VII/299ivo://CDS.VizieR/VII/299CDSShirley R.Duncan K.Campos-Varillas M.C.Hurley P.D.Malek K.,Roehlly Y.Smith M.W.L.Aussel H.Bakx T.Buat V.Burgarella D.,Christopher N.Duivenvoorden S.Eales S.Efstathiou A.,Gonzalez Solares E.A.Griffin M.Jarvis M.Faro B.L.Marchetti L.,McCheyne I.Papadopoulos A.Penner K.Pons E.Prescott M.Rigby E.,Rottgering H.Saxena A.Scudder J.Vaccari M.Wang L. and Oliver S.J.2026-07-30T15:45:59Z2026-07-30T11:01:00ZCDS support team

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

cds-question@unistra.frsurveysgalaxiesphotometryspectroscopyastronomical-object-identificationredshiftedastrometryvisible-astronomyinfrared-astronomyradio-sourcesmillimeter-astronomysubmillimeter-astronomystar-forming-regionsstellar-massesabsolute-magnitudeWe present the Herschel Extragalactic Legacy Project (HELP). This project collates, curates, homogenizes, and creates derived data products for most of the premium multiwavelength extragalactic data sets. The sky boundaries for the first data release cover 1270 deg^2^ defined by the Herschel SPIRE extragalactic survey fields; notably the Herschel Multi-tiered Extragalactic Survey (HerMES) and the Herschel Atlas survey (H-ATLAS). Here, we describe the motivation and principal elements in the design of the project. Guiding principles are transparent or 'open' methodologies with care for reproducibility and identification of provenance. A key element of the design focuses around the homogenization of calibration, meta data, and the provision of information required to define the selection of the data for statistical analysis. We apply probabilistic methods that extract information directly from the images at long wavelengths, exploiting the prior information available at shorter wavelengths and providing full posterior distributions rather than maximum-likelihood estimates and associated uncertainties as in traditional catalogues. With this project definition paper, we provide full access to the first data release of HELP; Data Release 1 (DR1), including a monolithic map of the largest SPIRE extragalactic field at 385 deg^2^ and 18 million measurements of PACS and SPIRE fluxes. We also provide tools to access and analyse the full HELP data base. This new data set includes far-infrared photometry, photometric redshifts, and derived physical properties estimated from modelling the spectral energy distributions over the full HELP sky. All the software and data presented is publicly available.2021MNRAS.507..129Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/VII/299CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/456/1359 : IAC Stripe 82 Legacy Project: Photometry (Fliri+, 2016)J/MNRAS/416/927 : Wide-field optical imaging of 4 fieldsJ/MNRAS/413/971 : Galaxy And Mass Assembly (GAMA) DR1 (Driver+, 2011)J/MNRAS/386/1605 : Luminous K-band selected QSOs from UKIDSS (Maddox+, 2008)J/A+A/622/A103 : Python Code Investigating GALaxy Emission (Boquien+, 2019)J/A+A/590/A102 : VIPERS Multi-Lambda Survey (Moutard+, 2016)J/A+A/570/A11 : The Hawk-I UDS and GOODS Survey (HUGS) (Fontana+, 2014)J/A+A/566/A60 : Optical-NIR catalog of AKARI NEP Deep Field (Oi+, 2014)J/A+A/556/A55 : Multi-color photometry of star-forming galaxiesJ/ApJ/701/428 : The Spitzer Deep, Wide-Field Survey (SDWFS) (Ashby+, 2009)J/ApJ/682/985 : FIREWORKS photometry of GOODS CDF-S (Wuyts+, 2008)J/ApJS/235/36 : SPLASH-SXDF multi-wavelength photometric catalogJ/ApJS/231/7 : The VISTA-CFHT Stripe 82 NIR survey (VICS82) (Geach+, 2017)J/ApJS/225/1 : SpIES: the Spitzer IRAC Equatorial Survey (Timlin+, 2016)J/ApJS/224/24 : The COSMOS2015 catalog (Laigle+, 2016)J/ApJS/223/1 : Multiwavelength catalog in the SEP field (Baronchelli+,2016)J/ApJS/214/24 : 3D-HST+CANDELS catalog (Skelton+, 2014)J/ApJS/210/22 : Herschel Stripe 82 survey (HerS) first catalog (Viero+,2014)J/ApJS/209/22 : SSDF survey: IRAC catalogs (Ashby+, 2013)J/ApJS/208/24 : Spitzer MIR AGN survey. I. (Lacy+, 2013)J/ApJS/193/13 : Spitzer/IRAC sources in the EGS I. SEDs (Barro+, 2011)J/ApJS/187/251 : Ultradeep Ks imaging in the GOODS-N (Wang+, 2010)J/ApJS/176/1 : Subaru/XMM-Newton deep survey (SXDS). II. (Furusawa+, 2008)J/AJ/153/107 : Australian Dark Energy Survey (OzDES) quasar catalogJ/AJ/128/1 : First Look Survey: NOAO R-band Mosaic (Fadda+, 2004)VII/233 : 2MASS All-Sky Extended Source Catalog (XSC)III/334 : VISTA Deep Extragalactic Observations (VIDEO) (Jarvis+,2013)II/377 : Spitzer Data Fusion main catalogue (Vaccari, 2023)II/359 : The VISTA Hemisphere Survey (VHS) catalog DR4.1II/357 : The Dark Energy Survey (DES): Data Release 1 (Abbott+, 2018)II/350 : VLT Survey Telescope ATLAS (Shanks+, 2015)II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+,2016)II/329 : VIKING catalogue data release 1 (Edge+, 2013)II/314 : UKIDSS-DR8 LAS, GCS and DXS Surveys (Lawrence+ 2012)II/301 : The DEEP2-DR1 Photometric Catalog (Coil+ 2004)II/261 : GOODS initial results (Giavalisco+, 2004)II/253 : Chandra Deep Field South: multi-colour data (Wolf+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=VII/299https://vizier.iucaa.in/viz-bin/VizieR-2?-source=VII/299http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=VII/299https://vizier.cds.unistra.fr/viz-bin/votable?-source=VII/299https://vizier.iucaa.in/viz-bin/votable?-source=VII/299http://vizieridia.saao.ac.za/viz-bin/votable?-source=VII/299GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table VII/299/help (Herschel Extragalactic Legacy Project HELP photometric catalogue of extragalactic field sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/VII/299/help?https://vizier.iucaa.in/viz-bin/conesearch/VII/299/help?http://vizieridia.saao.ac.za/viz-bin/conesearch/VII/299/help?GETtext/xml+votable180.050000true134.979824978209450.019060437710990.0055555555555555560/0-11 6/-2.439715709817298e-18 2.903888696868909e-18https://cdsarc.cds.unistra.fr/viz-bin/moc/VII/299?format=asciiOpticalInfraredMillimeterRadiodefaultVII/299/helpHerschel Extragalactic Legacy Project HELP photometric catalogue of extragalactic field sourcesHELPHELP identifier based on J2000 position as HELP_JHHMMSS.sss+DDMMSS.sss (help_id)meta.id;meta.maincharindexedRAJ2000Right Ascension (J2000) (ra)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (dec)degpos.eq.dec;meta.mainhmag? Total AB magnitude of the lowest error h band measurement (m_best_h)magphot.mag;em.IR.HdoublenullableFu? Total flux density in the lowest error u band measurement (f_best_u)uJyphot.flux.density;em.opt.Bdoublenullabler_stellar? Name of Survey from which stellarity is calculated (stellarity_origin)meta.bibcharfOptNIRo[0/7] Flag indicating in which wavelength regimes the source was observed (flag_optnir_obs)meta.codeinte_ymag? Uncertainty on m_best_y (merr_best_y)magstat.error;phot.mag;em.opt.Idoublenullablef_Fi2[0]? Flag set to true for sources for which niether the irac_i2 aperture nor total flux should be used for SED fitting (flag_irac_i2)meta.code.qual;em.IR.4-8umintnullableymag? Total AB magnitude of the lowest error y band measurement (m_best_y)magphot.mag;em.opt.Idoublenullablestellar? Index evaluation is the source is point-source as 0 not point source to 1 point source and generally name stellarity index (stellarity)src.class.starGalaxydoublenullablefClean[0/1] Boolean flag denoting that the source was associated to really near object that were removed during the cleaning procedure (flag_cleaned)meta.codeintM*? Stellar Mass estimated by SED fitting with CIGALE (cigale_mstar)solMassphys.massdoublenullablef_F350sp[0/1]? Flag set to true for sources for which niether the spire_350 aperture nor total flux should be used for SED fitting (flag_spire_350)meta.code.qual;em.mm.750-1500GHzintnullablef_zsp[0/1] Boolean flag set to true when the association of a source to its redshift may be problematic possible mis-cross-association (zspec_association_flag)meta.code;src.redshiftintgmag? Total AB magnitude of the lowest error g band measurement (m_best_g)magphot.mag;em.opt.Bdoublenullablee_i2mag? Uncertainty on m_irac_i2 (merr_irac_i2)magstat.error;phot.mag;em.IR.4-8umdoublenullableFi3? Total flux density in the 5.6um band of The Infrared Array Camera (IRAC) on The Spitzer Space Telescope (f_irac_i3)uJyphot.flux.density;em.IR.4-8umdoublenullableFi2? Total flux density in the 4.5um band of The Infrared Array Camera (IRAC) on The Spitzer Space Telescope (f_irac_i2)uJyphot.flux.density;em.IR.4-8umdoublenullablee_rmag[]? Uncertainty on m_best_r (merr_best_r)magstat.error;phot.mag;em.opt.Rdoublenullablef_Fz[0/1] Flag set to true for sources for spurious measurements in z (flag_best_z)meta.code.qual;em.opt.Iintf_Fi4[0]? Flag set to true for sources for which niether the irac_i4 aperture nor total flux should be used for SED fitting (flag_irac_i4)meta.code.qual;em.IR.8-15umintnullablezphEAZY? Photometric redshift obtained with EAZY (redshift)src.redshift.photdoublenullableFr? Total flux density in the lowest error r band measurement (f_best_r)uJyphot.flux.density;em.opt.Rdoublenullablee_Fu? Uncertainty on f_best_u (ferr_best_u)uJystat.error;phot.flux.density;em.opt.Udoublenullablee_Fk? Uncertainty on f_best_k (ferr_best_k)uJystat.error;phot.flux.density;em.IR.Kdoublenullablee_gmag[]? Uncertainty on m_best_g (merr_best_g)magstat.error;phot.mag;em.opt.Bdoublenullablee_Fpacsr? Uncertainty on f_pacs_red (ferr_pacs_red)uJystat.error;phot.flux.density;em.mm.1500-3000GHzdoublenullableChi2IR? Reduced chi squared of best CIGALE fit to infrared data (cigale_chi2_ironly)stat.fit.chi2doublenullablee_M*? Uncertainty on CIGALE_Mstar (cigale_mstar_err)solMassstat.error;phys.massdoublenullablezmag? Total AB magnitude of the lowest error z band measurement (m_best_z)magphot.mag;em.opt.Idoublenullablef_Fy[0/1]? Flag set to true for sources for spurious measurements in y (flag_best_y)meta.code.qual;em.opt.IintnullableFi4? Total flux density in the 8.0um band of The Infrared Array Camera (IRAC) on The Spitzer Space Telescope (f_irac_i4)uJyphot.flux.density;em.IR.8-15umdoublenullablefMerg[0/1]? Boolean flag denoting a possible mis-association during the cross-matching of the various catalogues (flag_merged)meta.codeintnullablee_Fm24? Uncertainty on f_mips_24 (ferr_mips_24)uJystat.error;phot.flux.density;em.IR.15-30umdoublenullableq_zsp[0/5]? Spectroscopic redshift quality flag FIXME code meaning (zspec_qual)meta.code.qual;src.redshiftintnullableindexede_F500sp? Uncertainty on f_spire_500 (ferr_spire_500)uJystat.error;phot.flux.density;em.mm.400-750GHzdoublenullableFj? Total flux density in the lowest error j band measurement (f_best_j)uJyphot.flux.density;em.IR.Jdoublenullablef_Fi3[0]? Flag set to true for sources for which niether the irac_i3 aperture nor total flux should be used for SED fitting (flag_irac_i3)meta.code.qual;em.IR.4-8umintnullablee_umag? Uncertainty on m_best_u (merr_best_u)magstat.error;phot.mag;em.opt.Udoublenullablee_Fj? Uncertainty on f_best_j (ferr_best_j)uJystat.error;phot.flux.density;em.IR.Jdoublenullablee_i1mag? Uncertainty on m_irac_i1 (merr_irac_i1)magstat.error;phot.mag;em.IR.3-4umdoublenullablee_LdustIR