J/A+A/596/A84 S4G disk galaxies stellar mass distribution (Diaz-Garcia+, 2016)
The stellar mass distribution of S4G disk galaxies and the signatures of
bar-induced secular evolution.
Diaz-Garcia S., Salo H., Laurikainen E.
<Astron. Astrophys. 596, A84 (2016)>
=2016A&A...596A..84D 2016A&A...596A..84D (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Galaxies, nearby ; Galaxies, IR ;
Galaxies, rotation ; Galaxies, photometry
Keywords: galaxies: evolution - galaxies: photometry - galaxies: statistics -
galaxies: structure - galaxies: bulges - galaxies: spiral
Abstract:
Models of galaxy formation in a cosmological framework require
observational constraints to be tested against, such as the average
stellar density profiles (and their dispersion) as a function of
fundamental galaxy properties (e.g. the total stellar mass).
Simulation models predict that the torques produced by stellar bars
efficiently redistribute the stellar and gaseous material inside the
disk, pushing it outwards or inwards depending on whether it is beyond
or inside the bar corotation resonance radius, respectively. Bars
themselves are expected to evolve, getting longer and narrower as they
trap particles from the disk and slow down their rotation speed.
We use 3.6um photometry from the Spitzer Survey of Stellar Structure
in Galaxies (S4G) to trace the stellar distribution in nearby disk
galaxies (z≈0) with total stellar masses 108.5≤M*/M☉≤1011
and mid IR Hubble types -3≤T≤10. We characterize the stellar density
profiles ({SIGMA}*), the stellar contribution to the rotation curves
(V3.6um) and the m=2 Fourier amplitudes (A2) as a function of M* and
T. We also describe the typical shapes and strengths of stellar bars
in the S4G sample and link their properties to the total stellar mass
and morphology of their host galaxy.
For 1154 S4G galaxies with disk inclinations lower than 65°, we
perform a Fourier decomposition and rescale their images to a common
frame determined by the size in physical units, by their disk
scalelength, and for 748 barred galaxies by both the length and
orientation of their bars. We stack the resized density profiles and
images to obtain statistically representative average stellar disks
and bars in bins of M* and T. Based on the radial force profiles of
individual galaxies we calculate the mean stellar contribution to the
circular velocity. We also calculate average A2 profiles, where the
radius is normalized to R25.5. Furthermore, we infer the gravitational
potentials from the synthetic bars to obtain the tangential-to-radial
force ratio (QT) and A2 profiles in the different bins. We also apply
ellipse fitting to quantitatively characterize the shape of the bar
stacks.
For M*≥109M☉, we find a significant difference in the stellar
density profiles of barred and non-barred systems: (i) disks in barred
galaxies show larger scalelengths (hR) and fainter extrapolated
central surface brightnesses ({SIGMA}0), (ii) the mean surface
brightness profiles ({SIGMA}*) of barred and non-barred galaxies
intersect each other slightly beyond the mean bar length, most likely
at the bar corotation, and (iii) the central mass concentration of
barred galaxies is larger (by almost a factor 2 when T≤5) than in
their non-barred counterparts. The averaged {SIGMA}* profiles follow
an exponential slope down to at least ∼10M☉/pc2, which is the
typical depth beyond which the sample coverage in the radial direction
starts to drop. Central mass concentrations in massive systems
(≥1010M☉) are substantially larger than in fainter galaxies,
and their prominence scales with T. This segregation also manifests in
the inner slope of the mean stellar component of the circular
velocity: lenticular (S0) galaxies present the most sharply rising
V3.6um . Based on the analysis of bar stacks, we show that early- and
intermediate-type spirals (0≤T<5) have intrinsically narrower bars
compared to later types and S0s, whose bars are oval-shaped. We show a
clear agreement between galaxy family and quantitative estimates of
bar strength. In early- and intermediate-type spirals, A2 is larger
within and beyond the typical bar region among barred galaxies,
compared to the non-barred subsample. Strongly barred systems also
tend to have larger A2 amplitudes at all radii than their weakly
barred counterparts.
Using near-IR wavelengths (S4G 3.6um), we provide observational
constraints for galaxy formation models to be checked against. In
particular, we calculate the mean stellar density profiles, and the
disk(+bulge) component of the rotation curve (and their dispersion) in
bins of M* and T. We find evidence for bar-induced secular evolution
of disk galaxies, in terms of disk spreading and enhanced central mass
concentration. We also obtain average bars (2-D), and we show that
bars hosted by early-type galaxies are more centrally concentrated and
have larger density amplitudes than their late-type counterparts.
