J/ApJ/850/195ivo://CDS.VizieR/J/ApJ/850/195doi:10.26093/cds/vizier.18500195CDSEswaraiah C.Lai S.-P.Chen W.-P.Pandey A.K.Tamura M.Maheswar G.,Sharma S.Wang J.-W.Nishiyama S.Nakajima Y.Kwon J.Purcell R.,Magalhaes A.M.2018-09-10T08:22:36Z2018-08-20T10:26:15ZCDS support team

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

cds-question@unistra.frh-ii-regionspolarimetryinfrared-photometryThe influence of magnetic fields (B-fields) on the formation and evolution of bipolar bubbles, due to the expanding ionization fronts (I-fronts) driven by the HII regions that are formed and embedded in filamentary molecular clouds, has not been well-studied yet. In addition to the anisotropic expansion of I-fronts into a filament, B-fields are expected to introduce an additional anisotropic pressure, which might favor the expansion and propagation of I-fronts forming a bipolar bubble. We present results based on near-infrared polarimetric observations toward the central ~8'x8' area of the star-forming region RCW 57A, which hosts an HII region, a filament, and a bipolar bubble. Polarization measurements of 178 reddened background stars, out of the 919 detected sources in the JHKs bands, reveal B-fields that thread perpendicularly to the filament long axis. The B-fields exhibit an hourglass morphology that closely follows the structure of the bipolar bubble. The mean B-field strength, estimated using the Chandrasekhar-Fermi method (CF method), is 91+/-8{mu}G. B-field pressure dominates over turbulent and thermal pressures. Thermal pressure might act in the same orientation as the B-fields to accelerate the expansion of those I-fronts. The observed morphological correspondence among the B-fields, filament, and bipolar bubble demonstrate that the B-fields are important to the cloud contraction that formed the filament, to the gravitational collapse and star formation in it, and in feedback processes. The last one includes the formation and evolution of mid- infrared bubbles by means of B-field supported propagation and expansion of I-fronts. These may shed light on preexisting conditions favoring the formation of the massive stellar cluster in RCW 57A.2017ApJ...850..195Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/850/195CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/ApJ/603/584 : Polarimetry toward Musca dark cloud (Pereyra+, 2004)J/MNRAS/363/405 : SIMBA observations of cold cores (Hill+, 2005)J/ApJ/649/759 : Bubbles in the galactic disk (Churchwell+, 2006)J/A+A/450/253 : JHKL photometry of RCW57/NGC3576 (Maercker+, 2006)J/ApJ/670/428 : Bubbles in the galactic disk. II. (Churchwell+, 2007)J/ApJ/667/308 : Weak-line T Tauri in Spitzer c2d Survey. II. (Cieza+, 2007)J/ApJ/657/884 : Spectroscopy of TTau & Herbig Ae/Be candidates (Lee+, 2007)J/A+A/487/993 : MAMBO Mapping of c2d Clouds and Cores (Kauffmann+, 2008)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/ApJ/708/758 : Polarimetry of HH1-2 region (Kwon+, 2010)J/MNRAS/403/1577 : Polarization towards open cluster NGC 6823 (Medhi+, 2010)J/ApJ/741/21 : Polarization of stars in Taurus (Chapman+, 2011)J/MNRAS/415/1202 : BVI photometry in W5E HII region (Chauhan+, 2011)J/ApJ/741/35 : NIR photometry and polarization in NGC 2264 (Kwon+, 2011)J/ApJ/751/138 : VRIJHK photometry of IRAS 09149-4743 region (Santos+, 2012)J/MNRAS/424/2442 : Catalog of bubbles from Milky Way Project (Simpson+, 2012)J/ApJ/783/1 : VRI and H polarization toward Sh 2-29 (Santos+, 2014)J/ApJS/213/1 : The MSFRs Omnibus X-ray Catalog (MOXC) (Townsley+, 2014)J/ApJS/220/17 : Wide-field NIR polarimetry of {rho} Oph cloud (Kwon+, 2015)J/MNRAS/462/2266 : RCW121 stars polarimetric study (Seron Navarrete+, 2016)J/A+A/585/A117 : N131 bubble CO integrated intensity maps (Zhang+, 2016)J/ApJ/836/199 : IRDC G028.23-00.19 NIR polarimetry analysis (Hoq+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/850/195https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/850/195http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/850/195https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/850/195https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/850/195http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/850/195GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/850/195/table1 (The JHKs-band polarimetric and photometric measurements of 1074 stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/850/195/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/850/195/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/850/195/table1?GETtext/xml+votable180.050000true167.82417-61.300040.0055555555555555566/379237.952274030004205e-20 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/850/195?format=asciiInfrareddefaultJ/ApJ/850/195/table1The JHKs-band polarimetric and photometric measurements of 1074 starsHmag[7.4/17]? The H band magnitudemagphot.mag;em.IR.HfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/1074] Internal star identifiermeta.id;meta.mainintf_Seq[*] *: missing IRSF/SIRPOL JHKs photometry; data taken from 2MASSmeta.codecharRAJ2000[167.8/168.2] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-61.4/-61.2] Declination (J2000)degpos.eq.dec;meta.mainPJ[0.2/23.1]? De-biased polarization in J band%phys.polarization;em.IR.Jfloatnullablee_PJ[0.02/4.7]? Uncertainty in PJ%stat.errorfloatnullablePH[0.2/83.2]? De-biased polarization in H band%phys.polarization;em.IR.Hfloatnullablee_PH[0.02/15.5]? Uncertainty in PH%stat.errorfloatnullablePKs[0.1/29.8]? De-biased polarization in K_s_ band%phys.polarizationfloatnullablee_PKs[0.02/7.5]? Uncertainty in PKs%stat.errorfloatnullablethetaJ[0.8/180]? Polarization angle in J banddegpos.posAng;phys.polarization;em.IR.Jfloatnullablee_thetaJ[0.2/28.6]? Uncertainty in thetaJ (1)degstat.errorfloatnullablethetaH[0.1/179.3]? Polarization angle in H banddegpos.posAng;phys.polarization;em.IR.Hfloatnullablee_thetaH[0.1/28.4]? Uncertainty in thetaH (1)degstat.errorfloatnullablethetaKs[0.1/180]? Polarization angle in K_s_ banddegpos.posAng;phys.polarizationfloatnullablee_thetaKs[0.1/28.4]? Uncertainty in thetaKs (1)degstat.errorfloatnullableJmag[7.9/18.2]? The J band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag[0.004/0.4]? Uncertainty in Jmagmagstat.error;phot.mag;em.IR.Jfloatnullablee_Hmag[0.003/0.5]? Uncertainty in Hmagmagstat.error;phot.mag;em.IR.HfloatnullableKsmag[7.2/16.5]? The K_s_ band magnitudemagphot.mag;em.IR.Kfloatnullablee_Ksmag[0.002/0.3]? Uncertainty in Ksmagmagstat.error;phot.mag;em.IR.KfloatnullableClassClassification (2)src.classchar2MDisplay the 2MASS data (II/246) within 0.3"meta.ref.urlintnullable