J/A+A/614/A100ivo://CDS.VizieR/J/A+A/614/A100doi:10.26093/cds/vizier.36140100CDSTahani M.Plume R.Brown J.C.Kainulainen J.2019-02-27T14:09:35Z2018-06-21T08:24:55ZCDS support team

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

cds-question@unistra.frmolecular-cloudsmagnetic-fieldsMagnetic fields pervade in the interstellar medium (ISM) and are believed to be important in the process of star formation, yet probing magnetic fields in star formation regions is challenging. Aims. We propose a new method to use Faraday rotation measurements in small-scale star forming regions to find the direction and magnitude of the component of magnetic field along the line of sight. We test the proposed method in four relatively nearby regions of Orion A, Orion B, Perseus, and California. We use rotation measure data from the literature. We adopt a simple approach based on relative measurements to estimate the rotation measure due to the molecular clouds over the Galactic contribution. We then use a chemical evolution code along with extinction maps of each cloud to find the electron column density of the molecular cloud at the position of each rotation measure data point. Combining the rotation measures produced by the molecular clouds and the electron column density, we calculate the line-of-sight magnetic field strength and direction. In California and Orion A, we find clear evidence that the magnetic fields at one side of these filamentary structures are pointing towards us and are pointing away from us at the other side. Even though the magnetic fields in Perseus might seem to suggest the same behavior, not enough data points are available to draw such conclusions. In Orion B, as well, there are not enough data points available to detect such behavior. This magnetic field reversal is consistent with a helical magnetic field morphology. In the vicinity of available Zeeman measurements in OMC-1, OMC-B, and the dark cloud Barnard 1, we find magnetic field values of -23+/-38uG, -129+/-28uG, and 32+/-101uG, respectively, which are in agreement with the Zeeman measurements.2018A&A...614A.100Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/614/A100CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/702/1230 : Rotation measure image of the sky (Taylor+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/614/A100https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/614/A100http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/614/A100https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/614/A100https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/614/A100http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/614/A100GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/614/A100/table6 (Line-of-sight magnetic field in Perseus)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A100/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A100/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A100/table6?GETtext/xml+votable180.050000true50.0129.690.005555555555555556Cone search capability for table J/A+A/614/A100/table7 (Line-of-sight magnetic field in Perseus (Table 6), but only points with fixed direction)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A100/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A100/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A100/table7?GETtext/xml+votable180.050000true50.0129.690.005555555555555556Cone search capability for table J/A+A/614/A100/table1 (Line-of-sight magnetic field in Orion A)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A100/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A100/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A100/table1?GETtext/xml+votable180.050000true80.56-10.960.005555555555555556Cone search capability for table J/A+A/614/A100/table2 (Line-of-sight magnetic field in Orion A (Table 1), but only points with fixed direction)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A100/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A100/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A100/table2?GETtext/xml+votable180.050000true81.18-10.150.005555555555555556Cone search capability for table J/A+A/614/A100/table3 (Line-of-sight magnetic field in Orion B)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A100/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A100/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A100/table3?GETtext/xml+votable180.050000true85.44-1.920.005555555555555556Cone search capability for table J/A+A/614/A100/table4 (Line-of-sight magnetic field in California)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A100/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A100/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A100/table4?GETtext/xml+votable180.050000true58.338.450.005555555555555556Cone search capability for table J/A+A/614/A100/table5 (Line-of-sight magnetic field in California (Table 4), but only points with fixed