J/MNRAS/526/5187ivo://CDS.VizieR/J/MNRAS/526/5187CDSKirsanova M.S.Moiseev A.V.Boley P.A.2024-02-06T09:01:17Z2024-01-12T15:28:55ZCDS support team

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

cds-question@unistra.frgalaxiesinfrared-sourcesh-ii-regionsinterstellar-mediumchemical-abundancesvisible-astronomyspectroscopyThe S254-258 star-forming complex is a place of massive star formation where five OB-stars have created HII regions, visible as optical nebulae, and disrupted the parental molecular gas. In this work, we study the 3D structure of these HII regions using optical spectroscopy and tunable-filter photometry with the 6- and 1-m telescopes of the Special Astrophysical Observatory of the Russian Academy of Sciences. We construct maps of the optical extinction and find that the HII emission is attenuated by neutral material with 2<=AV<=5mag. The typical electron density in S255, and S257 is ~100cm^-3^, with enhancements up to 200cm^-3^ in their borders, and up to 400cm^-3^ toward the dense molecular cloud between them, where active star formation is taking place. We show that either a model of a clumpy dense neutral shell, where UV photons penetrate through and ionize the gas, or a stellar wind, can explain the shell-like structure of the ionized gas. S255 is surrounded by neutral material from all sides, but S257 is situated on the border of a molecular cloud and does not have dense front and rear walls. The compact HII regions S256 and S258 are deeply embedded in the molecular clouds.2023MNRAS.526.5187Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/526/5187CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/526/5187https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/526/5187http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/526/5187https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/526/5187https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/526/5187http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/526/5187GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/526/5187/listimg (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/526/5187/listimg?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/526/5187/listimg?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/526/5187/listimg?GETtext/xml+votable180.050000true93.2136917.981470.005555555555555556Cone search capability for table J/MNRAS/526/5187/listsp (List of spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/526/5187/listsp?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/526/5187/listsp?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/526/5187/listsp?GETtext/xml+votable180.050000true93.267083317.97886110.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/MNRAS/526/51876/23969https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/526/5187?format=asciiOpticalInfrareddefaultJ/MNRAS/526/5187/listimgList of fits imagesrecnoRecord 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.mainscaleScale of the imagearcsec/pixinstr.scalefloatNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datetime.epoch;obsnullablesizeSize 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.urlcharJ/MNRAS/526/5187/listspList of spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.maincharRAJ2000Simbad right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Simbad declination (J2000)pos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datetime.epoch;obsnullablebAWAVLower value of wavelength interval0.1nmem.wlintBAWAVUpper value of wavelength interval0.1nmem.wlfloatdAWAVWavelength resolution0.1nmspect.resolutionfloatsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory spmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar