S4G Catalog Definitions
Overview
The Spitzer Survey of Stellar Structure in Galaxies (S4G) is a volume, magnitude, and sizelimited survey of over 2300 nearby galaxies at 3.6 and 4.5 microns. This is an extremely deep survey reaching an unprecedented 1 sigma surface brightness limit of μ_{3.6(AB)} = 27 mag arcsec^{2}. This translates to a stellar surface density of << 1 M_{sun} pc^{2}.
The S4G Catalog provides photometry and model parameters derived from the IRAC images, as well as a link to the summary and data access page for each galaxy and a variety of quantities taken from previously published work.
S4G Images
S4G Home Page
Sheth et al. (2010)
Name  Intype  Units  Description 

object  char  Galaxy name  
ra  double  deg  Right ascension (J2000) Measured at centroid of the peak emission at 3.6 microns 
dec  double  deg  Declination (J2000) Measured at centroid of the peak emission at 3.6 microns 
sma1_25p5  double  arcsec  Semimajor axis at mu_3.6 = 25.5 AB mag/arcsec2 
PA1_25p5  double  deg  Position angle at mu_3.6 = 25.5 AB mag/arcsec2 
ellip1_25p5  double  Ellipticity (1b/a) at mu_3.6 = 25.5 AB mag/arcsec2  
sma1_26p5  double  arcsec  Semimajor axis at mu_3.6 = 26.5 AB mag/arcsec2 
PA1_26p5  double  deg  Position angle at mu_3.6 = 26.5 AB mag/arcsec2 
ellip1_26p5  double  Ellipticity (1b/a) at mu_3.6 = 26.5 AB mag/arcsec2  
sma2_25p5  double  arcsec  Semimajor axis at mu_4.5 = 25.5 AB mag/arcsec2 
PA2_25p5  double  deg  Position angle at mu_4.5 = 25.5 AB mag/arcsec2 
ellip2_25p5  double  Ellipticity (1b/a) at mu_4.5 = 25.5 AB mag/arcsec2  
sma2_26p5  double  arcsec  Semimajor axis at mu_4.5 = 26.5 AB mag/arcsec2 
PA2_26p5  double  deg  Position angle at mu_4.5 = 26.5 AB mag/arcsec2 
ellip2_26p5  double  Ellipticity (1b/a) at mu_4.5 = 26.5 AB mag/arcsec2  
mag1  double  AB  Asymptotic magnitude at 3.6 microns Growth curve using concentric ellipses with e=ellip1_25p5 and PA=PA1_25p5 
emag1  double  AB  Growthcurve fitting error in mag1 
mag2  double  AB  Asymptotic magnitude at 4.5 microns Growth curve using concentric ellipses with e=ellip2_25p5 and PA=PA2_25p5 
emag2  double  AB  Growthcurve fitting error in mag2 
sky1  double  MJy/sr  Sky level at 3.6 microns Sky measured in ~90 boxes of 1000 pixels each 
ssky1  double  MJy/sr  Local, pixeltopixel noise at 3.6 microns 
esky1  double  MJy/sr  Large scale sky noise at 3.6 microns RMS of the mean sky values among the different boxes 
sky2  double  MJy/sr  Sky level at 4.5 microns Sky measured in ~90 boxes of 1000 pixels each 
ssky2  double  MJy/sr  Local, pixeltopixel noise at 4.5 microns 
esky2  double  MJy/sr  Large scale sky noise at 4.5 microns RMS of the mean sky values among the different boxes 
c31_1  double  r75/r25 concentration index at 3.6 microns Measured from growth curve with e=ellip1_25p5 and PA=PA1_25p5 

c42_1  double  5*log10(r80/r20) concentration index at 3.6 microns Measured from growth curve with e=ellip1_25p5 and PA=PA1_25p5 

c31_2  double  r75/r25 concentration index at 4.5 microns Measured from growth curve with e=ellip2_25p5 and PA=PA2_25p5 

c42_2  double  5*log10(r80/r20) concentration index at 4.5 microns Measured from growth curve with e=ellip2_25p5 and PA=PA2_25p5 

Mabs1  double  AB  Absolute magnitude at 3.6 microns From mag1, using dmean when available, vvir & H_{0}=71 otherwise 
Mabs2  double  AB  Absolute magnitude at 4.5 microns From mag2, using dmean when available, vvir & H_{0}=71 otherwise 
Mstar  double  Msun  log10(stellar mass) Using Mabs1 and Mabs2 in the calibration of Eskew et al. (2012) 
dmean  double  Mpc  Mean redshiftindependent distance From NED 
dstd  double  Mpc  Standard deviation of all redshiftindenpendent distances From NED 
dmin  double  Mpc  Minimum redshiftindependent distance From NED 
dmax  double  Mpc  Maximum redshiftindependent distance From NED 
dmed  double  Mpc  Median redshiftindependent distance From NED 
type  char  t  Optical Hubble type From Leda 
bar  char  Bar presence ("B"). NULL does not necessarily mean unbarred! From Leda 

ring  char  Ring presence ("R"). NULL does not necessarily mean no ring! From Leda 

multiple  char  Multiple system ("M") From Leda 

compactness  char  C=Compact. D=Difusse. NULL just means not classified! From Leda 

t  double  Morphological type code From Leda 

e_t  double  Error on t From Leda 

lc  double  Luminosity class From Leda 

e_lc  double  Error on lc From Leda 

logd25  double  0.1arcmin  log10 of apparent diameter (d25 in 0.1') From Leda 
e_logd25  double  Error on logd25 From Leda 

logr25  double  log10 of axis ratio (major axis/minor axis) From Leda 

e_logr25  double  Error on logr25 From Leda 

pa  double  deg  Major axis position angle at mu_B = 25 mag/arcsec2 From Leda 
brief  double  mag/arcsec2  Mean effective surface brightness in the B band From Leda 
e_brief  double  mag/arcsec2  Error on brief From Leda 
bt  double  mag  Total Bmagnitude From Leda 
e_bt  double  mag  Error on bt From Leda 
it  double  mag  Total Imagnitude From Leda 
e_it  double  mag  Error on it From Leda 
ubt  double  mag  Total UB color From Leda 
bvt  double  mag  Total BV color From Leda 
ube  double  mag  Effective UB color From Leda 
bve  double  mag  Effective BV color From Leda 
vmaxg  double  km/s  Apparent maximum rotation velocity of gas From Leda 
e_vmaxg  double  km/s  Error on vmaxg From Leda 
vdis  double  km/s  Central velocity dispersion From Leda 
e_vdis  double  km/s  Error on vdis From Leda 
mg2  double  mag  Central Mg2 Lick index From Leda 
e_mg2  double  mag  Error on mg2 From Leda 
m21  double  mag  21cm line flux in magnitude (see definition in text) From Leda 
e_m21  double  mag  Error on m21 From Leda 
mfir  double  mag  Far infrared magnitude (see definition in text) From Leda 
vrad  double  km/s  Heliocentric radial velocity from radio measurement From Leda 
e_vrad  double  km/s  Error on vrad From Leda 
vopt  double  km/s  Heliocentric radial velocity from optical measurement From Leda 
e_vopt  double  km/s  Error on vopt From Leda 
v  double  km/s  Mean heliocentric radial velocity From Leda 
e_v  double  km/s  Error on v From Leda 
ag  double  mag  Galactic extinction in B magnitude From Leda 
ai  double  mag  Extinction due to inclination in B magnitude From Leda 
incl  double  deg  Inclination between line of sight and polar axis From Leda 
a21  double  mag  21cm self absorption in magnitude From Leda 
lambda  double  Luminosity index From Leda 

logdc  double  0.1arcmin  log10 of apparent corrected diameter (dc in 0.1') From Leda 
btc  double  mag  Total apparent corrected Bmagnitude From Leda 
ubtc  double  mag  Total apparent corrected UB color From Leda 
bvtc  double  mag  Total apparent corrected BV color From Leda 
bri25  double  mag/arcsec2  Mean surface brightness within isophote 25 From Leda 
vrot  double  km/s  Maximum velocity rotation From Leda 
e_vrot  double  km/s  Error on vrot From Leda 
m21c  double  mag  Corrected 21cm line flux in magnitude (see text) From Leda 
hic  double  mag  21cm index btm21c in magnitude From Leda 
vlg  double  km/s  Radial velocity with respect to the Local Group From Leda 
vgsr  double  km/s  Radial velocity with respect to the GSR From Leda 
vvir  double  km/s  Radial velocity corrected for Virgocentric infall From Leda 
v3k  double  km/s  Radial velocity with respect to the CMB radiation From Leda 
modz  double  mag  Redshift distance modulus From Leda 
mod0  double  mag  True distance modulus (from parameters) From Leda 
mabs  double  mag  Absolute Bmagnitude From Leda 
summary  char  Summary and data access 