J/A+A/561/A28 WSRT HI data cubes of the dwarf galaxy UGCA 105 (Schmidt+, 2014)
Structure and kinematics of the nearby dwarf galaxy UGCA 105.
Schmidt P., Jozsa G.I.G., Gentile G., Oh S.-H., Schuberth Y.,
Ben Bekhti N., Winkel B., Klein U.
<Astron. Astrophys. 561, A28 (2014)>
=2014A&A...561A..28S 2014A&A...561A..28S
ADC_Keywords: Galaxies, nearby ; Galaxies, radio ; Galaxies, rotation ; H I data
Keywords: galaxies: dwarf - galaxies: irregular -
galaxies: kinematics and dynamics - galaxies: structure -
dark matter - galaxies: individual: UGCA105
Abstract:
Owing to their shallow stellar potential, dwarf galaxies possess thick
gas disks, which makes them good candidates for studies of the
galactic vertical kinematical structure. We present 21cm line
observations of the isolated nearby dwarf irregular galaxy UGCA 105,
taken with the Westerbork Synthesis Radio Telescope (WSRT), and
analyse the geometry of its neutral hydrogen (HI) disk and
its kinematics. The galaxy shows a fragmented HI
distribution. It is more extended than the optical disk, and hence
allows one to determine its kinematics out to very large galacto-
centric distances. The HI kinematics and morphology are
well-ordered and symmetric for an irregular galaxy. The HI
is sufficiently extended to observe a substantial amount of
differential rotation. Moreover, UGCA 105 shows strong signatures for
the presence of a kinematically anomalous gas component. Performing
tilted-ring modelling by use of the least-squares fitting routine
TiRiFiC, we found that the HI disk of UGCA 105 has
a moderately warped and diffuse outermost part. Probing a wide range
of parameter combinations, we succeeded in modelling the data cube as
a disk with a strong vertical gradient in rotation velocity
(~-60km/s/kpc), as well as vertically increasing inwards motion
(~-70km/s/kpc) within the radius of the stellar disk. The inferred
radial gas inflow amounts to 0.06M☉/yr, which is similar to the
star formation rate of the galaxy. The observed kinematics are hence
compatible with direct or indirect accretion from the intergalactic
medium, an extreme backflow of material that has formerly been
expelled from the disk, or a combination of both.
Description:
Two HI data cubes of UGCA 105, CLEANed using a robust weighting of 0
and 0.4, respectively. Axes are RA, DEC, LSR velocity. For details,
see Table 2 of the corresponding publication.
Objects:
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RA (2000) DE Designation(s)
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05 14 15.35 +62 34 47.9 UGCA 105 = AGC 150027
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 68 2 List of datacube files
fits/* . 2 Individual datacubes in FITS format
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See also:
J/AJ/116/2246 : HII regions in UGCA 86, 92, 105 & UGC 4115 (Kingsburgh+, 1998)
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 I1 arcsec/pix Scale [4/7] Scale of the image
22- 24 I3 pix Nx [512] Number of pixels along X-axis
25 A1 --- --- [x]
26- 28 I3 pix Ny [512] Number of pixels along Y-axis
29 A1 --- --- [x]
30- 32 I3 pix Nz [82/164] Number of slices
34- 38 F5.2 km/s VHl Lower value of heliocentric velocity interval
41 A1 --- --- [/]
43- 48 F6.2 km/s VHu upper value of heliocentric velocity interval
50- 53 F4.2 km/s dVH [2.06/4.12] Resolution in heliocentric velocity
55- 68 A14 --- FileName Name of FITS file in subdirectory fits
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Acknowledgements:
Philip Schmidt, pschmidt(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 19-Nov-2013