J/MNRAS/478/5689ivo://CDS.VizieR/J/MNRAS/478/5689doi:10.26093/cds/vizier.74785689CDSLewis C.Spekkens K.2024-08-18T20:20:27Z2022-02-08T13:15:24ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgalaxiescatalogsgalaxy-classification-systemsastronomical-modelsWe present photometric models of 532 disc galaxies in 3.6um images from the Spitzer Survey of Stellar Structure in Galaxies (S^4^G) using the non-parametric DISKFIT algorithm. We first test DISKFIT's performance on 400 synthetic S^4^G-like galaxy images. DISKFIT is unreliable in the bulge region, but accurately disentangles exponential discs from Ferrers bars farther out as long as their position angles differ by more than 5{deg}. We then proceed to model the S^4^G galaxies, successfully fitting 489 of them using an automated approach for initializing DISKFIT, optimizing the model and deriving uncertainties using a bootstrap-resampling technique. The resulting component geometries and surface brightness profiles are compared to those derived by Salo et al. using the parametric model GALFIT. We find generally good agreement between the models, but discrepancies between best-fitting values for individual systems are often significant: the choice of algorithm clearly impacts the inferred disc and bar structure. In particular, we find that DISKFIT typically assigns more light to the bar and less light to the disc relative to the Ferrers and exponential profiles derived using GALFIT in the bar region. Given DISKFIT's reliability at disentangling these components in our synthetic images, we conclude that the surface brightness distributions of barred S^4^G galaxies are not well-represented by these functional forms. The results presented here underscore the importance of validating photometric decomposition algorithms before applying them to real data and the utility of DISKFIT's non-parametric approach at measuring the structure of discs and bars in nearby galaxies.2018MNRAS.478.5689Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/478/5689CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/PASP/122/1397 : Spitzer Survey of Stellar Structure in Galaxies (S4G)J/ApJ/772/135 : 3.6um surface brightness from S4G (Zaritsky+, 2013)J/A+A/562/A121 : ARRAKIS: Atlas of Resonance Rings as Known In S4GJ/A+A/569/A91 : Optical imaging for S4G (Knapen+, 2014)J/MNRAS/441/1992 : Galaxies with disc breaks in S4G and NIRS0S (Laine+, 2014)J/MNRAS/444/3015 : Morphologies of S4G galaxies (Laine+, 2014)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)J/ApJS/219/4 : S4G pipeline 4: multi-component decompositions (Salo+, 2015)J/A+A/587/A160 : 3.6um S4G Galactic bars characterizationJ/A+A/596/A25 : Disc breaks across masses and wavelengths (Laine+, 2016)J/A+A/596/A84 : S4G disk galaxies stellar mass distributionJ/ApJS/234/18 : GALEX/S4G surface brightness profiles. I. (Bouquin+, 2018)J/A+A/631/A94 : Avg pitch angles + spiral amplitudes in S4Ghttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/478/5689https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/478/5689http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/478/5689https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/478/5689https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/478/5689http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/478/5689GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/MNRAS/478/5689/tablea1Galaxies in S^4^G subsampleSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameGalaxy namemeta.id;meta.maincharModelModel used in DiskFit (1)instr.setup;meta.modelledcharl_PAD[~] Limit flag on PAmeta.code.errorcharPAD? Disk position angledegpos.posAngfloatnullablee_PAD? Disk PA errordegstat.errorfloatnullablel_EllD[~] Limit flag on EllDmeta.code.errorcharEllD? Disk Ellipticitysrc.ellipticityfloatnullablee_EllD? Disk Ellipticity errorstat.errorfloatnullablel_PAB[~] Limit flag on PABmeta.code.errorcharPAB? Bar position angledegpos.posAngfloatnullablee_PAB? Bar PA errordegstat.errorfloatnullablel_EllB[~] Limit flag on EllBmeta.code.errorcharEllB? Bar Ellipticitysrc.ellipticityfloatnullablee_EllB? Bar Ellipticity errorstat.errorfloatnullablel_GLD[~] Limit flag on GLDmeta.code.errorcharGLD? Percent of galaxy light in Disk%phys.composition.massLightRatiointnullablee_GLD? Percent of galaxy light in Disk error%stat.errorintnullablel_GLB[~] Limit flag on GLBmeta.code.errorcharGLB? Percent of galaxy light in Bar%phys.composition.massLightRatiofloatnullablee_GLB? Percent of galaxy light in Bar error%stat.errorfloatnullableFlagFlags (2)meta.code.errorcharProf[*] see surface brightness profilesmeta.codecharFileNameName of the file with surface brightness profiles in subdirectory profmeta.idchar