J/ApJ/782/64 Galaxy structural parameters from 3.6um images (Kim+, 2014)
Unveiling the structure of barred galaxies at 3.6 µm with the Spitzer survey
of stellar structure in galaxies (S4G). I. Disk breaks.
Kim T., Gadotti D.A., Sheth K., Athanassoula E., Bosma A., Lee M.G.,
Madore B.F., Elmegreen B., Knapen J.H., Zaritsky D., Ho L.C., Comeron S.,
Holwerda B., Hinz J.L., Munoz-Mateos J.-C., Cisternas M., Erroz-Ferrer S.,
Buta R., Laurikainen E., Salo H., Laine J., Menendez-Delmestre K.,
Regan M.W., de Swardt B., Gil de Paz A., Seibert M., Mizusawa T.
<Astrophys. J., 782, 64 (2014)>
=2014ApJ...782...64K 2014ApJ...782...64K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, IR ; Galaxies, photometry ; Morphology
Keywords: galaxies: evolution - galaxies: formation -
galaxies: fundamental parameters - galaxies: photometry -
galaxies: spiral - galaxies: structure
Abstract:
We have performed two-dimensional multicomponent decomposition of 144
local barred spiral galaxies using 3.6µm images from the Spitzer
Survey of Stellar Structure in Galaxies. Our model fit includes up to
four components (bulge, disk, bar, and a point source) and, most
importantly, takes into account disk breaks. We find that ignoring the
disk break and using a single disk scale length in the model fit for
Type II (down-bending) disk galaxies can lead to differences of 40% in
the disk scale length, 10% in bulge-to-total luminosity ratio (B/T),
and 25% in bar-to-total luminosity ratios. We find that for galaxies
with B/T≥0.1, the break radius to bar radius, rbr/Rbar, varies
between 1 and 3, but as a function of B/T the ratio remains roughly
constant. This suggests that in bulge-dominated galaxies the disk
break is likely related to the outer Lindblad resonance of the bar and
thus moves outward as the bar grows. For galaxies with small bulges,
B/T<0.1, rbr/Rbar spans a wide range from 1 to 6. This suggests
that the mechanism that produces the break in these galaxies may be
different from that in galaxies with more massive bulges. Consistent
with previous studies, we conclude that disk breaks in galaxies with
small bulges may originate from bar resonances that may be also
coupled with the spiral arms, or be related to star formation
thresholds.
Description:
We select our samples from the Spitzer Survey of Stellar Structure in
Galaxies (S4G; Sheth et al. 2010, cat. J/PASP/122/1397).
We chose galaxies that had already been processed by the first three
S4G pipelines (Pipelines 1, 2, and 3; Sheth et al. 2010, cat.
J/PASP/122/1397) at the moment of this study (2011 November).
In brief, Pipeline processes images and provides science-ready images.
Pipeline 2 prepares mask images (to exclude foreground and background
objects) for further analysis, and Pipeline 3 derives surface
brightness profiles and total magnitudes using IRAF ellipse fits. We
excluded highly inclined (b/a<0.5), significantly disturbed, very
faint, or irregular galaxies. Galaxies were also discarded if their
images are unsuitable for decomposition due to contamination such as a
bright foreground star or significant stray light from stars in the
IRAC scattering zones. Then we chose barred galaxies from all Hubble
types from S0 to Sdm using the numerical Hubble types from Hyperleda
(Paturel et al. 2003, cat. VII/237, VII/238). The assessment of the
presence of a bar was done visually by K. Sheth, T. Kim, and B. de
Swardt. Later, we also confirmed the presence of a bar by checking the
mid-infrared classification (Buta et al. 2010, cat. J/ApJS/190/147;
Buta et al. 2015, cat. J/ApJS/217/32). A total of 144 barred galaxies
were selected that satisfy our criteria, and we list our sample in
Table1 with basic information. Table2 presents the measures of
structural parameters for all galaxies in the sample obtained from the
2D model fit with BUDDA (BUlge/disk Decomposition Analysis, de Souza
et al., 2004ApJS..153..411D 2004ApJS..153..411D; Gadotti, 2008MNRAS.384..420G 2008MNRAS.384..420G) code.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 58 144 Sample
table2.dat 127 144 Structural parameters from BUDDA image decompositions
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See also:
VII/237 : HYPERLEDA. I. Catalog of galaxies (Paturel+, 2003)
VII/238 : HYPERLEDA. II. Homogenized HI data (Paturel+, 2003)
J/ApJS/217/32 : S4G galaxy morphologies in the CVRHS system (Buta+, 2015)
J/ApJ/771/59 : Surface brightness of S4G face-on galaxies
(Munoz-Mateos+, 2013)
J/ApJS/190/147 : Mid-IR galaxy morphology from S4G (Buta+, 2010)
J/PASP/122/1397 : Spitzer Survey of Galaxy Stellar Structure (Sheth+, 2010)
J/MNRAS/393/1531 : BUDDA structural properties of galaxies (Gadotti+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Galaxy name
12- 36 A25 --- Class Mid-infrared classification (1)
38- 41 F4.1 --- MType [-2.5/9] HyperLEDA numerical morphological type
43- 47 F5.1 arcsec Rad [39/413] Radius at µ3.6µm=25.5 AB mag (2)
49- 53 F5.1 mag [3.6] [-23/-17] Total 3.6µm AB magnitude (2)
55- 58 F4.1 Mpc Dist [6/54] NED distance (3)
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Note (1): From Buta et al. 2010 (cat. J/ApJS/190/147), and Buta et al. 2015
(cat. J/ApJS/217/32).
