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 |