy NGC 2683.
Vollmer B., Nehlig F., Ibata R.
<Astron. Astrophys. 586, A98 (2016)>
=2016A&A...586A..98V 2016A&A...586A..98V (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; H I data ; Radio sources
Keywords: galaxies: individual: NGC 2683 - galaxies: ISM -
galaxies: kinematics and dynamics
Abstract:
New deep VLA D array HI observations of the highly inclined nearby
spiral galaxy NGC 2683 are presented. Archival C array data were
processed and added to the new observations. To investigate the 3D
structure of the atomic gas disk, we made different 3D models for
which we produced model HI data cubes. The main ingredients of our
best-fit model are (i) a thin disk inclined by 80°; (ii) a crude
approximation of a spiral and/or bar structure by an elliptical
surface density distribution of the gas disk; (iii) a slight warp in
inclination between 10kpc≤R≤20kpc (decreasing by 10°); (iv) an
exponential flare that rises from 0.5kpc at R=9kpc to 4kpc at R=15kpc,
stays constant until R=22kpc, and decreases its height for R>22kpc;
and (v) a low surface-density gas ring with a vertical offset of
1.3kpc. The slope of NGC 2683's flare is comparable, but somewhat
steeper than those of other spiral galaxies. NGC 2683's maximum height
of the flare is also comparable to those of other galaxies. On the
other hand, a saturation of the flare is only observed in NGC 2683.
Based on the comparison between the high resolution model and
observations, we exclude the existence of an extended atomic gas halo
around the optical and thin gas disk. Under the assumption of vertical
hydrostatic equilibrium we derive the vertical velocity dispersion of
the gas. The high turbulent velocity dispersion in the flare can be
explained by energy injection by (i) supernovae; (ii)
magneto-rotational instabilities; (iii) interstellar medium stirring
by dark matter substructure; or (iv) external gas accretion. The
existence of the complex large-scale warping and asymmetries favors
external gas accretion as one of the major energy sources that drives
turbulence in the outer gas disk. We propose a scenario where this
external accretion leads to turbulent adiabatic compression that
enhances the turbulent velocity dispersion and might quench star
formation in the outer gas disk of NGC 2683.
Description:
NGC 2683 was observed in December 2009 for nine hours with the Very
Large Array in D array configuration. We used 0542+498 as flux
calibrator.
In addition, we reduced 8.5h of archival C array data.
Objects:
---------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------
08 52 41.34 +33 25 18.5 NGC 2683 = UGC 4641
---------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 123 2 List of fits datacubes
fits/* . 2 Individual datacubes
--------------------------------------------------------------------------------
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- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 30 I3 --- Nz Number of pixels along Z-axis
32- 41 A10 "date" Obs.Date Observation date
43- 53 E11.6 Hz bFreq Lower value of frequency interval
55- 65 E11.6 Hz BFreq Upper value of frequency interval
67- 73 F7.1 Hz dFreq Frequency resolution
75- 80 I6 Kibyte size Size of FITS file
82- 96 A15 --- FileName Name of FITS file, in subdirectory fits
98-123 A26 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Bernd Vollmer, bernd.vollmer(at)astro.unistra.fr
(End) Patricia Vannier [CDS] 01-Feb-2016