J/A+A/636/A54ivo://CDS.VizieR/J/A+A/636/A54doi:10.26093/cds/vizier.36360054CDSvan Gelder M.L.Kaper L.Japelj J.Ramirez-Tannus M.C.Ellerbroek L.E.,Barba R.H.Bestenlehner J.M.Bik A.Graefener G.de Koter A.,de Mink S.E.Sabbi E.Sana H.Sewilo M.Vink J.S.Walborn N.R.2020-08-21T09:16:46Z2020-04-17T07:47:19ZCDS support team

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

cds-question@unistra.frpre-main-sequence-starsyoung-stellar-objectsob-starsspectroscopyThe process of massive star (M>=8M_{sun}_) formation is still poorly understood. Observations of massive young stellar objects (MYSOs) are challenging due to their rarity, short formation timescale, large distances, and high circumstellar extinction. Here, we present the results of a spectroscopic analysis of a population of MYSOs in the Large Magellanic Cloud (LMC). We took advantage of the spectral resolution and wavelength coverage of X-shooter (300-2500nm), which is mounted on the European Southern Observatory Very Large Telescope, to detect characteristic spectral features in a dozen MYSO candidates near 30 Doradus, the largest starburst region in the Local Group hosting the most massive stars known. The X-shooter spectra are strongly contaminated by nebular emission. We used a scaling method to subtract the nebular contamination from our objects. We detect H{alpha},{beta}, [OI] 630.0nm, CaII infrared triplet, [FeII] 1643.5nm, fluorescent FeII 1687.8nm, H_2_ 2121.8nm, Br{gamma}, and CO bandhead emission in the spectra of multiple candidates. This leads to the spectroscopic confirmation of ten candidates as bona fide MYSOs. We compared our observations with photometric observations from the literature and find all MYSOs to have a strong near-infrared excess. We computed lower limits to the brightness and luminosity of the MYSO candidates, confirming the near-infrared excess and the massive nature of the objects. No clear correlation is seen between the Br_gamma luminosity and metallicity. Combining our sample with other LMC samples results in a combined detection rate of disk features such as fluorescent Fe II and CO bandheads which is consistent with the Galactic rate (40%). Most of our MYSOs show outflow features.2020A&A...636A..54Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/636/A54CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/other/Sci/359.69 : Massive stars in 30 Dor (Schneider+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/636/A54https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/636/A54http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/636/A54https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/636/A54https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/636/A54http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/636/A54GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/636/A54/table1 (*A list of the VLT/X-shooter observations used in the paper)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/636/A54/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/636/A54/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/636/A54/table1?GETtext/xml+votable180.050000true84.63175-69.03738890.0055555555555555566/33094https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/636/A54?format=asciidefaultJ/A+A/636/A54/table1*A list of the VLT/X-shooter observations used in the paperrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObjectObject name (1)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainn_pos[abc] Note on Pos (2)meta.notecharObs.DateObservation datetime.epoch;obsnullableExptimeUUVB exposure timestime.duration;obs.exposurecharExptimeVVIS exposure timestime.duration;obs.exposurecharExptimeNNIR exposure timestime.duration;obs.exposure;em.IR.NIRcharSeeingSeeingarcsecinstr.obsty.seeingfloatRemRemarksmeta.notecharspShow the spectrummeta.ref;pos.framecharFileNameName of the spectrum file in subdirectory spmeta.id;meta.filechar