J/A+A/587/A160 3.6um S4G Galactic bars characterization (Diaz-Garcia+, 2016)
Characterization of galactic bars from 3.6um S4G imaging.
Diaz-Garcia S., Salo H., Laurikainen E., Herrera-Endoqui M.
<Astron. Astrophys. 587, A160 (2016)>
=2016A&A...587A.160D 2016A&A...587A.160D (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs - Galaxies, nearby - Galaxies, IR -
Galaxies, rotation
Keywords: Galaxy: evolution - Galaxy: disk - Galaxy: structure
Abstract:
Stellar bars play an essential role in the secular evolution of disk
galaxies because they are responsible for the redistribution of matter
and angular momentum. Dynamical models predict that bars become
stronger and longer in time, while their rotation speed slows down.
We use the Spitzer Survey of Stellar Structure in Galaxies (S4G)
3.6um imaging to study the properties (length and strength) and
fraction of bars at z=0 over a wide range of galaxy masses
(M*~=108-1011M☉) and Hubble types (-3≤T≤10).
We calculated gravitational forces from the 3.6um images for galaxies
with a disk inclination lower than 65°. We used the maximum of the
tangential-to-radial force ratio in the bar region (Qb) as a measure
of the bar-induced perturbation strength for a sample of ∼600
barred galaxies. We also used the maximum of the normalized m=2
Fourier density amplitude (A2max) and the bar isophotal
ellipticity (ε) to characterize the bar. Bar sizes were
estimated i) visually, ii) from ellipse fitting, iii) from the radii
of the strongest torque, and iv) from the radii of the largest m=2
Fourier amplitude in the bar region. By combining our force
calculations with the HI kinematics from the literature, we estimated
the ratio of the halo-to-stellar mass (Mh/M*) within the optical disk
and by further using the universal rotation curve models, we obtained
a first-order model of the rotation curve decomposition of 1128 disk
galaxies.
We probe possible sources of uncertainty in our Qb measurements: the
assumed scale height and its radial variation, the influence of the
spiral arms torques, the effect of non-stellar emission in the bar
region, and the dilution of the bar forces by the dark matter halo
(our models imply that only ∼10% of the disks in our sample are
maximal). We find that for early- and intermediate-type disks
(-3≤T<5), the relatively modest influence of the dark matter halo
leads to a systematic reduction of the mean Qb by about 10-15%,
which is of the same order as the uncertainty associated with
estimating the vertical scale height. The halo correction on Qb
becomes important for later types, implying a reduction of ∼20-25% for
T=7-10. Whether the halo correction is included or not, the mean Qb
shows an increasing trend with T. However, the mean A2max
decreases for lower mass late-type systems. These opposing trends are
most likely related to the reduced force dilution by bulges when
moving towards later type galaxies. Nevertheless, when treated
separately, both the early- and late-type disk galaxies show a strong
positive correlation between Qb and A2max. For spirals the mean
ε∼0.5 is nearly independent of T, but it drops among S0s
(∼0.2). The Qb and ε show a relatively tight dependence, with
only a slight difference between early and late disks. For spirals,
all our bar strength indicators correlate with the bar length (scaled
to isophotal size). Late-type bars are longer than previously found in
the literature. The bar fraction shows a double-humped distribution in
the Hubble sequence (∼75% for Sab galaxies), with a local minimum at
T=4 (∼40%), and it drops for M*≲109.5-10M☉. If we use bar
identification methods based on Fourier decomposition or ellipse
fitting instead of the morphological classification, the bar fraction
decreases by ∼30-50% for late-type systems with T≥5 and correlates
with Mh/M*. Our Mh/M* ratios agree well with studies based on weak
lensing analysis, abundance matching, and halo occupation distribution
methods, under the assumption that the halo inside the optical disk
contributes roughly a constant fraction of the total halo mass (∼4%).
We find possible evidence for the growth of bars within a Hubble time,
as (1) bars in early-type galaxies show larger density amplitudes and
disk-relative sizes than their intermediate-type counterparts, and (2)
long bars are typically strong. We also observe two clearly distinct
types of bars, between early- and intermediate-type galaxies (T<5)
on one side, and the late-type systems on the other, based on the
differences in the bar properties. Most likely this distinction is
connected to the higher halo-to-stellar ratio that we observe in later
types, which affects the disk stability properties.
Description:
Here, we provide the bar strength measurements of a sample of ∼600
barred galaxies drawn from the Spitzer Survey of Stellar Structure in
Galaxies (Sheth et al., 2010, Cat. J/PASP/122/1397). Bars were
identified based on the morphological classifications by Buta et al.
