J/A+A/684/A212ivo://CDS.VizieR/J/A+A/684/A212doi:10.26093/cds/vizier.36840212CDSBeslic I.Coude S.Lis D.C.Gerin M.Goldsmith P.F.Pety J.Roueff A.,Demyk K.Dowell C.D.Einig L.Goicoechea J.R.Levrier F.Orkisz J.,Peretto N.Santa-Maria M.G.Ysard N.Zakardjian A.2024-11-07T20:02:37Z2024-04-29T08:46:09ZCDS support team

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

cds-question@unistra.frmolecular-cloudsmagnetic-fieldsinterstellar-mediumradio-astronomyStar formation is essential in galaxy evolution and the cycling of matter. The support of interstellar clouds against gravitational collapse by magnetic (B-) fields has been proposed to explain the low observed star formation efficiency in galaxies and the Milky Way. Despite the Planck satellite providing a 5-15' all-sky map of the B-field geometry in the diffuse interstellar medium, higher spatial resolution observations are required to understand the transition from diffuse gas to gravitationally unstable filaments. NGC 2024, the Flame Nebula, in the nearby Orion B molecular cloud, contains a young, expanding HII region and a dense filament that harbors embedded protostellar objects. Therefore, NGC 2024 is an excellent opportunity to study the role of B-fields in the formation, evolution, and collapse of filaments, as well as the dynamics and effects of young HII regions on the surrounding molecular gas. We combine new 154 and 216um dust polarization measurements carried out using the HAWC+ instrument aboard SOFIA with molecular line observations of ^12^CN(1-0) and HCO+(1-0) from the IRAM 30-meter telescope to determine the B-field geometry and to estimate the plane of the sky magnetic field strength across the NGC 2024. The HAWC+ observations show an ordered B-field geometry in NGC 2024 that follows the morphology of the expanding HII region and the direction of the main filament. The derived plane of the sky B-field strength is moderate, ranging from 30 to 80uG. The strongest B-field is found at the northern- west edge of the HII region, characterized by the highest gas densities and molecular line widths. In contrast, the weakest field is found toward the filament in NGC 2024. The B-field has a non-negligible influence on the gas stability at the edges of the expanding HII shell (gas impacted by the stellar feedback) and the filament (site of the current star formation).2024A&A...684A.212Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/684/A212CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/684/A212https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/684/A212http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/684/A212https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/684/A212https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/684/A212http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/684/A212GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/684/A212/table2 (Results from non-LTE RADEX modeling)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/684/A212/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/684/A212/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/684/A212/table2?GETtext/xml+votable180.050000true85.4018-1.96420.005555555555555556Cone search capability for table J/A+A/684/A212/list (List of fits files)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/684/A212/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/684/A212/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/684/A212/list?GETtext/xml+votable180.050000true84.9249-1.933680.0055555555555555566/22854-22855https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/684/A212?format=asciiRadiodefaultJ/A+A/684/A212/table1Components of the ^12^CN(1-0), from Milam et al., 2009ApJ...690..837MrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTrans^12^CN(1-0) HF transitionphys.atmol.transProb;phys.atmol.transitioncharNurest[113.48/113.53] Rest frequencyGHzem.freqdoubleVeloff[-77.8/7.51] Relative offsetkm/sobs.paramfloatRI[0.01/0.34] Relative intensityspect.line.intensity;arith.ratiofloatJ/A+A/684/A212/table2Results from non-LTE RADEX modelingrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionRegion in NGC 2024meta.notecharRAJ2000[85.34/85.48] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-1.99/-1.75] Declination (J2000)degpos.eq.dec;meta.mainTkin[27.18/53.04] Kinetic temperatureKphys.temperaturefloatDeltaVCN[0.56/1.24] CN turbulent line widthkm/sspect.line.widthfloatnCN[2.27/13.37] CN number density1000cm**-3meta.id;meta.mainfloatDeltaVHCO+[0.96/1.24] HCO+ turbulent line widthkm/sspect.line.widthfloatnHCO+[2.31/5.39] HCO+ number density1000cm**-3meta.idfloatJ/A+A/684/A212/table3Angle dispersion and magnetic field strengthsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionRegion in NGC 2024meta.notecharThetaMean angle dispersion from sliding window for table3, histogram analysis for tabled1degpos.posAngfloate_ThetaMean angle dispersion errordegstat.error;pos.posAngfloatBdcfCNPOS B using DCF and CN1e-06Gphys.magFieldinte_BdcfCNPOS B using DCF and CN error1e-06Gstat.errorintBdcfHCO+POS B using DCF and HCO+1e-06Gphys.magFieldinte_BdcfHCO+POS B using DCF and HCO+ error1e-06Gstat.errorintBstCNPOS B using ST and CN1e-06Gphys.magFieldinte_BstCNPOS B using ST and CN error1e-06Gstat.errorintBstHCO+POS B using ST and HCO+1e-06Gphys.magFieldinte_BstHCO+POS B using ST and HCO+ error1e-06Gstat.errorintJ/A+A/684/A212/table4Estimated mass-to-flux ratio, Alfvenic Mach number and plasma-betarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionRegion in NGC 2024meta.notecharmuCN[0.09/2.5] Mass-to-flux ratio from BstCNphys.composition.massLightRatiofloatmuHCO+[0.09/1.61] Mass-to-flux ratio from BstHCO+phys.composition.massLightRatiofloatMaCN[1.42/1.91] Alfven Mach number from BstCNphys.veloc;arith.ratiofloatMaHCO+[1.21/2.03] Alfven Mach number from BstHCO+phys.veloc;arith.ratiofloatbetaCN[0.08/1.06] Plasma-beta parameter from BstCNarith.factor;pos.distancefloatbetaHCO+[0.07/0.35] Plasma-beta parameter from BstHCO+arith.factor;pos.distancefloatJ/A+A/684/A212/tabled1Results on the magnetic field strength from histogram analysisBstCNPOS B using ST and CN1e-06Gphys.magFieldintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionRegion in NGC 2024meta.notecharThetaMean angle dispersion from sliding window for table3, histogram analysis for tabled1degpos.posAngfloate_ThetaMean angle dispersion errordegstat.error;pos.posAngfloatBdcfCNPOS B using DCF and CN1e-06Gphys.magFieldinte_BdcfCNPOS B using DCF and CN error1e-06Gstat.errorintBdcfHCO+POS B using DCF and HCO+1e-06Gphys.magFieldinte_BdcfHCO+POS B using DCF and HCO+ error1e-06Gstat.errorinte_BstCNPOS B using ST and CN error1e-06Gstat.errorintBstHCO+POS B using ST and HCO+1e-06Gphys.magFieldinte_BstHCO+POS B using ST and HCO+ error1e-06Gstat.errorintJ/A+A/684/A212/listList of fits filesDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintNz? Number of slices for the datacubesmeta.numberintnullableObs.dateObservation datestime.epoch;obsnullablebVRAD? Lower value of VRAD interval for the datacubeskm/sphys.velocintnullableBVRAD? Upper value of VRAD interval for the datacubeskm/sphys.velocfloatnullabledVRAD? VRAD resolution for the datacubeskm/spos.angResolutionfloatnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fits