J/ApJ/775/84ivo://CDS.VizieR/J/ApJ/775/84doi:10.26093/cds/vizier.17750084CDSAndersson B.-G.Piirola V.De Buizer J.Clemens D.P.Uomoto A.,Charcos-Llorens M.Geballe T.R.Lazarian A.Hoang T.Vornanen T.2018-01-04T08:21:22Z2015-04-15T15:00:57ZCDS support team

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

cds-question@unistra.frpolarimetryinterstellar-mediumdwarf-starsh-ii-regionsIn the interstellar medium (ISM), molecular hydrogen is expected to form almost exclusively on the surfaces of dust grains. Due to that molecule's large formation energy (-4.5eV), several dynamical effects are likely associated with the process, including the alignment of asymmetric dust grains with the ambient magnetic field. Such aligned dust grains are, in turn, believed to cause the broadband optical/infrared polarization observed in the ISM. Here, we present the first observational evidence for grain alignment driven by H_2_ formation, by showing that the polarization of the light from stars behind the reflection nebula IC 63 appears to correlate with the intensity of H_2_ fluorescence. While our results strongly suggest a role for "Purcell rockets" in grain alignment, additional observations are needed to conclusively confirm their role. By showing a direct connection between H_2_ formation and a probe of the dust characteristics, these results also provide one of the first direct confirmations of the grain-surface formation of H_2_. We compare our observations to ab initio modeling based on Radiative Torque Alignment (RAT) theory.2013ApJ...775...84Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/775/84CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)I/259 : The Tycho-2 Catalogue (Hog+ 2000)I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)III/92 : A Library of Stellar Spectra (Jacoby+ 1984)VII/20 : Catalogue of HII Regions (Sharpless 1959)J/A+A/541/A52 : Polarization efficiency and dust phase (Voshchinnikov+, 2012)J/A+A/537/A59 : Radial velocities of gamma Cas (Nemravov+, 2012)J/MNRAS/418/2121 : CO 3-2 observations of outflows in W5 (Ginsburg+, 2011)J/ApJ/720/1045 : Polarimetry toward sightlines through ChaI (Andersson+, 2010)J/ApJ/665/369 : Photopolarimetry of Southern Coalsack stars (Andersson+, 2007)J/A+A/470/161 : UBV photometry of HII regions exciting stars (Russeil+, 2007)J/A+A/448/411 : The DRAO polarization survey (Wolleben+, 2006)J/AJ/130/873 : Properties of BQS objects in the SDSS DR3 area (Jester+, 2005)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/775/84https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/775/84http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/775/84https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/775/84https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/775/84http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/775/84GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/775/84/table1 (Source list, optical polarimetry)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/775/84/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/775/84/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/775/84/table1?GETtext/xml+votable180.050000true14.67458360.8783060.0055555555555555566/3031https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/775/84?format=asciiOpticaldefaultJ/ApJ/775/84/table2Polarimetry resultsStar[5/76] Star identifiermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintf_Star[1] Synthesized photometry (1)meta.codecharFiltFilter identifier (UBVRI or H)meta.id;instr.filtercharlambda[0.3/1.7] Central wavelength of filter ({lambda}_c_)umem.wl.central;instr.filterfloatWidth[0.02/0.08]? Filter width ({Delta}{lambda})uminstr.bandwidthfloatnullablePol[0.2/9.5]? Polarization (p)%phys.polarizationfloatnullablee_Pol[0.05/4]? Uncertainty in Pol%stat.errorfloatnullablepolPA[61/140]? Position angle ({theta}); E of Ndegpos.posAng;phys.polarizationintnullablee_polPA[1/23]? Uncertainty in PAdegstat.errorintnullableJ/ApJ/775/84/table1Source list, optical polarimetryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStar[5/76] Background star number (<[APD2013] IC63 #NN> in Simbad)meta.id;meta.mainintRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainInst[AT, ] Instrument (A=ALFOSC; T=TURPOL)meta.id;instrcharExp[180/720]? Exposure time (1)stime.duration;obs.exposureintnullableNpNumber of polarization measures (table 2)meta.numberintnullablePPPolarization plotmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar