J/MNRAS/435/623ivo://CDS.VizieR/J/MNRAS/435/623doi:10.26093/cds/vizier.74350623CDSVika M.Bamford S.P.Haussler B.Rojas A.L.Borch A.Nichol R.C.2024-08-06T20:17:22Z2014-10-09T16:13:27ZCDS support team

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

cds-question@unistra.frgalaxiesphotometrygalaxy-classification-systemsWe demonstrate a new multiwavelength technique for two-dimensional parametric modelling of galaxy surface-brightness profiles, which we have incorporated into the widely used software GALFIT. Our new method, named GALFITM, extends GALFIT3's current single-band fitting process by simultaneously using multiple images of the same galaxy to constrain a wavelength-dependent model. Each standard profile parameter may vary as a function of wavelength, with a user-definable degree of smoothness, from constant to fully free. The performance of GALFITM is evaluated by fitting elliptical Sersic profiles to ugriz imaging data for 4026 galaxies, comprising the original Sloan Digital Sky Survey (SDSS) imaging for 163 low-redshift (v<~7000km/s) galaxies and 3863 artificially redshifted (0.01<~z<~0.25) images of the same galaxies. Comparing results from single-band and multiband techniques, we show that GALFITM significantly improves the extraction of information, particularly from bands with low signal-to-noise ratio (e.g. u and z SDSS bands) when combined with higher signal-to-noise images. We also study systematic trends in the recovered parameters, particularly Sersic index, that appear when one performs measurements of the same galaxies at successively higher redshifts. We argue that it is vital that studies investigating the evolution of galaxy structure are careful to avoid or correct for these biases. The resulting multiband photometric structural parameters for our sample of 163 galaxies are provided. We demonstrate the importance of considering multiband measurements by showing that the Sersic indices of spiral galaxies increase to redder wavelengths, as expected for composite bulge-disc systems. Finally, for the ellipticals in our sample, which should be well represented by single-Sersic models, we compare our measured parameters to those from previous studies.2013MNRAS.435..623Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/435/623CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/435/623https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/435/623http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/435/623https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/435/623https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/435/623http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/435/623GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/435/623/table1 (*Galaxy sample and the fit results as derived from the multiband fitting)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/435/623/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/435/623/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/435/623/table1?GETtext/xml+votable180.050000true175.89447088.942550.0055555555555555566/4149 5202 5244 5492 5596 5610 5631 5818 5950 5961-5962 5966 5975 5978 5982 6034 6090 6093 6119 6448 6609 6619 7177 7207 7214 7231 7241 7386 7485 7498 8195-8196 8225 10025 10739 10841 10856 11006 11097 11246 11253 11306 11319 11387 11394 11401 11453 11460 11789 11800 11832 11905 11944 11947 17493 17509 17747 17754 17761 17776 18002 18011 18800 20008 25599 25946 25960 25966 25997 26068 26090 26175 26214 26217 26223 26234 26268 26303 26313 26315 26338 26344 26346 26361-26362 26365 26377 26388 27030 27243 27285 27347 27406 27458 27650 27653 27669 27712-27714 27718-27720 27725 27730 27738 27740 27743 27763-27765 27767 27773 27800 27857 27861 27907 27912-27914 27936 27938 27944 28035 28039 28123 28172 28517 31345 31352 31365 31376 32462 32487 36734 36785 36789 45050https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/435/623?format=asciiOpticaldefaultJ/MNRAS/435/623/table1*Galaxy sample and the fit results as derived from the multiband fittingrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameGalaxy namemeta.id;meta.maincharHTypeHubble type from NEDmeta.note;src.morph.typecharumagApparent u magnitude (error +/-0.13)magphot.mag;em.opt.UfloatgmagApparent g magnitude (error +/-0.09)magphot.mag;em.opt.BfloatrmagApparent r magnitude (error +/-0.1)magphot.mag;em.opt.RfloatimagApparent i magnitude (error +/-0.11)magphot.mag;em.opt.IfloatzmagApparent z magnitude (error +/-0.12)magphot.mag;em.opt.Ifloatre(u)Effective radius in u band (error +/-12%)arcsecstat.error;phys.angSize;em.opt.Ufloatre(g)Effective radius in g band (error +/-11%)arcsecstat.error;phys.angSizefloatre(r)Effective radius in r band (error +/-12%)arcsecstat.error;phys.angSizefloatre(i)Effective radius in i band (error +/-14%)arcsecstat.error;phys.angSizefloatre(z)Effective radius in z band (error +/-15%)arcsecstat.error;phys.angSizefloatn(u)Sersic index for u band (error +/-10%)stat.fit.paramfloatn(g)Sersic index for g band (error +/-11%)stat.fit.paramfloatn(r)Sersic index for r band (error +/-14%)stat.fit.paramfloatn(i)Sersic index for i band (error +/-15%)stat.fit.paramfloatn(z)Sersic index for z band (error +/-17%)stat.fit.paramfloatSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main