(2015, Cat. J/ApJS/217/32). Besides, we provide a parameterization of
the stellar contribution to the rotation curve and an estimate to the
stellar-to-halo mass ratio within the optical radius for a sample of
1345 non-highly inclined galaxies (i<65°). The radial force
profiles and rotation curve decomposition models of each of these
galaxies are also given.
Table A1 contains fundamental parameters of the galaxies such as the
total stellar mass and distances (values for all the S4G sample are
calculated in Munoz-Mateos et al., 2015ApJS..219....3M 2015ApJS..219....3M). Besides, we
provide an estimate of the scale-heights and optical radii. We also
list the inclination-corrected HI maximum velocities, the parameters
of the stellar and halo components of the rotation curves, and the
estimates of the halo-to-stellar mass ratios within the optical disk.
In Table A2 it is given the gravitational torque parameters and radii,
with and without spiral arms and halo correction. In Table A3 it is
provided the maximum normalized Fourier amplitudes and radii (for the
m = 2, 4, 6 and 8 components) and the bar ellipticities (from
Herrera-Endoqui et al., 2015A&A...582A..86H 2015A&A...582A..86H) deprojected to the disk
plane using the orientation parameters from S4G Pipeline 4 (Salo et
al., 2015, Cat. J/ApJS/219/4). The evaluation of the gravitational
torques and m=2 Fourier amplitude at the bar radius is also listed in
both tables.
In the directory "rfp" we provide the gravitational torque radial
profiles, with and without spiral arms and halo correction, even
Fourier amplitudes and m=2 phase of 1345 non-highly inclined disk S4G
galaxies ("radialforce_profiles.dat"). Likewise, for the same
sample, in the directory "rcdm" we tabulate the rotation curve
decomposition model ("rotationcurve_decomposition.dat"), with the
stellar component inferred from the 3.6~µm imaging and the halo
component estimated using the universal rotation curve models).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 249 1345 Fundamental properties of S4G galaxies: distance,
mass distribution, velocities and stellar disk
tablea2.dat 202 576 Bar maximum gravitational torques and radii
tablea3.dat 112 587 Bar intrinsic ellipticity and parameters from
the Fourier dissection of bars
rfp/* . 1345 *Radial force profiles of 1345 non-highly
inclined disk S4G galaxies
rcdm/* . 1345 *Rotation curve decomposition model of 1345
non-highly inclined disk galaxies dimensions
--------------------------------------------------------------------------------
Note on rfp/*: Files labelled Galaxyradialforce_profiles.dat.
Note on rcdm/*: Files labelled Galaxyrotationcurve_decomposition.dat.
--------------------------------------------------------------------------------
See also:
J/PASP/122/1397 : S4G catalog Version 2 (Sheth+, 2010)
J/ApJ/772/135 : 3.6um surface brightness from S4G (Zaritsky+, 2013)
J/MNRAS/444/3015 : Morphologies of S4G galaxies (Laine+, 2014)
J/A+A/569/A91 : Optical imaging for S4G (Knapen+, 2014)
J/ApJS/219/4 : S4G pipeline 4: multi-component decompositions (Salo+, 2015)
J/A+A/582/A86 : Catalogue of features in the S4G (Herrera-Endoqui+, 2015)
J/ApJS/217/32 : S4G galaxy morphologies in the CVRHS system (Buta+, 2015)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Galaxy Galaxy identification
18- 29 I12 Msun M* ?=-999 Total stellar mass
35- 41 F7.3 Mpc Dist Distance to the galaxy
46- 51 F6.3 arcsec hz Disk scale-height
55- 61 F7.3 arcsec e_hz1 [] Uncertainty on the disk scale-height
associated with a thicker disk in
de Grijs/Speltincx relation
65- 71 F7.3 arcsec e_hz2 [] Uncertainty on the disk scale-height
associated with a thinner disk in
de Grijs/Speltincx relation
74- 81 F8.3 arcsec Ropt ?=-999.999 Estimated optical radius
84- 91 F8.3 km/s VHI ?=-999.999 Inclination-corrected HI
