J/A+A/584/A113 Gas dynamics in tidal dwarf galaxies (Lelli+, 2015)
Gas dynamics in tidal dwarf galaxies: Disc formation at z=0.
Lelli F., Duc P.-A., Brinks E., Bournaud F., McGaugh S.S., Lisenfeld U.,
Weilbacher P.M., Boquien M., Revaz Y., Braine J., Koribalski B.S.,
Belles P.-E.
<Astron. Astrophys. 584, A113 (2015)>
=2015A&A...584A.113L 2015A&A...584A.113L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio
Keywords: dark matter - galaxies: interactions - galaxies: dwarf -
galaxies: irregular - galaxies: kinematics and dynamics -
galaxies: formation
Abstract:
Tidal dwarf galaxies (TDGs) are recycled objects that form within the
collisional debris of interacting and merging galaxies. They are
expected to be devoid of non-baryonic dark matter, since they can only
form from dissipative material ejected from the discs of the
progenitor galaxies. We investigate the gas dynamics in a sample of
six bona fide TDGs around three interacting and post-interacting
systems: NGC 4694, NGC 5291, and NGC 7252 ("Atoms for Peace").
For NGC 4694 and NGC 5291, we analyse existing HI data from the Very
Large Array (VLA), while for NGC 7252 we present new HI observations
from the Jansky VLA, together with long-slit and integral-field
optical spectroscopy. For all six TDGs, the HI emission can be
described by rotating disc models. These HI discs, however, have
undergone less than a full rotation since the time of the
interaction/merger event, raising the question of whether they are in
dynamical equilibrium. Assuming that these discs are in equilibrium,
the inferred dynamical masses are consistent with the observed
baryonic masses, implying that TDGs are devoid of dark matter. This
puts constraints on putative "dark discs" (either baryonic or
non-baryonic) in the progenitor galaxies. Moreover, TDGs seem to
systematically deviate from the baryonic Tully-Fisher relation. These
results provide a challenging test for alternative theories like MOND.
Description:
HI datacubes in FITS format for 3 interacting and post-interacting
systems that contain tidal dwarf galaxies. The channel maps are in
equatorial coordinates and in units of Jy/beam. The spatial and
velocity resolutions of the datacubes are listed in Table 6 of
Lelli+2015. The observations and data reduction of NGC 7252 are
described in the paper. The cube of NGC 4694 was derived by Duc et al.
(2007A&A...475..187D 2007A&A...475..187D) using C-array VLA data from the VIVA survey
(Chung et al., 2009AJ....138.1741C 2009AJ....138.1741C). The cube of NGC 5291 was derived
by Bournaud et al. 2007, Science, 316, 1166 using multi-array VLA
observations. This cube was "cleaned" following the same procedures as
the THINGS survey (Walter et al., 2008AJ....136.2563W 2008AJ....136.2563W, Cat.
J/AJ/136/2563), which provide a rescaled cube with correct flux
densities and a non-rescaled cube with uniform noise structure (useful
for visualization purposes and kinematic studies). We provide the
flux-rescaled cube only.
Objects:
----------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------
22 20 44.76 -24 40 42.1 NGC 7252 = LEDA 68612
12 48 15.09 +10 59 01.0 NGC 4694 = LEDA 43241
13 47 24.46 -30 24 25.0 NGC 5291 = LEDA 48893
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 154 3 List of fits data cubes
fits/* . 3 Individual data cubes
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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- 22 F3.1 arcsec/pix Scale Scale of the image
24- 26 I3 --- Nx Number of pixels along X-axis
28- 30 I3 --- Ny Number of pixels along Y-axis
32- 34 I3 --- Nz Number of slices
36- 45 A10 "date" Date Observation date
47- 57 E11.6 km/s bVELO-HEL ? Lower value of velocity interval
59- 69 E11.6 km/s BVELO-HEL ? Upper value of velocity interval
71- 78 F8.5 km/s dVELO-HEL ? Velocity resolution
80- 90 E11.6 Hz bFREQ-OHEL ? Lower value of frequency interval
92-102 E11.6 Hz BFREQ-OHEL ? Upper value of frequency interval
104-108 I5 Hz dFREQ-OHEL ? Frequency resolution
110-115 I6 Kibyte size Size of FITS file
117-134 A18 --- FileName Name of FITS file, in subdirectory fits
136-154 A19 --- Title Title of the FITS file
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Acknowledgements:
Federico Lelli, lellifederico(at)gmail.com
(End) Patricia Vannier [CDS] 07-Oct-2015