English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Magnetic fields are expected to play an important role in accretion processesfor circumstellar disks. Measuring the magnetic field morphology is difficult,especially since polarimetric (sub)millimeter continuum observations may nottrace fields in most disks. The Goldreich-Kylafis (GK) effect suggests thatline polarization is perpendicular or parallel to the magnetic field direction.We attempt to observe CO(2-1), $^{13}$CO(2-1), and C$^{18}$O(2-1) linepolarization toward HD 142527 and IM Lup, which are large, brightprotoplanetary disks. We use spatial averaging and spectral integration tosearch for signals in both disks, and detect a potential CO(2-1) Stokes $Q$signal toward both disks. The total CO(2-1) polarization fractions are 1.57$\pm$ 0.18% and 1.01 $\pm$ 0.10% for HD 142527 and IM Lup, respectively. OurMonte Carlo simulations indicate that these signals are marginal. We also stackStokes parameters based on the Keplerian rotation, but no signal was found.Across the disk traced by dust of HD 142527, the 3$\sigma$ upper limits for$P_{\text{frac}}$ at 0.5$^{\prime\prime}$ ($\sim$80 au) resolution aretypically less than 3% for CO(2-1) and $^{13}$CO(2-1) and 4% forC$^{18}$O(2-1). For IM Lup, the 3$\sigma$ upper limits for these three linesare typically less than 3%, 4%, and 12%, respectively. Upper limits based onour stacking technique are up to a factor of $\sim$10 lower, though stackingareas can potentially average out small-scale polarization structure. We alsocompare our continuum polarization at 1.3 mm to observations at 870 $\mu$m fromprevious studies. The polarization in the northern dust trap of HD 142527 showsa significant change in morphology and an increase in $P_{\text{frac}}$ ascompared to 870 $\mu$m. For IM Lup, the 1.3 mm polarization may be moreazimuthal and has a higher $P_{\text{frac}}$ than at 870 $\mu$m.

Low Level Carbon Monoxide Line Polarization in two Protoplanetary Disks: HD 142527 and IM Lup