Description:
We provide the tabulated radial profiles of mean stellar mass density
in bins of total stellar mass (M*, from Munoz-Mateos et al.,
2015ApJS..219....3M 2015ApJS..219....3M) and Hubble stage (T, from Buta et al., 2015, Cat.
J/ApJS/217/32). We used the 3.6um imaging for the non-highly inclined
galaxies (i<65° in Salo et al., 2015, Cat. J/ApJS/219/4) in the
Spitzer Survey of Stellar Structure in Galaxies (Sheth et al., 2010,
Cat. J/PASP/122/1397). We also provide the averaged stellar
contribution to the circular velocity, computed from the radial force
profiles of individual galaxies (from Diaz-Garcia et al.,
2016A&A...587A.160D 2016A&A...587A.160D).
Besides, we provide the FITS files of the bar synthetic images (2D)
obtained by stacking images rescaled to a common frame determined by
the bar parameters (from Herrera-Endoqui et al., 2015A&A...582A..86H 2015A&A...582A..86H)
in bins of M*, T, and galaxy family (from Buta et al. 2015). For the
bar stacks, we also tabulate the azimuthally averaged luminosity
profiles, the tangential-to-radial forces (Qt), the m=2,4 Fourier
amplitudes (A2,A4), and the radial profiles of ellipticity and b4
parameter.
The fits files (.fit) of the bar stacks, in units of flux (MJy/sr).
The pixel size is 0.02 x rbar, where rbar refers to the bar radius.
The images are cut at a radius of 3 x rbar.
In every folder, the terminology used to label the ".dat" and ".fit"
files, in relation to their content, is the following:
a) The term "starmass" is used when the binning of the sample was
based on the total stellar mass of the galaxy, from Munoz-Mateos et
al. (2015ApJS..219....3M 2015ApJS..219....3M). We indicate the common logarithm of the
boundaries: (8.5,9.9.5,10,10.5,11).
b) The term "ttype" is used when the binning of the sample was based
on the Hubble stage of the galaxy (-3,0,3,5,8,11), from Buta et al.
(2015, Cat. J/ApJS/217/32)
c) The term "family" is used when the binning of the sample was
based on the morphological family of the galaxy (AB,AB,AB,B), from
Buta et al. (2015, Cat. J/ApJS/217/32).
d) The term "hr" is used when the 1-D luminosity stacks were
obtained in a common frame determined by the scalelength of the disks
(from Salo et al., 2015, Cat. J/ApJS/219/4).
e) The term "kpc" is used when the 1-D luminosity stacks were
obtained in a common frame determined by the disk extent in physical
units (kpc).
f) The term "barred" is used when only barred galaxies are stacked
(according to Buta et al., 2015, Cat. J/ApJS/217/32).
g) The term "unbarred" is used when only non-barred galaxies are
stacked.
IDL reading:
readcol,'luminositydiskkpc/luminositydiskkpc_*.dat',Radius,$
Steldens,bSteldens,BSteldens,SuBr,bSuBr,BSuBr,Nsample,$
format='F,F,F,F,F,F,F,F',delim=' '
readcol,'luminositydiskhr/luminositydiskhr_*.dat',Radius,$
Steldens,bSteldens,BSteldens,SuBr,bSuBr,BSuB,Nsample,$
format='F,F,F,F,F,F,F,F',delim=' '
readcol,'vrotdiskkpc/vrotdiskkpc_*.dat',Radius,Vrotmean,$
Vrotmedian,Sigma,Nsample,format='F,F,F,F,F',delim=' '
readcol,'vrotdiskhr/vrotdiskhr_*.dat',Radius,Vrotmean,Vrotmedian,$
Sigma,Nsample,format='F,F,F,F,F',delim=' '
readcol,'luminositybar/barsradialluminosity*.dat',Radius,$
Steldens,SuBr,format='F,F,F',delim=' '
readcol,'forceprofbar/barsradialforces_*.dat',Radius,Qt,A2,A4,$
format='F,F,F,F',delim=' '
readcol,'ellipseprofbar/barsradialellipse_*.dat',Radius,ellipticity,b4,$
format='F,F,F',delim=' '
fitsread,'barstackfits/barstack_*.fit',image
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
data.dat 126 23 List of files in subdirectories
luminositydiskkpc/* . 19 Mean stellar density profiles and sample
dispersion (common frame defined by the
extent of the disks in kpc)
luminositydiskhr/* . 10 Mean stellar density profiles and sample
dispersion (common frame defined by the
scalelength of the disks)
vrotdiskkpc/* . 10 Mean/median stellar contribution to the
rotation curve and dispersion (common
frame defined by the disk size in kpc)
vrotdiskhr/* . 10 Mean/median stellar contribution to the