maximum velocity
94-101 F8.3 km/s V36max ?=-999.999 Maximum of the stellar
contribution to the rotation curve
105-111 F7.3 km/s e_V36max1 [] Uncertainty on the maximum of the
stellar contribution to the rotation
curve associated with a thicker disk in
de Grijs/Speltincx relation
116-121 F6.3 km/s e_V36max2 [] Uncertainty on the maximum of the
stellar contribution to the rotation
curve associated with a thinner disk in
de Grijs/Speltincx relation
124-131 F8.3 arcsec V36maxRad ?=-999.999 Radius of maximum velocity of
the stellar component of the rotation
curve
134-141 F8.3 arcsec e_V36maxRad1 []?=-999.999 Uncertainty on the radius of
maximum velocity of the stellar
component of the rotation curve
associated with a thicker disk in
de Grijs/Speltincx relation
144-151 F8.3 arcsec e_V36maxRad2 []?=-999.999 Uncertainty on the radius of
maximum velocity of the stellar
component of the rotation curve
associated with a thinner disk in
de Grijs/Speltincx relation
154-161 F8.3 km/s V36Ropt ?=-999.999 The stellar contribution to
the rotation curve evaluated at the
optical radius
164-171 F8.3 km/s e_V36Ropt1 []?=-999.999 Uncertainty on the stellar
contribution to the rotation curve
evaluated at the optical radius
associated with a thicker disk in
de Grijs/Speltincx relation
174-181 F8.3 km/s e_V36Ropt2 []?=-999.999 Uncertainty on the stellar
contribution to the rotation curve
evaluated at the optical radius
associated with a thinner disk in
de Grijs/Speltincx relation
184-191 F8.3 km/s/kpc dRV36 ?=-999.999 Inner slope of the stellar
component of the rotation curve
194-201 F8.3 km/s/kpc e_dRV361 []?=-999.999 Uncertainty on the inner
slope of the stellar component of the
rotation curve associated with a thicker
disk in de Grijs/Speltincx relation
204-211 F8.3 km/s/kpc e_dRV362 []?=-999.999 Uncertainty on the inner
slope of the stellar component of the
rotation curve associated with a thinner
disk in de Grijs/Speltincx relation
214-221 F8.3 kpc ahalo ?=-999.999 Halo core radius
232-239 F8.3 km/s Vinfhalo ?=-999.999 Halo velocity amplitude,
corrected to match the HI maximum
velocity
242-249 F8.3 --- Mh/M* ?=-999.999 Stellar-to-halo mass ratio
within the optical radius
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Galaxy Galaxy identification
18- 22 F5.3 --- Qb Bar maximum gravitational torque
25- 32 F8.3 --- e_Qb1 []?=-999.999 Uncertainty on the bar maximum
gravitational torque associated with a
thicker disk in de Grijs/Speltincx relation
38- 42 F5.3 --- e_Qb2 ?=-999.999 Uncertainty on the bar maximum
gravitational torque associated with a
thinner disk in de Grijs/Speltincx relation
46- 52 F7.3 arcsec RQb Bar maximum gravitational torque radius
55- 62 F8.3 arcsec e_RQb1 []?=-999.999 Uncertainty on the bar maximum
gravitational torque radius associated
with a thicker disk in
de Grijs/Speltincx relation
67- 72 F6.3 arcsec e_RQb2 []?=-999.999 Uncertainty on the bar maximum
gravitational torque radius associated
with a thinner disk in
de Grijs/Speltincx relation
75- 82 F8.3 --- Qbhcor ?=-999.999 Bar maximum gravitational torque
correcting for the dilution of the
dark halo
85- 92 F8.3 arcsec RQbhcor ?=-999.999 Bar maximum gravitational torque
radius correcting for the dilution of
the dark halo
95-102 F8.3 --- Qbbar ?=-999.999 Bar-only maximum gravitational
torque
105-112 F8.3 arcsec RQbbar ?=-999.999 Bar-only maximum gravitational
torque radius
115-122 F8.3 --- Qbbarhcor ?=-999.999 Bar-only maximum gravitational
torque correcting also for the dilution
of the dark halo
125-132 F8.3 arcsec RQbbarhcor ?=-999.999 Bar-only maximum gravitational
torque radius correcting also for the
dilution of the dark halo
135-142 F8.3 --- QbS08 ?=-999.999 Bar maximum gravitational torque
using the relation from Speltincx et al.
