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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Observations of dust polarized emission toward star forming regions trace themagnetic field component in the plane of the sky and provide constraints totheoretical models of cloud collapse. We compare high-angular resolutionobservations of the submillimeter polarized emission of the low-massprotostellar source NGC 1333 IRAS 4A with the predictions of three differentmodels of collapse of magnetized molecular cloud cores. We compute the Stokesparameters for the dust emission for the three models. We then convolve theresults with the instrumental response of the Submillimeter Array observationtoward IRAS 4A. Finally, we compare the synthetic maps with the data, varyingthe model parameters and orientation, and we assess the quality of the fit by a\chi^2 analysis. High-angular resolution observations of polarized dustemission can constraint the physical properties of protostars. In the case ofIRAS 4A, the best agreements with the data is obtained for models of collapseof clouds with mass-to-flux ratio >2 times the critical value, initial uniformmagnetic field of strength ~0.5 mG, and age of the order of a few 10^4 yr sincethe onset of collapse. Magnetic dissipation, if present, is found to occurbelow the resolution level of the observations. Including a previously measuredtemperature profile of IRAS 4A leads to a more realistic morphology andintensity distribution. We also show that ALMA has the capability ofdistinguishing among the three different models adopted in this work. Ourresults are consistent with the standard theoretical scenario for the formationof low-mass stars, where clouds initially threaded by large-scale magneticfields become unstable and collapse, trapping the field in the nascentprotostar and the surrounding circumstellar disk. In the collapsing cloud, thedynamics is dominated by gravitational and magnetic forces.

Comparing star formation models with interferometric observations of the protostar NGC 1333 IRAS 4A. I. Magnetohydrodynamic collapse models