rotation curve and dispersion (common
frame defined by disk scalelength)
luminosity_bar/* . 10 Azimuthally averaged stellar density
profiles derived from the bar stacks
forceprofbar/* . 22 Gravitational torques and m=2,4 Fourier
amplitudes derived from the bar stacks
ellipseprofbar/* . 22 Radial profiles of ellipticity and b4 of
the bar stacks (ellipse fitting)
list.dat 54 22 List of fits files
barstackfits/* . 22 Fits files of the bar stacks (2D)
--------------------------------------------------------------------------------
See also:
J/PASP/122/1397 : Spitzer Survey of Stellar Structure in Galaxies (Sheth+ 2010)
J/ApJS/217/32 : S4G galaxy morphologies in the CVRHS system (Buta+, 2015)
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)
Byte-by-byte Description of file: data.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Dir Subdirectory name (1)
21- 57 A37 --- File Generic name of the file (2)
58- 65 A8 --- Bin1 First bin (3)
67- 74 A8 --- Bin2 Second bin (3)
76- 84 A9 --- Bin3 Third bin (3)
85- 93 A9 --- Bin4 Fourth bin (3)
95-103 A9 --- Bin5 Fifth bin (3)
105-113 A9 --- BinF Bin for the "family" files (3)
115-117 A3 --- F1 [ _AB] Family _AB (4)
119-120 A2 --- F2 [ AB] Family AB (4)
122-124 A3 --- F3 [ A_B] Family A_B (4)
126 A1 --- F4 [ B] Family B (4)
--------------------------------------------------------------------------------
Note (1): For the disk data,
The term "hr" is used when the 1-D luminosity stacks were
obtained in a common frame determined by the scalelength of the disks
(from Salo et al., 2015, Cat. J/ApJS/219/4).
The term "kpc" is used when the 1-D luminosity stacks were
obtained in a common frame determined by the disk extent in physical
units (kpc).
Note (2):
The term "starmass" is used when the binning of the sample was
based on the total stellar mass of the galaxy, from Munoz-Mateos et
al. (2015ApJS..219....3M 2015ApJS..219....3M). We indicate the common logarithm of the
boundaries: (8.5,9.9.5,10,10.5,11).
The term "ttype" is used when the binning of the sample was based
on the Hubble stage of the galaxy (-3,0,3,5,8,11), from Buta et al.
(2015, Cat. J/ApJS/217/32)
The term "family" is used when the binning of the sample was
based on the morphological family of the galaxy (AB,AB,AB,B), from
Buta et al. (2015, Cat. J/ApJS/217/32).
The term "barred" is used when only barred galaxies are stacked
(according to Buta et al., 2015, Cat. J/ApJS/217/32).
The term "unbarred" is used when only non-barred galaxies are stacked.
Note (3): For starmass files, logarithm of Age bin,
for ttype files, Hubble star of the galaxy bin
Note (4): Morphological family of the galaxy (AB,AB,AB,B), from
Buta et al. (2015, Cat. J/ApJS/217/32)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: luminositydiskkpc/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 6 F5.2 kpc Radius Galactocentric radius in physical units
(disk plane)
9- 15 F7.2 Msun/pc2 Steldens Mean stellar density (Stellar_density)
18- 25 F8.2 Msun/pc2 B_Steldens Mean stellar density plus sample
dispersion (Stellar_density+Sigma)
29- 35 F7.2 Msun/pc2 b_Steldens Mean stellar density minus sample
dispersion (Stellar_density-Sigma)
38- 42 F5.2 mag/arcsec2 SuBr Mean surface brightness
(Surface_brightness)
45- 49 F5.2 mag/arcsec2 B_SuBr Mean surface brightness plus sample
dispersion (Surface_brightness+Sigma)
52- 56 F5.2 mag/arcsec2 b_SuBr Mean surface brightness minus sample
dispersion (Surface_brightness-Sigma)
59- 64 F6.2 --- Nsample Number of stacked galaxies (sample
coverage in the radial direction)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: luminositydiskhr/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 6 F4.2 --- Radius Galactocentric radius normalized to the
disk scalelength (disk plane)
(1/hR unit)
9- 15 F7.2 Msun/pc+2 Steldens Mean stellar density (Stellar_density)
18- 25 F8.2 Msun/pc+2 B_Steldens Mean stellar density plus sample
dispersion (Stellar_density+Sigma)
29- 35 F7.2 Msun/pc+2 b_Steldens Mean stellar density minus sample
dispersion (Stellar_density-Sigma)
