J/ApJ/833/176ivo://CDS.VizieR/J/ApJ/833/176doi:10.26093/cds/vizier.18330176CDSClemens D.P.Tassis K.Goldsmith P.F.2017-06-06T07:57:44Z2017-05-16T14:04:55ZCDS support team

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

cds-question@unistra.frmolecular-cloudspolarimetryinfrared-photometryThe magnetic field (B-field) of the starless dark cloud L1544 has been studied using near-infrared (NIR) background starlight polarimetry (BSP) and archival data in order to characterize the properties of the plane-of-sky B-field. NIR linear polarization measurements of over 1700 stars were obtained in the H band and 201 of these were also measured in the K band. The NIR BSP properties are correlated with reddening, as traced using the Rayleigh-Jeans color excess (H-M) method, and with thermal dust emission from the L1544 cloud and envelope seen in Herschel maps. The NIR polarization position angles change at the location of the cloud and exhibit their lowest dispersion there, offering strong evidence that NIR polarization traces the plane-of-sky B-field of L1544. In this paper, the uniformity of the plane-of-sky B-field in the envelope region of L1544 is quantitatively assessed. This allows evaluation of the approach of assuming uniform field geometry when measuring relative mass-to-flux ratios in the cloud envelope and core based on averaging of the radio Zeeman observations in the envelope, as done by Crutcher et al. (2009ApJ...692..844C). In L1544, the NIR BSP shows the envelope B-field to be significantly non-uniform and likely not suitable for averaging Zeeman properties without treating intrinsic variations. Deeper analyses of the NIR BSP and related data sets, including estimates of the B-field strength and testing how it varies with position and gas density, are the subjects of later papers in this series.2016ApJ...833..176Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/833/176CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/340 : UCAC5 Catalogue (Zacharias+ 2017)II/328 : AllWISE Data Release (Cutri+ 2013)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/A+A/555/A109 : ^14^N/^15^N isotopic ratio in L1544 (Bizzocchi+, 2013)J/ApJS/182/143 : SCUPOL Legacy polarimetry of SCUBA (Matthews+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/833/176https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/833/176http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/833/176https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/833/176https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/833/176http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/833/176GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/833/176/table1 (Stellar polarimetry and photometry in the L1544 field)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/833/176/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/833/176/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/833/176/table1?GETtext/xml+votable180.050000true75.8486525.268360.0055555555555555566/243003.830199579824256e-20 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/833/176?format=asciiInfrareddefaultJ/ApJ/833/176/table1Stellar polarimetry and photometry in the L1544 fieldrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqStar sequential number (1)meta.recordintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainmHmag[7.7/19] Mimir H band magnitudemagphot.mag;em.IR.Hfloate_mHmag[0/0.4] Uncertainty in mHmagmagstat.error;phot.magfloatPolp(H)[0/99.9] Debiased linear polarization, H band%phys.polarization.linearfloate_Polp(H)[0.03/99] Uncertainty in Polp(H)%stat.errorfloatPA(H)[0/180] Equatorial polarization position angle (in deg E from N), H banddegpos.posAng;phys.polarizationfloate_PA(H)[0.7/180] Uncertainty in PA(H)degstat.errorfloatQ(H)[-100/92] Stokes Q in H band%phys.polarization.stokes;arith.ratiofloate_Q(H)[0.03/100] Uncertainty in Q(H)%stat.errorfloatU(H)[-80/78] Stokes U in H band%phys.polarization.stokes;arith.ratiofloate_U(H)[0.03/100] Uncertainty in U(H)%stat.errorfloatmKmag[9.9/20] Mimir K band magnitude (2)magphot.mag;em.IR.Kfloate_mKmag[0/0.3]? Uncertainty in mKmagmagstat.error;phot.magfloatnullablePolp(K)[0/88] Debiased linear polarization, K band (2)%phys.polarization.linearfloate_Polp(K)[0.1/100] Uncertainty in Polp(K) (2)%stat.errorfloatPA(K)[0/180] Equatorial polarization position angle (in deg E from N), K band (2)degpos.posAng;phys.polarizationfloate_PA(K)[2/180] Uncertainty in PA(K) (2)degstat.errorfloatQ(K)[-49/100] Stokes Q in K band (2)%phys.polarization.stokes;arith.ratiofloate_Q(K)[0.2/100] Uncertainty in Q(K) (2)%stat.errorfloatU(K)[-62/38] Stokes U in K band (2)%phys.polarization.stokes;arith.ratiofloate_U(K)[0.1/100] Uncertainty in U(K) (2)%stat.errorfloatJmag[8.5/18.9]? 2MASS J magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag[0.01/0.3]? Uncertainty in Jmagmagstat.error;phot.mag;em.IR.JfloatnullableHmag[7.7/16.6]? 2MASS H magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag[0.02/0.3]? Uncertainty in Hmagmagstat.error;phot.mag;em.IR.HfloatnullableKsmag[7.5/16.8]? 2MASS Ks magnitudemagphot.mag;em.IR.Kfloatnullablee_Ksmag[0.01/0.4]? Uncertainty in Ksmagmagstat.error;phot.mag;em.IR.KfloatnullableW1mag[7.3/17.5]? AllWISE W1 band (3.6um) magnitudemagphot.mag;em.IR.3-4umfloatnullablee_W1mag[0.02/0.3]? Uncertainty in W1magmagstat.error;phot.magfloatnullableW2mag[7.4/17.3]? AllWISE W2 band (4.5um) magnitudemagphot.mag;em.IR.4-8umfloatnullablee_W2mag[0.01/1]? Uncertainty in W2magmagstat.error;phot.magfloatnullableWISEDisplay the AllWISE data (Cutri+, 2013, II/328) within 2"meta.ref.urlchar2MDisplay the 2MASS data (Cutri+ 2003, II/246) within 2"meta.ref.urlchar