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

(Abridged) The goal of this work is to investigate if SiO, H2O and HCN maseremission within the ALMA frequency range can be detected with observable levelsof fractional linear polarization in the regime where the Zeeman frequency(gOmega) is greater than the stimulated emission rate (R) and the decay rate ofthe molecular state (Gamma). We have used a radiative transfer code tocalculate the fractional linear polarization as a function of the emergingbrightness temperature for a number of rotational transition of SiO, H2O andHCN which have been observed to display maser emission at submillimetrewavelengths. We assume typical magnetic field strengths measured towardsgalactic star forming regions and circumstellar envelopes of late-type starsfrom previous VLBI observations. Since the Land\'e g-factors have not beenreported for the different rotational transitions we have modeled, we performedour calculations assuming conservative values of the Zeeman frequency for thedifferent molecular species. Setting a lower limit for the Zeeman frequencywhich still satisfies the criteria gOmega>R and gOmega>Gamma, we findfractional polarization levels of up to 13%, 14% and 19% for the higher Jtransitions analysed for SiO, H2O and HCN, respectively, without consideringanisotropic pumping or any other non-Zeeman effect. Such upper limits werecalculated assuming a magnetic field oriented perpendicular to the direction ofpropagation of the maser radiation. According to our results SiO, H2O and HCNmaser emission within the ALMA frequency range can be detected with suitablelinear polarization to trace the magnetic field structure towards star formingregions and late-type stars, even if the detected polarization has beenenhanced by non-Zeeman effects.

Linear polarization of submillimetre masers. Tracing magnetic fields with ALMA