J/A+A/593/A7ivo://CDS.VizieR/J/A+A/593/A7doi:10.26093/cds/vizier.35930007CDSHasenberger B.ForbrichJ.Alves J.Wolk S.J.Meingast S.,Getman K.V.Pillitteri I.2017-11-29T11:48:07Z2016-08-29T09:09:33ZCDS support team

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

cds-question@unistra.frextinctioninfrared-sourcesx-ray-sourcesyoung-stellar-objectsWe characterise the relation between the gas and dust content of the interstellar medium towards young stellar objects in the Orion Nebula Cluster. X-ray observations provide estimates of the absorbing equivalent hydrogen column density NH based on spectral fits. Near-infrared extinction values are calculated from intrinsic and observed colour magnitudes (J-H) and (H-Ks) as given by the VISTA Orion A survey. A linear fit of the correlation between column density and extinction values AV yields an estimate of the N_H_/A_V_ ratio. We investigate systematic uncertainties of the results by describing and (if possible) quantifying the influence of circumstellar material as well as the adopted extinction law, X-ray models, and elemental abundances on the NH/AV ratio. Assuming a Galactic extinction law with R_V=3.1 and solar abundances by Anders et al. (1989), we deduce an N_H_/A_V_ ratio of (1.39+/-0.14)*10^21cm^-2^.mag^-1^ for Class III sources in the Orion Nebula Cluster, where the given error does not include systematic uncertainties. This ratio is consistent with similar studies in other star-forming regions and approximately 31% lower than the Galactic value. We find no obvious trends in the spatial distribution of N_H_/A_V_ ratios. Changes in the assumed extinction law and elemental abundances are demonstrated to have a relevant impact on deduced A_V_ and N_H_ values, respectively. Large systematic uncertainties associated with metal abundances in the Orion Nebula Cluster represent the primary limitation for the deduction of a definitive N_H_/A_V_ ratio and the physical interpretation of these results.2016A&A...593A...7Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/593/A7CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)J/AJ/144/192 : Orion A and B Spitzer survey. I. YSO catalog (Megeath+, 2012)J/AJ/146/85 : Spectral types of 1576 stars in ONC (Hillenbrand+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/593/A7https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/593/A7http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/593/A7https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/593/A7https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/593/A7http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/593/A7GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/593/A7/table1 (Catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/593/A7/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/593/A7/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/593/A7/table1?GETtext/xml+votable180.050000true83.6702-5.44430.0055555555555555566/21438-21439 228057.952274030004205e-20 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/593/A7?format=asciiInfraredX-raydefaultJ/A+A/593/A7/table1CatalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCOUPCOUP identification numbermeta.id;meta.mainintRAJ2000Right Ascension (J2000) (1)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (1)degpos.eq.dec;meta.mainNHColumn density (1)1e+22cm**-2phys.columnDensityfloate_NHError of NH1e+22cm**-2stat.errorfloatVISIONVISION identification numbermeta.idcharJmagJ magnitude from VISION (2)magphot.mag;em.IR.Jfloate_JmagError of J magnitude (2)magstat.error;phot.mag;em.IR.JfloatHmagH magnitude from VISION (2)magphot.mag;em.IR.Hfloate_HmagError of H magnitude (2)magstat.error;phot.mag;em.IR.HfloatKsmagK_s magnitude from VISION (2)magphot.mag;em.IR.Kfloate_KsmagError of Ks magnitude (2)magstat.error;phot.mag;em.IR.KfloatSpTypeSpectral typesrc.spTypechar(J-H)0Intrinsic (J-H) magnitudemagphot.color;em.IR;em.IRfloate_(J-H)0Error on (J-H)_0magstat.errorfloat(H-Ks)0Intrinsic (H-K_s) magnitudemagphot.color;em.IR;em.IRfloate_(H-Ks)0Error on (H-K_s)_0magstat.errorfloatAVExtinction for R_V_=3.1 (3)magphys.absorptionfloate_AVError on AVmagstat.errorfloatClassYSO Classification (4)src.classcharSimbadSimbad column added by the CDSmeta.ref.urlchar