S4G Catalog Definitions

Overview

The Spitzer Survey of Stellar Structure in Galaxies (S4G) is a volume-, magnitude-, and size-limited 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 μ3.6(AB) = 27 mag arcsec-2. This translates to a stellar surface density of << 1 Msun 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 Semi-major 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 (1-b/a) at mu_3.6 = 25.5 AB mag/arcsec2
sma1_26p5 double arcsec Semi-major 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 (1-b/a) at mu_3.6 = 26.5 AB mag/arcsec2
sma2_25p5 double arcsec Semi-major 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 (1-b/a) at mu_4.5 = 25.5 AB mag/arcsec2
sma2_26p5 double arcsec Semi-major 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 (1-b/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 Growth-curve 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 Growth-curve 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, pixel-to-pixel 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, pixel-to-pixel 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 & H0=71 otherwise
Mabs2 double AB Absolute magnitude at 4.5 microns
From mag2, using dmean when available, vvir & H0=71 otherwise
Mstar double Msun log10(stellar mass)
Using Mabs1 and Mabs2 in the calibration of Eskew et al. (2012)
dmean double Mpc Mean redshift-independent distance
From NED
dstd double Mpc Standard deviation of all redshift-indenpendent distances
From NED
dmin double Mpc Minimum redshift-independent distance
From NED
dmax double Mpc Maximum redshift-independent distance
From NED
dmed double Mpc Median redshift-independent 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 B-magnitude
From Leda
e_bt double mag Error on bt
From Leda
it double mag Total I-magnitude
From Leda
e_it double mag Error on it
From Leda
ubt double mag Total U-B color
From Leda
bvt double mag Total B-V color
From Leda
ube double mag Effective U-B color
From Leda
bve double mag Effective B-V 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 21-cm 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 21-cm 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 B-magnitude
From Leda
ubtc double mag Total apparent corrected U-B color
From Leda
bvtc double mag Total apparent corrected B-V 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 21-cm line flux in magnitude (see text)
From Leda
hic double mag 21-cm index bt-m21c 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 B-magnitude
From Leda
summary char Summary and data access