direction)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/614/A100/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/614/A100/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/614/A100/table5?GETtext/xml+votable180.050000true58.338.450.0055555555555555565/5348 6/850 853 855-857 859-861 863 869 880-882 1231 1240 1242-1243 1251-1254 1257 1263 1273-1275 1538 1544 1546-1547 1567 1589 1600 1606 1608-1609 1612-1613 1615 1617 1626 1633 1636 1638 1641 21389 21400 21405 21407 21409-21411 21414 21423 21431 21434 21437 21439 21472 21475 21480 21482 21484 21491 21502 22186 22789 22800 22806 22852 22855 22864 23563https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/614/A100?format=asciidefaultJ/A+A/614/A100/table6Line-of-sight magnetic field in PerseusrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPointPoint Numbers in the figures 6, 7, 8, 9meta.idintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainAVExtinction in V bandmagphys.absorption;em.opt.VfloatRMonRotation measure (1)rad.m**-2phys.polarization.rotMeasurefloatRMmcRotation measure of Molecular Cloud (2)rad.m**-2phys.polarization.rotMeasurefloatBlosLine of sight magnetic field of the ClouduGphys.magFieldintE_BlosUpper uncertainty of magnetic FielduGstat.error;stat.maxinte_BlosLower uncertainty of magnetic FielduGstat.errorintJ/A+A/614/A100/table7Line-of-sight magnetic field in Perseus (Table 6), but only points with fixed directionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPointPoint Numbers in the figures 6, 7, 8, 9meta.idintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainAVExtinction in V bandmagphys.absorption;em.opt.VfloatRMonRotation measure (1)rad.m**-2phys.polarization.rotMeasurefloatRMmcRotation measure of Molecular Cloud (2)rad.m**-2phys.polarization.rotMeasurefloatBlosLine of sight magnetic field of the ClouduGphys.magFieldintE_BlosUpper uncertainty of magnetic FielduGstat.error;stat.maxinte_BlosLower uncertainty of magnetic FielduGstat.errorintJ/A+A/614/A100/table1Line-of-sight magnetic field in Orion ArecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPointPoint Numbers in the figures 6, 7, 8, 9meta.idintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainAVExtinction in V bandmagphys.absorption;em.opt.VfloatRMonRotation measure (1)rad.m**-2phys.polarization.rotMeasurefloatRMmcRotation measure of Molecular Cloud (2)rad.m**-2phys.polarization.rotMeasurefloatBlosLine of sight magnetic field of the ClouduGphys.magFieldintE_BlosUpper uncertainty of magnetic FielduGstat.error;stat.maxinte_BlosLower uncertainty of magnetic FielduGstat.errorintJ/A+A/614/A100/table2Line-of-sight magnetic field in Orion A (Table 1), but only points with fixed directionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPointPoint Numbers in the figures 6, 7, 8, 9meta.idintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainAVExtinction in V bandmagphys.absorption;em.opt.VfloatRMonRotation measure (1)rad.m**-2phys.polarization.rotMeasurefloatRMmcRotation measure of Molecular Cloud (2)rad.m**-2phys.polarization.rotMeasurefloatBlosLine of sight magnetic field of the ClouduGphys.magFieldintE_BlosUpper uncertainty of magnetic FielduGstat.error;stat.maxinte_BlosLower uncertainty of magnetic FielduGstat.errorintJ/A+A/614/A100/table3Line-of-sight magnetic field in Orion BrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPointPoint Numbers in the figures 6, 7, 8, 9meta.idintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainAVExtinction in V bandmagphys.absorption;em.opt.VfloatRMonRotation measure (1)rad.m**-2phys.polarization.rotMeasurefloatRMmcRotation measure of Molecular Cloud (2)rad.m**-2phys.polarization.rotMeasurefloatBlosLine of sight magnetic field of the ClouduGphys.magFieldintE_BlosUpper uncertainty of magnetic FielduGstat.error;stat.maxinte_BlosLower uncertainty of magnetic FielduGstat.errorintJ/A+A/614/A100/table4Line-of-sight magnetic field in CaliforniarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPointPoint Numbers in the figures 6, 7, 8, 9meta.idintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainAVExtinction in V bandmagphys.absorption;em.opt.VfloatRMonRotation measure (1)rad.m**-2phys.polarization.rotMeasurefloatRMmcRotation measure of Molecular Cloud (2)rad.m**-2phys.polarization.rotMeasurefloatBlosLine of sight magnetic field of the ClouduGphys.magFieldintE_BlosUpper uncertainty of magnetic FielduGstat.error;stat.maxinte_BlosLower uncertainty of magnetic FielduGstat.errorintJ/A+A/614/A100/table5Line-of-sight magnetic field in California (Table 4), but only points with fixed directionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPointPoint Numbers in the figures 6, 7, 8, 9meta.idintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainAVExtinction in V bandmagphys.absorption;em.opt.VfloatRMonRotation measure (1)rad.m**-2phys.polarization.rotMeasurefloatRMmcRotation measure of Molecular Cloud (2)rad.m**-2phys.polarization.rotMeasurefloatBlosLine of sight magnetic field of the ClouduGphys.magFieldintE_BlosUpper uncertainty of magnetic FielduGstat.error;stat.maxinte_BlosLower uncertainty of magnetic FielduGstat.errorint