J/A+A/647/A20 NGC 352 R-band image (Patsis+, 2021)
Edge-on boxes with X-features as parts of galactic bars.
NGC 352: A direct piece of observational evidence.
Patsis P.A., Xilouris E.M., Alikakos J., Athanassoula E.
<Astron. Astrophys. 647, A20 (2021)>
=2021A&A...647A..20P 2021A&A...647A..20P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry
Keywords: galaxies: bulges - galaxies: kinematics and dynamics -
galaxies: spirale - galaxies: structure
Abstract:
This paper is a contribution to the discussion about whether the
X/peanut component is part of the bar, or the bar itself.
Our goal is to present a clear-cut case of a barred-spiral galaxy in
which all structural components (i.e. the thick and thin part of the
bar and the spiral arms) can be observed in its image and their
dimensions directly measured there.
We obtained deep images of the nearby galaxy NGC 352, which has an
ideal inclination allowing us to observe all of the parts that compose
its morphology, estimate their relative sizes, and determine the
topology of the luminous matter of this galaxy. We successfully
compare our findings with the existence and the relative dimensions of
the corresponding components encountered in the disc of a GADGET
N-body model.
NGC 352 is a barred spiral galaxy with a bar of about 13 kpc radius.
Its bar has a central thick part that extends up to a distance about
5kpc from the centre of the galaxy along its major axis, while its
thickness reaches a height of 3.8kpc. Thus, the thick part of the bar
occupies the central part of the bar component, and its length is
about 40% of that of the thin bar. The branches of the X-feature are
characterised by the presence of 'hooks' at their extremities. The
profile along the major axis of the bar is characterised by the
presence of 'shoulders', the end of which is associated with local
surface brightness enhancements on the equatorial plane. A central
disc with a spiral-like feature embedded in it dominates in the
innermost 1.7kpc.
NGC 352 offers a case in which we directly observe that the X/peanut
component is unambiguously part of the bar. This boxy structure is
neither a separate bulge component nor the bar itself. The relative
extent of the peanut with respect to the bar is well inside the range
predicted in the majority of the simulated N-body bars. The hooks of
the X-feature and the local surface brightness enhancements on the
equatorial plane have their counterparts in surface density features
of models based on the orbital theory, as well as of models based on
response calculations and of fully selfconsistent N-body calculations.
Description:
The galaxy was observed in the broad (1065.6Å) R band, centred at
6349Å, with the 2.3m Aristarchos telescope at Helmos Observatory in
Greece. We used the LN2 CCD optical imaging camera e2v CCD42-40, which
had a scale of 0.314"/pixel on the re-binned to 1024x1024 pixels
field. Three sets of 9600s, 4900s, and 11200s were obtained, yielding
a total of 10200 s of observing time. Observations were made on July
21-22 and September 23, 2017.
R-band image of NGC 352, as observed with the Aristarchos telescope.
Objects:
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RA (2000) DE Designation(s)
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01 02 09.21 -04 14 43.6 NGC 352 = LEDA 3701
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 119 1 Information on the fits image
fits/* . 1 Fits 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- 33 I4 Kibyte size Size of FITS file
35- 51 A17 --- FileName Name of FITS file, in subdirectory fits
53-119 A67 --- Title Title of the FITS file
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Acknowledgements:
Panos Patsis, patsis(at)Academyofathens.gr
(End) Patricia Vannier [CDS] 25-Dec-2020