Optical and near-infrared photometry in Orion AJ/A+A/564/A29ivo://CDS.VizieR/J/A+A/564/A29doi:10.26093/cds/vizier.35640029CDSBouy H.Alves J.Bertin E.Sarro L.M.Barrado D.2014-09-17T07:00:07Z2014-04-01T08:59:27ZCDS support teamCDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, Francecds-question@unistra.frmolecular-cloudspre-main-sequence-starsvisible-astronomysloan-photometryinfrared-photometryccd-photometryFollowing the recent discovery a large population of young stars in front of the Orion Nebula we carried out an observational campaign with the DECam wide-field camera covering approximately 10 square degrees centered on NGC 1980 to confirm, probe the extent, and characterize this foreground population of pre-main sequence stars. We used multi-wavelength wide field images and catalogs to identify potential foreground pre-main sequence stars using a novel probabilistic technique based on a careful selection of colors and luminosities. We confirmed the presence of a large foreground population towards the Orion A cloud. This population contains several distinct sub-groups including NGC 1980 and NGC 1981 and stretches over several degrees in front of the Orion A cloud. By comparing the location of their sequence in various color-magnitude diagrams to other clusters, we found a distance and an age of 380pc and 5 to 10Myr, in good agreement with previous estimates. Our final sample includes 2123 candidate members and is complete from below the hydrogen burning limit to about 0.3M_{sun}_ where the data starts to be limited by saturation. Extrapolating the mass function to the high masses, we estimated a total number of ~2600 members in the surveyed region.2014A&A...564A..29Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/564/A29CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/12 : Orion A Emission-Line Surveys (Jewell+ 1989)J/AJ/109/709 : K survey of Ori A molecular cloud (Ali+ 1995)J/A+A/327/1177 : Kinematics and electron temperatures in Orion A (Wilson+ 1997)J/A+A/392/239 : IR survey of outflows in Orion A (Stanke+, 2002)J/ApJ/653/383 : SCUBA observations in Orion A South region (Johnstone+, 2006)J/ApJ/665/1194 : Dense cores in the Orion A cloud survey (Ikeda+, 2007)J/A+A/496/153 : Molecular hydrogen flows along Ori A cloud (Davis+, 2009)J/AJ/144/192 : Spitzer survey of Orion A & B. I. YSO catalog (Megeath+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/564/A29https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/564/A29http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/564/A29https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/564/A29https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/564/A29http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/564/A29GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/564/A29/catalog (Positions and griz Y JHKs magnitudes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/564/A29/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/564/A29/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/564/A29/catalog?GETtext/xml+votable180.050000true79.69468222-6.4182450.0055555555555555565/5358-5359 5700-5702 5712 6/21425-21427 21430-21431 21474 21480 21482-21483 22789-22791 22797 22812-22813 22815 228568.650015785639275e-20 4.653515163505597e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/564/A29?format=asciiOpticalInfrareddefault