38- 42 F5.2 mag/arcsec+2 SuBr Mean surface brightness
(Surface_brightness)
45- 49 F5.2 mag/arcsec+2 B_SuBr Mean surface brightness plus sample
dispersion (Surface_brightness+Sigma)
52- 56 F5.2 mag/arcsec+2 b_SuBr Mean surface brightness minus sample
dispersion (Surface_brightness-Sigma)
59- 64 F6.2 --- Nsample Number of stacked galaxies (sample
coverage in the radial direction)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: vrotdiskkpc/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 6 F5.2 kpc Radius Galactocentric radius in physical units
(disk plane)
9- 14 F6.2 km/s Vrotmean Mean stellar contribution to the circular
velocity
17- 22 F6.2 km/s Vrotmedian Median stellar contribution to the circular
velocity
25- 29 F5.2 km/s Sigma Sample dispersion
32- 37 F6.2 --- Nsample Number of stacked galaxies (sample coverage
in the radial direction)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: vrotdiskhr/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 6 F4.2 --- Radius Galactocentric radius normalized to the disk
scalelength (disk plane) (1/hR unit)
9- 14 F6.2 km/s Vrotmean Mean stellar contribution to the circular
velocity
17- 22 F6.2 km/s Vrotmedian Median stellar contribution to the circular
velocity
25- 29 F5.2 km/s Sigma Sample dispersion
32- 37 F6.2 -- Nsample Number of stacked galaxies (sample coverage
in the radial direction)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: luminosity_bar/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.2 --- Radius Galactocentric radius normalized to the
bar length (disk plane) (1/rbar unit)
7- 13 F7.2 Msun/pc+2 Steldens Azimuthally averaged stellar density of
the bar stack
16- 20 F5.2 mag/arcsec+2 SuBr Azimuthally averaged 3.6um surface
brightness of the bar stack
--------------------------------------------------------------------------------
Byte-by-byte Description of file: forceprofbar/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.2 --- Radius Galactocentric radius normalized to the bar
length (disk plane) (1/rbar unit)
7- 11 F5.3 --- Qt Normalized tangential force (Qt=Ft/<Fr>)
14- 18 F5.3 --- A2 Normalized m=2 Fourier amplitude (A2=I2/I0)
21- 25 F5.3 --- A4 ?=* Normalized m=4 Fourier amplitude (A4=I4/I0)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: ellipseprofbar/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.3 --- Radius Galactocentric radius normalized to the bar
length (disk plane) (1/rbar unit)
8- 12 F5.3 --- ell Intrinsic isophotal ellipticity (1-b/a)
15- 21 F7.4 --- b4 Intrinsic isophotal b4 parameter
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Nx Number of pixels along X-axis
5- 7 I3 --- Ny Number of pixels along Y-axis
9- 11 I3 Kibyte size Size of FITS file
13- 54 A42 --- FileName Name of FITS file,
in subdirectory barstackfits
--------------------------------------------------------------------------------
Acknowledgements:
Simon Diaz Garcia, simon.diazgarcia(at)oulu.fi
References:
Buta et al., 2015ApJS..217...32B 2015ApJS..217...32B, Cat. J/ApJS/217/32
A classical morphological analysis of galaxies in the Spitzer Survey of
Stellar Structure in Galaxies (S4G)
Diaz-Garcia et al., 2016A&A...587A.160D 2016A&A...587A.160D, Cat. J/A+A/587/A160
Characterization of galactic bars from 3.6um S4G imaging
Herrera-Endoqui et al., 2015A&A...582A..86H 2015A&A...582A..86H, Cat. J/A+A/582/A86
Catalogue of the morphological features in the Spitzer Survey of Stellar
Structure in Galaxies (S4G)
Munoz-Mateos et al., 2015ApJS..219....3M 2015ApJS..219....3M
The Spitzer Survey of Stellar Structure in Galaxies (S4G): Stellar Masses,
Sizes, and Radial Profiles for 2352 Nearby Galaxies
Salo et al., 2015ApJS..219....4S 2015ApJS..219....4S, Cat. J/ApJS/219/4
The Spitzer Survey of Stellar Structure in Galaxies (S4G): Multi-component
decomposition strategies and data release
Sheth et al., 2010PASP..122.1397S 2010PASP..122.1397S, Cat. J/PASP/122/1397
The Spitzer Survey of Stellar Structure in Galaxies (S4G)
(End) S. Diaz Garcia [Univ. of Oulu, Finland], P. Vannier [CDS] 21-Aug-2016