J/ApJ/872/56ivo://CDS.VizieR/J/ApJ/872/56doi:10.26093/cds/vizier.18720056CDSPanopoulou G.V.Tassis K.Skalidis R.Blinov D.Liodakis I.,Pavlidou V.Potter S.B.Ramaprakash A.N.Readhead A.C.S.Wehus I.K.2019-07-16T07:10:53Z2019-06-17T13:07:19ZCDS support team

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

cds-question@unistra.frpolarimetryinterstellar-mediumstellar-distancevisible-astronomyThe availability of large data sets with stellar distance and polarization information will enable a tomographic reconstruction of the (plane-of-the-sky-projected) interstellar magnetic field in the near future. We demonstrate the feasibility of such a decomposition within a small region of the diffuse interstellar medium (ISM). We combine measurements of starlight (R-band) linear polarization obtained using the RoboPol polarimeter with stellar distances from the second Gaia data release. The stellar sample is brighter than 17mag in the R-band and reaches out to several kiloparsecs from the Sun. HI emission spectra reveal the existence of two distinct clouds along the line of sight. We decompose the line-of-sight-integrated stellar polarizations to obtain the mean polarization properties of the two clouds. The two clouds exhibit significant differences in terms of column density and polarization properties. Their mean plane-of-the-sky magnetic field orientation differs by 60{deg}. We show how our tomographic decomposition can be used to constrain our estimates of the polarizing efficiency of the clouds as well as the frequency dependence of the polarization angle of polarized dust emission. We also demonstrate a new method to constrain cloud distances based on this decomposition. Our results represent a preview of the wealth of information that can be obtained from a tomographic map of the ISM magnetic field.2019ApJ...872...56Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/872/56CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/226 : Stellar polarization catalogs agglomeration (Heiles, 2000)I/284 : The USNO-B1.0 Catalog (Monet+ 2003)I/337 : Gaia DR1 (Gaia Collaboration, 2016)I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)I/345 : Gaia DR2 (Gaia Collaboration, 2018)J/ApJS/2/389 : Observations of O and B stars (Hiltner, 1956)J/ApJS/136/463 : Distances and metallicities of HVCs and IVCs (Wakker, 2001)J/A+A/384/1050 : Interstellar polarization. VI. (Berdyugin+, 2002)J/ApJ/603/584 : Polarimetry toward Musca dark cloud (Pereyra+, 2004)J/A+A/462/621 : UBVRI polarisation in NGC 5749 (Vergne+, 2007)J/ApJ/728/104 : Optical polarization for 878 Hipparcos stars (Santos+ 2011)J/A+A/561/A24 : Polarization at high galactic latitude (Berdyugin+, 2014)J/ApJ/807/5 : R-band polarimetry data in Lupus I region (Franco+, 2015)J/MNRAS/452/715 : Optical polarization of the Polaris Flare (Panopoulou+, 2015)J/A+A/594/A116 : HI4PI spectra and column density maps (HI4PI team+, 2016)J/ApJ/838/80 : JHK polarimetry of stars behind bubble N4 (Chen+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/872/56https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/872/56http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/872/56https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/872/56https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/872/56http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/872/56GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/872/56/table2 (Catalog of stellar polarization measurements)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/872/56/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/872/56/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/872/56/table2?GETtext/xml+votable180.050000true294.7865772.089410.0055555555555555566/16084 16086https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/872/56?format=asciiOpticaldefaultJ/ApJ/872/56/table2Catalog of stellar polarization measurementsGaiaGaia DR2 (I/345) catalog identifiermeta.id;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintUSNOUSNO-B1 (I/284) catalog identifiermeta.id.crosscharRAJ2000[293.9/295.9] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[71.8/72.5] Declination (J2000)degpos.eq.dec;meta.mainq[-0.007/0.04] Stokes q value (Q/I)phys.polarization.stokesdoublee_q[0.0009/0.02] The 1{sigma} uncertainty in qstat.errordoubleu[-0.04/0.03] Stokes u value (U/I)phys.polarization.stokesdoublee_u[0.0009/0.02] The 1{sigma} uncertainty in ustat.errordoublePl[0.0002/0.04] Fractional linear polarizationphys.polarization.lineardoublee_Pl[0.0009/0.02] The 1{sigma} uncertainty in Plstat.errordoubledPl[0.0001/0.04] Debiased fractional linear polarizationphys.polarization.lineardoubletheta[-58/72.4] Polarization anglepos.posAng;phys.polarizationfloate_theta[1.4/59.5] The 1{sigma} uncertainty in thetastat.error;pos.posAngfloatrest[21/10806]? Estimated distance (r_est) from Bailer-Jones+ (2018, I/347) (1)pcpos.distanceintnullableb_rest[21/9536]? Lower bound of 68% confidence interval in restpcstat.fit.paramintnullableB_rest[21/12338]? Upper bound of 68% confidence interval in restpcstat.fit.paramintnullableFlag[0/2]? Source flag (2)meta.code.errorintnullableBJ18Display the Gaia DR2 estimated distances from Bailer-Jones+ (2018, I/347)meta.ref.urlchar