(2008MNRAS.383..317S 2008MNRAS.383..317S) for the disk
thickness estimation
145-152 F8.3 --- e_QbS081 []?=-999.999 Uncertainty on the bar maximum
gravitational torque associated with a
thicker disk in the relation from
Speltincx et al. (2008MNRAS.383..317S 2008MNRAS.383..317S)
155-162 F8.3 --- e_QbS082 ?=-999.999 Uncertainty on the bar maximum
gravitational torque associated with a
thinner disk in the relation from
Speltincx et al. (2008MNRAS.383..317S 2008MNRAS.383..317S)
165-172 F8.3 --- QTrbar ?=-999.999 Radial force profile evaluated
at the end of the bar
175-182 F8.3 --- e_QTrbar1 []?=-999.999 Uncertainty on the evaluation
of the radial force profile at the end of
the bar associated with a thicker disk in
de Grijs/Speltincx relation
185-192 F8.3 --- e_QTrbar2 ?=-999.999 Uncertainty on the evaluation of
the radial force profile at the end of the
bar associated with a thinner disk in
de Grijs/Speltincx relation
195-202 F8.3 --- QThcorrbar ?=-999.999 Halo-corrected radial force
profile evaluated at the end of the bar
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Galaxy Galaxy identification
15- 22 F8.3 --- Ell ?=-999.999 Bar intrinsic ellipticity
28- 32 F5.3 --- A2 ?=-999.999 Bar maximum normalized m=2
Fourier amplitude
36- 42 F7.3 arcsec RA2 ?=-999.999 Bar maximum normalized m=2
Fourier amplitude radius
45- 52 F8.3 --- A4 ?=-999.999 Bar maximum normalized m=4
Fourier amplitude
55- 62 F8.3 arcsec RA4 ?=-999.999 Bar maximum normalized m=4
Fourier amplitude radius
65- 72 F8.3 --- A6 ?=-999.999 Bar maximum normalized m=6
Fourier amplitude
75- 82 F8.3 arcsec RA6 ?=-999.999 Bar maximum normalized m=6
Fourier amplitude radius
85- 92 F8.3 --- A8 ?=-999.999 Bar maximum normalized m=8
Fourier amplitude
95-102 F8.3 arcsec RA8 ?=-999.999 Bar maximum normalized m=8
Fourier amplitude radius
105-112 F8.3 --- A2rbar ?=-999.999 Normalized m=2 Fourier amplitude
evaluated at the end of the bar
--------------------------------------------------------------------------------
Byte-by-byte Description of file: rfp/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.2 arcsec R Galactocentric radius
10- 16 F7.3 --- QT Radial profile of the normalized tangential
force
19- 26 F8.3 --- e_QT1 [] Uncertainty on the radial profile of the
normalized tangential force associated with a
thicker disk in de Grijs/Speltincx relation
29- 36 F8.3 --- e_QT2 [] Uncertainty on the radial profile of the
normalized tangential force associated with a
thinner disk in de Grijs/Speltincx relation
39- 46 F8.3 --- QThcor ?=-999.999 Halo-corrected radial profile of
the normalized tangential force
49- 56 F8.3 --- QTbar ?=-999.999 Bar-only radial profile of the
normalized tangential force
59- 66 F8.3 --- QTbarhcor ?=-999.999 Halo-corrected bar-only radial
profile of the normalized tangential force
70- 76 F7.3 --- QTS08 Radial profile of the normalized tangential
force using the relation from Speltincx et
al. (2008MNRAS.383..317S 2008MNRAS.383..317S) for the disk
thickness calculation
79- 86 F8.3 --- e_QTS081 [] Uncertainty on the radial profile of the
normalized tangential force associated with a
thicker disk in the relation from
Speltincx et al. (2008MNRAS.383..317S 2008MNRAS.383..317S)
89- 96 F8.3 --- e_QTS082 [] Uncertainty on the radial profile of the
normalized tangential force associated with a
thinner disk in the relation from
Speltincx et al. (2008MNRAS.383..317S 2008MNRAS.383..317S)
98-104 F7.2 deg phi Phase of m=2 Fourier amplitude
107-114 F8.3 --- A2 Normalized m = 2 Fourier density amplitude
117-124 F8.3 --- A4 Normalized m = 4 Fourier density amplitude
127-134 F8.3 --- A6 Normalized m = 6 Fourier density amplitude
137-144 F8.3 --- A8 Normalized m = 8 Fourier density amplitude
--------------------------------------------------------------------------------
Byte-by-byte Description of file: rcdm/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.2 arcsec R Galactocentric radius
10- 16 F7.3 km/s Vdisk Stellar component of the rotation curve
19- 26 F8.3 km/s e_Vdisk1 [] Uncertainty on the stellar component of the
rotation curve associated with a thicker
disk in de Grijs/Speltincx relation
31- 36 F6.3 km/s e_Vdisk2 [] Uncertainty on the stellar component of the
rotation curve associated with a thinner disk
in de Grijs/Speltincx relation
39- 46 F8.3 km/s Vhalo ?=-999.999 Halo component of the rotation
curve
49- 56 F8.3 km/s Vtotal ?=-999.999 Total circular velocity
--------------------------------------------------------------------------------
Acknowledgements:
Simon Diaz Garcia, Simon.DiazGarcia(at)oulu.fi
(End) S. Diaz Garcia [Univ. of Oulu, Finland], P. Vannier [CDS] 04-Dec-2015