Note (2): From S4G Pipeline 3.
Note (3): We made use of the mean redshift-independent distance from NED when
available, otherwise, the redshift-based distance.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Galaxy name
12 A1 --- N [abc] Note on Name (a, b, or c) (1)
14- 16 F3.1 --- nbul [0.6/4.4]? Bulge Sersic index
18- 21 F4.1 arcsec Reff [1.4/18.1]? Bulge effective radius
23- 26 F4.1 mag/arcsec2 mueff [16.2/21.8]? Bulge surface brightness at Reff
28- 30 I3 deg PA1 [0/178]? Bulge position angle
32- 35 F4.2 --- ell1 [0.01/0.61]? Bulge ellipticity
37- 40 F4.1 mag/arcsec2 mu0i [18.9/22.8] Central surface brightness of
inner disk
42- 45 F4.1 mag/arcsec2 mu0o [16.9/21.5]? Extrapolated central surface
brightness of outer disk
47- 51 F5.1 arcsec hin [6.9/195.5] Inner disk scale length
53- 57 F5.1 arcsec hout [7/118.3]? Outer disk scale length
59- 61 I3 arcsec Rbr [11/212]? Break radius of disk
63- 65 I3 deg PA2 [0/177] Disk position angle
67- 70 F4.2 --- ell2 [0.01/0.6] Disk ellipticity
72- 75 F4.2 --- nbar [0.15/2.75] Bar Sersic index
77- 79 I3 arcsec rbar [6/122] Projected (observed) bar length of the
semi-major axis
81- 83 I3 arcsec Rbar [9/126] Deprojected bar length
85- 87 F3.1 --- c [2.2/3.9] Boxiness parameter of the bar
(i.e. shape parameter c)
89- 91 I3 deg PA3 [1/179] Bar position angle
93- 96 F4.2 --- ell3 [0.24/0.82] Bar ellipticity
98-101 F4.2 --- B/T [0/0.53]? Fraction of total galaxy luminosity
in bulge
103-106 F4.2 --- Di/T [0.1/0.97] Fraction of total galaxy luminosity
in inner disk
108-111 F4.2 --- Do/T [0.05/0.7]? Fraction of total galaxy
luminosity in outer disk
113-116 F4.2 --- D/T [0.31/0.98] Fraction of total galaxy
luminosity in disk (i.e., the sum of inner
and outer disks)
118-121 F4.2 --- Bar/T [0.01/0.34] Fraction of total galaxy
luminosity in bar
123-127 F5.3 --- PS/T [0.001/0.032]? Fraction of total galaxy
luminosity in point source
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Note (1): The notes are described as follows:
a = Galaxies that have a lens or inner ring. Derived break radii of theses
galaxies are the lengths of lens or inner ring. Inner (outer) disk
scale lengths of these galaxies are disk scale length of disk inside
(outside) of lens or inner ring. These galaxies do not show another
break further out. See Section 4 for details;
b = Inner ring or len was modeled, but the galaxy has another break
further out;
c = Galaxies that have two breaks (TII.o + TIII). The inner break was
modeled, but these are not inner rings nor lenses.
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 02-Mar-2016