Discovery of Molecular Line Polarization in the Disk of TW Hya
dc.contributor.author | TEAGUE, Richard | |
dc.contributor.author | HULL, Charles | |
hal.structure.identifier | Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB] | |
dc.contributor.author | GUILLOTEAU, S. | |
dc.contributor.author | BERGIN, Edwin | |
dc.contributor.author | DUTREY, Anne | |
dc.contributor.author | HENNING, Thomas | |
dc.contributor.author | KUIPER, Rolf | |
dc.contributor.author | SEMENOV, Dmitry | |
dc.contributor.author | STEPHENS, Ian | |
dc.date.issued | 2021 | |
dc.identifier.issn | 0004-637X | |
dc.description.abstractEn | We report observations of polarized line and continuum emission from the disk of TW Hya using the Atacama Large Millimeter/submillimeter Array. We target three emission lines, 12 CO (3-2), 13 CO (3-2) and CS (7-6), to search for linear polarization due to the Goldreich-Kylafis effect, while simultaneously tracing the continuum polarization morphology at 332 GHz (900 µm), achieving a spatial resolution of 0.5 (30 au). We detect linear polarization in the dust continuum emission; the polarization position angles show an azimuthal morphology, and the median polarization fraction is ∼ 0.2%, comparable to previous, lower frequency observations. Adopting a 'shift-and-stack' technique to boost the sensitivity of the data, combined with a linear combination of the Q and U components to account for their azimuthal dependence, we detect weak linear polarization of 12 CO and 13 CO line emission at a ∼ 10σ and ∼ 5σ significance, respectively. The polarization was detected in the line wings, reaching a peak polarization fraction of ∼ 5% and ∼ 3% for the two molecules between disk radii of 0. 5 and 1. The sign of the polarization was found to flip from the blue-shifted side of the emission to the red-shifted side, suggesting a complex, asymmetric polarization morphology. Polarization is not robustly detected for the CS emission; however, a tentative signal, comparable in morphology to that found for the 12 CO and 13 CO emission, is found at a 3σ significance. We are able to reconstruct a polarization morphology, consistent with the azimuthally averaged profiles, under the assumption that this is also azimuthally symmetric, which can be compared with future higher-sensitivity observations. | |
dc.language.iso | en | |
dc.publisher | American Astronomical Society | |
dc.subject.en | Circumstellar disks (235) | |
dc.subject.en | Radio interferometry (1346) | |
dc.subject.en | Polarimetry (1278) | |
dc.subject.en | Submillimeter astronomy (1647) | |
dc.title.en | Discovery of Molecular Line Polarization in the Disk of TW Hya | |
dc.type | Article de revue | |
dc.identifier.doi | 10.3847/1538-4357/ac2503 | |
dc.subject.hal | Planète et Univers [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA] | |
bordeaux.journal | The Astrophysical Journal | |
bordeaux.volume | 922 | |
bordeaux.peerReviewed | oui | |
hal.identifier | hal-03455233 | |
hal.version | 1 | |
hal.popular | non | |
hal.audience | Internationale | |
hal.origin.link | https://hal.archives-ouvertes.fr//hal-03455233v1 | |
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