J/A+A/614/A116ivo://CDS.VizieR/J/A+A/614/A116doi:10.26093/cds/vizier.36140116CDSRamirez Alegria S.Herrero A.Rubke K.Marin-Franch A.Garcia M.,Borissova J.2019-12-23T08:07:05Z2018-06-22T08:08:09ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyinfrared-sourcesinfrared-astronomyspectroscopyRecent near-infrared data have contributed to unveiling massive and obscured stellar populations in both new and previously known clusters in our Galaxy. These discoveries have lead us to view the Milky Way as an active star-forming machine. We look for young massive cluster candidates as over-densities of OB-type stars. The first search, focused on the Galactic direction l=38, resulted in the detection of two objects with a remarkable population of OB-type star candidates. With a modified version of the friends-of-friends algorithm AUTOPOP and using 2MASS and UKIDSS-GPS near-infrared (J, H, and K) photometry for one of our cluster candidates (Masgomas-6) we selected 30 stars for multi-object and long-slit H and K band spectroscopy. With the spectral classification and the near-infrared photometric data, we derive individual distance, extinction, and radial velocity. Of the 30 spectroscopically observed stars, 20 are classified as massive stars, including OB-types (dwarfs, giants and supergiants), two red supergiants, two Wolf-Rayets (WR122-11 and the new WR122-16), and one transitional object (the LBV candidate IRAS 18576+0341). The individual distances and radial velocities do not agree with a single cluster, indicating that we are observing two populations of massive stars in the same line of sight: Masgomas-6a and Masgomas-6b. The first group of massive stars, located at 3.9kpc, contains both Wolf-Rayets and most of the OB-dwarfs; the second group, located at 9.6kpc, hosts the LBV candidate and an evolved population of supergiants. We are able to identify massive stars at two Galactic arms, but we cannot clearly identify whether these massive stars form clusters or associations.2018A&A...614A.116Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/614/A116CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/614/A116https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/614/A116http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/614/A116https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/614/A116https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/614/A116http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/614/A116GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/614/A116/table3 (Spectroscopically observed stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A116/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A116/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A116/table3?GETtext/xml+votable180.050000true285.04483.79760.005555555555555556Cone search capability for table J/A+A/614/A116/list (List of fits spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A116/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A116/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A116/list?GETtext/xml+votable180.050000true285.044773.797580.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/614/A1166/304177.952274030004205e-20 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/614/A116?format=asciiInfrareddefaultJ/A+A/614/A116/table3Spectroscopically observed starsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintspShow the sepctrummeta.ref.urlcharTypeMassive (MS) or Field (FS) starsmeta.codecharSeqSequential numbermeta.recordintUKIDSSIdentification number from the UKIDSS GPS cataloguemeta.id;meta.mainRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainJmagJ magnitudemagphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.mag;em.IR.JfloatHmagH magnitudemagphot.mag;em.IR.Hfloate_Hmagrms uncertainty on Hmagmagstat.error;phot.mag;em.IR.HfloatKmagKs magnitudemagphot.mag;em.IR.Kfloate_Kmagrms uncertainty on Ksmagmagstat.error;phot.mag;em.IR.KfloatSpTypeSpectral typesrc.spTypecharAK? Estimated extinctionmagphys.absorptionfloatnullableE_AK? Error on AK (upper value)magstat.error;stat.maxfloatnullablee_AK? Error on AK (lower value)magstat.errorfloatnullableDist? Distancekpcpos.distancefloatnullableE_Dist? Error on Dist (upper value)kpcstat.error;stat.maxfloatnullablee_Dist? Error on Dist (lower value)kpcstat.errorfloatnullablen_Dist[a] Note on Dist (1)meta.notecharRV? Radial velocitykm/sphys.veloc;pos.heliocentricintnullablee_RV? rms uncertainty on RVkm/sstat.errorintnullableSNRHSignal-to-noise ratio measured for the H-band spectrumstat.snrintSNRK? Signal-to-noise ratio measured for the K-band spectrumstat.snrintnullableJ/A+A/614/A116/listList of fits spectraNxNumber of pointsmeta.numberintspShow the sepctrummeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainSeqObject identification used in articlemeta.id;instr.setupintblambdaLower value of wavelength interval0.1nmem.wlfloatBlambdaUpper value of wavelength interval0.1nmem.wlfloatdlambdaSpectral resolution0.1nmspect.resolutiondoublesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar